Frequently Asked Questions
Heart & Rhythm Cardiology FAQ’s
Cardiac electrophysiology (EP) is the science of elucidating, diagnosing, and treating the electrical activities of the heart. EP doctors do three things:
- Ablate (We burn abnormal heart tissues).
- Implant and manage cardiac devices (We install heart devices).
- Take care of patients (We doctor). Burning (ablation):Catheter ablation is a procedure similar to a heart cath in which a small catheter is placed inside the heart (via a leg vein). The catheter has a small metal tip through which radio-frequency energy can be skillfully delivered to selected parts of the heart. The ablation lesions can eliminate group of cells that have abnormal electrical properties. Catheter ablation is the only cardiac procedure that can be correctly called curative.Installing (implantation): The other procedural aspect of EP is implantation of cardiac devices. Pacemakers, Defibrillators (ICDs) and Cardiac Resynchronization Devices (CRT=Bi-Ventricular) are placed under the skin in the upper chest and are connected to wires that are coursed through veins and positioned into the heart for sensing, pacing and shock delivery. Although it took time to learn the surgical installation process, and attention to details to do it well, the far greater challenge in device management is skillfully applying these complex therapies in the management of patients– the judgment part.Doctoring (treating patients):
Electrophysiologists are not just proceduralists and installers. We are real medical doctors. EP doctors are fortunate because we get to treat a wide range of patients: from the very young, with congenital diseases, to the aged with the diseases of excessive birthdays, and everywhere in between.
Understanding whether to use a catheter, a device, a medication, or in some cases, none-of-the-above, requires us to listen to, exam, and talk with our patients. In other word “being a doctor”.
A heart rate of less than 60 beats per minute in adults is called bradycardia. Your heart rate also depends on your age and physical condition.
- Physically active adults often have a resting heart rate slower than 60 beats per minute but it doesn’t cause problems and it is considered ok.
- Your heart rate may fall below 60 beats per minute during deep sleep.
- Elderly people are more prone to problems with a slow heart rate. Causes of bradycardia
- Problems with the sino-atrial (SA) node, sometimes called the heart’s natural pacemaker
- Problems in the conduction pathways of the heart (electrical impulses are not conducted from the atria to the ventricles)
- Metabolic problems such as hypothermia
- Damage to the heart from heart attack or heart diseasesSymptoms of bradycardiaHeart rate that is too slow can cause insufficient blood flow to the brain with symptoms such as:
- Fainting or near-fainting spells
- In extreme cases, cardiac arrest may occur. Complications of bradycardiaSevere, prolonged untreated bradycardia can cause:
- Heart failure
- Loss of consciousness or fainting (syncope)
- Chest painTreatments for bradycardia
- If you do not experience any symptom, it is not usually treated
- Treatment is needed with prolonged or repeated symptoms
- Can usually be corrected with a pacemaker to speed up the heartrhythm as needed
- If you take medications that may slow heart rate, the doses may beadjusted or the medications may need to be discontinued.
Heart block is an abnormal heart rhythm where the heart beats too slowly due to problems in the conducting system. In this condition, the electrical signals that tell the heart to contract are partially or totally blocked between the upper chambers (atria) and the lower chambers (ventricles). For this reason, it is also called atrioventricular block (AV block).A normal heart beat is initiated by an electrical signal that comes from the heart’s natural pacemaker, the sinoatrial (SA) node, located at the top of the right atrium. The electrical signal then travels through the atria and reaches the atrioventricular (AV) node. After crossing the AV node, the electrical signal passes through the bundle of His. This bundle then divides into thin, wire-like structures called bundle branches that extend into the right and left ventricles. The electrical signal that travels down the bundle branches eventually reached the muscle cells of the ventricles, causing them to contract and pump blood to the body. Heart block occurs when this passage of electricity from top to bottom of the heart is delayed or interrupted.
Some people with heart block will not experience any symptoms, others will have symptoms that may include the following:
- Fainting (syncope)
- Dizziness and lightheadedness
- Chest pain
- Shortness of breath
- Dyspnea on exertion
There are different types of heart block:
- – The electrical impulses are slowed as they pass through the conduction system, but they all successfully reach the ventricles.
First degree heart block – rarely causes symptoms or problems. Well-trained athletes may have first-degree heart block. Medications can also cause this condition. No treatment is generally needed for first-degree heart block.
Second-degree heart block (Type I) – The electrical impulses are delayed further and further with each heartbeat until a beat fails to reach to the ventricles entirely. It sometimes causes dizziness and/or other symptoms. People with normal conduction systems may sometimes have type 1 second degree heart block when they sleep.
Second-degree heart block (Type II) – With this condition, some of the electrical impulses are unable to reach the ventricles. This condition is less common than Type I, and is more serious. Usually, your doctor will recommend a pacemaker to treat type II second degree heart block, as it frequently progresses to third degree heart block.
Third-degree heart block – With this condition, also called complete heart block, none of the electrical impulses from the atria reach the ventricles. When the ventricles (lower chambers) do not receive electrical impulses from the atria (upper chambers), they may generate some impulses on their own, called junctional or ventricular escape beats. Ventricular escape beats, the heart’s naturally occurring backups, are usually very slow. Patients frequently feel poorly in complete heart block, with lightheadedness and fatigue. They sometimes can pass out or faint.
Doctors recommend pacemakers for many reasons. The most common reasons are bradycardia and heart block.
Bradycardia is a heartbeat that is slower than normal. Heart block is a disorder that occurs if an electrical signal is slowed or disrupted as it moves through the heart.
Heart block can happen as a result of aging, damage to the heart from a heart attack, or other conditions that disrupt the heart’s electrical activity. Some nerve and muscle disorders also can cause heart block, including muscular dystrophy.
Your doctor also may recommend a pacemaker if:
- Aging or heart disease damages your sinus node’s ability to set the correct pace for your heart beats. Such damage can cause slower than normal heart beats or long pauses between heart beats. The damage also can cause your heart to switch between slow and fast rhythms. This condition is called sick sinus syndrome.
- You’ve had a medical procedure to treat an arrhythmia called atrial fibrillation. A pacemaker can help regulate your heartbeat after the procedure.
- You need to take certain heart medicines, such as beta blockers. These medicines can slow your heart beats too much.
- You faint or have other symptoms of a slow heartbeat.
- You have heart muscle problems that cause electrical signals to travel too slowly through your heart muscle.
- You have long QT syndrome, which puts you at risk for dangerous arrhythmias. Doctors also may recommend pacemakers for people who have certain types of congenital heart disease or for people who have had heart transplants.
Before recommending a pacemaker, your doctor will consider any arrhythmia symptoms you may have, such as dizziness, unexplained fainting, or shortness of breath. He or she also will consider whether you have a history of heart disease, what medicines you’re currently taking, and the results of heart tests.
Tachycardia refers to an abnormally fast resting heart rate – usually at least 100 beats per minute or more. The threshold of a normal heart rate (pulse) is generally based on the person’s age. Tachycardia can be dangerous; depending on how hard the heart has to work.
In general, the adult resting heart beats are between 60 and 100 times per minute. When an individual has tachycardia the upper or lower chambers of the heart beat significantly faster – sometimes this happens to both chambers.
When the heart beats too rapidly, it pumps less efficiently and blood flow to the rest of the body, including the heart itself is reduced. The higher-than- normal heartbeat means there is an increase in demand for oxygen by the myocardium (heart muscle) – if this persists it can lead to heart attack for weak heart caused by the dying off of oxygen-starved myocardial cells.
Some patients with tachycardia may have no symptoms or complications. Tachycardia significantly increases the risk stroke, sudden cardiac arrest or death.
What are the signs and symptoms of tachycardia?
When the heart beats too rapidly blood may not be pumped to the rest of the body effectively; this may affect organs and tissues which are deprived of oxygen. The following signs and symptoms of tachycardia are possible:
- Palpitation (racing heart beats in your chest)
- Chest pain
- Hypotension (low blood pressure)
- Panting (shortness of breath)
- Sudden weakness
- Syncope (fainting)
- Supraventricular tachycardia (SVT) arises from improper electrical activity of the heart which presents as a rapid heart rhythm originating at or above the atrioventricular node. It can be contrasted with the potentially more dangerous ventricular tachycardias—rapid rhythms that originate within the ventricular tissue.In general, SVT is caused by one of two mechanisms: re-entry and automaticity. Re-entry (such as AV nodal reentrant tachycardia and atrioventricular reciprocating tachycardia) often presents with an almost immediate increase in heart rate. Someone experiencing this type of PSVT may feel the heart rate accelerate from 60 to 200 beats per minute or more. Typically, when it reverts to normal, this is also sudden.The main pumping chamber, the ventricle, is protected (to a certain extent) against excessively high rates arising from the supraventricular areas by a ‘gating mechanism’ at the atrioventricular node, which allows only a proportion of the fast impulses to pass through to the ventricles. In Wolff- Parkinson-White Syndrome, a ‘bypass tract’ avoids this node and its protection and the fast rate may be directly transmitted to the ventricles. This situation has characteristic findings on ECG.In ‘automaticity’ types of SVT (atrial tachycardia, junctional ectopic tachycardia), there is more typically a gradual increase and decrease in the heart rate. These are due to an area in the heart that generates its own electrical signal.Symptoms can arise suddenly and may resolve without treatment. Stress, exercise, and emotion can all result in a normal or physiological increase in heart rate, but can also, more rarely, precipitate SVT. Episodes can last from a few minutes to one or two days, sometimes persisting until treated. The rapid heart rate reduces the opportunity for the “pump” to fill between beats decreasing cardiac output and as a consequence blood pressure. The following symptoms are typical with a rate of 150–270 or more beats per minute:
- Pounding heart
- Shortness of breath
- Chest pain
- Rapid breathing
- Loss of consciousness (in only the most serious cases) Most SVTs are unpleasant rather than life-threatening, although very fast heart rates can be problematic for those with underlying ischemic heart disease or the elderly. Episodes require treatment when they occur, but interval therapy may also be used to prevent or reduce recurrence. While some treatment modalities can be applied to all SVTs, there are specific therapies available to treat some sub-types. Effective treatment consequently requires knowledge of how and where the arrhythmia is initiated and its mode of spread.SVTs can be classified by whether the AV node is involved in maintaining the rhythm. If so, slowing conduction through the AV node will terminate it. If not, AV nodal blocking maneuvers will not work, although transient AV block is still useful as it may unmask an underlying abnormal rhythm.Physical maneuversA number of physical maneuvers increase the resistance of the AV node to transmit impulses (AV nodal block), principally through activation of the parasympathetic nervous system, conducted to the heart by the vagus nerve. These manipulations are collectively referred to as vagal maneuvers.The Valsalva maneuver should be the first vagal maneuver tried and works by increasing intra-thoracic pressure and affecting baroreceptors (pressure sensors) within the arch of the aorta. It is carried out by asking the patient to hold his/her breath while trying to exhale forcibly as if straining during a bowel movement. Holding the nose and exhaling against the obstruction has a similar effect.
Lying on one’s back with the legs vertical (normally against a wall) and relaxing with slow steady breaths may end the episode.
There are other vagal maneuvers including: holding one’s breath for a few seconds, coughing, plunging the face into cold water, (via the diving reflex), drinking a glass of ice cold water, and standing on one’s head. Carotid sinus massage, carried out by firmly pressing the bulb at the top of one of the carotid arteries in the neck, is effective but is often not recommended in the elderly due to the potential risk of stroke in those with atherosclerotic plaque in the carotid arteries.
Reducing coffee, alcohol, or tobacco use or increasing the amount of rest may help to alleviate symptoms. Pressing down gently on the top of closed eyes may also bring heartbeat back to normal rhythm for some people suffering from atrial or supra-ventricular tachycardia (SVT).
Termination of PSVT following adenosine
Adenosine, an ultra-short-acting AV nodal blocking agent, is indicated if vagal maneuvers are not effective. If successful, follow-up therapy with diltiazem, verapamil or metoprolol may be indicated. Adenosine may be safely used during pregnancy.
SVT that does not involve the AV node may respond to other anti- arrhythmic drugs such as sotalol or amiodarone.
If the patient is unstable or other treatments have not been effective, synchronized electrical cardioversion may be used.
Atrial flutter is a type of abnormal fast beating (arrhythmia) in the upper chambers (atria) of the heart. These fast beats prevent the atria from
pushing all the blood into the ventricles. As a result, the ventricles push less blood into the body.
Atrial flutter may be an acute or chronic recurring disorder. When treated, atrial flutter is not usually life-threatening. However, it may increase your risk of developing blood clots and stroke.
This condition can be treated. Contact your doctor if you think you may have atrial flutter.
Atrial flutter may be caused by the following:
- Heart disease
- During the first few weeks after an open-heart surgery
- Infection which may put stresses on the heart
- Intake of substances such as caffeine, alcohol, diet pills, or certaintypes of prescription or over-the-counter medication that affect theelectrical impulses of the heart
- Stress and anxietyRisk FactorsThe following factors increase your chance of developing atrial flutter. If you have any of these risk factors, tell your doctor:
- Heart disease
- Heart surgery
- History of high blood pressure (hypertension)
- Abnormalities of the heart or heart valves
- Overactive thyroid gland (hyperthyroidism)
- History of chronic lung disease (eg, emphysema, chronic obstructivepulmonary disease)
- High levels of stress or anxiety
- Chronic use of caffeine, alcohol, diet pills, or certain types ofprescription or over-the-counter medication (such as cold medicines)
Atrial flutter is more likely to develop in older adults. Symptoms
If you experience any of these symptoms, do not assume the cause is due to atrial flutter. These symptoms may be caused by other, less serious health conditions. If you experience any one of them consistently, see your physician.
Atrial flutter does not always produce symptoms. However, symptoms, when present, include:
- A “fluttering” or tremor-like feeling in the chest
- Palpitations (rapid heart beat or pounding sensation in the chest)
- Pressure or discomfort in the chest
- Shortness of breath
- Dizziness or faintingDiagnosisYour doctor will ask about your symptoms and medical history, and perform a physical exam. Depending on your condition, your doctor may also recommend that you see a cardiologist or arrhythmia specialist. This type of physician may be found in a larger hospital.Tests may include the following:
- Electrocardiogram (ECG, EKG): a test that records the heart’s activity by measuring electrical currents through the heart muscle
- Holter monitor: a device worn around the neck that will continuously record your heart rhythm for a 24-72 hours
- Echocardiogram: a test that uses high-frequency sounds waves (ultrasound) to examine the size, shape, and motion of the heart
- Electrophysiological or EP study: a test in which catheters are threaded through arteries in your groin or neck all the way into your heart. This test may identify the exact source of an abnormal rhythm. An area of the heart responsible for an abnormal rhythm may also be treated during the course of this study. (See ablation therapy)TreatmentThe goal of treating atrial flutter is to slow down the electrical impulses that are sent from the atria (upper chamber of the heart) to the ventricles (lower chamber of the heart), restore normal rhythm, and prevent future episodes.
Talk with your doctor about the best treatment plan for you. Treatment options include the following:
Pharmacologic (Medication) Therapy
Medication may be given to slow the rapid heart rate and convert the atrial flutter to a normal rhythm. These medications may include:
- Beta-blockers (eg, metoprolol)
- Nonhydropyridine calcium channel antagonists (eg, diltiazem,verapamil)Other medications called anitarrhythmics may be used to help your heart maintain a normal rhythm:
- Sotalol (Betapace)
- Propafenone (Rythmol)
- Flecainide (Tambecor)
- Amiodarone (Cordarone)
- Dofetilide (Tikosyn)
- Ibutilide (Corvert)Cardioversion (Defibrillation)An external defibrillator is applied to the chest, and uses electrical current to “shock” the heart back to its normal rhythm.Ablation TherapyFor patients with recurrent atrial flutter that cannot be controlled with medications, ablation can be performed during the course of an EP study. Using the same catheters, an area of the heart from which an abnormal electrical rhythm is generated can be destroyed. This can be curative for atrial flutter.Blood Thinners
When atrial flutter is recurrent, blood thinners such as Coumadin (or Pradaxa, Xarelto, Eliquis) are an important therapy to prevent blood clots that can cause strokes or other serious complications.
To help reduce your chances of getting atrial flutter, take the following steps:
- Reduce or eliminate use of caffeine, stimulants, alcohol, nicotine, certain medications (eg, cold medicine, diet pills) or recreational drugs
- Obtain treatment for any underlying heart or lung disease
- Reduce your levels of stress and anxiety
- Check with your doctor before taking any new medications, herbs, orsupplements
- For this test, 3 or 4 thin flexible wires are passed through a vein in your groin (upper thigh) to your heart. The wires record the heart’s electrical signals and measure electrical conducting properties.Your doctor also uses the wires to electrically stimulate your heart. This allows him or her to see how your heart’s electrical system responds. This test helps pinpoint where the heart’s electrical system is slow, blocked, or damaged. This test can also be used to determine if you are at risk for dangerous rhythms and need a defibrillator.
- Atrial fibrillation (also called AFib or AF) is a quivering or irregular heartbeat (arrhythmia) that can lead to blood clots, stroke, heart failure and other heart-related complications. Some people refer to AF as a quivering heart. Here’s how patients have described their experience:
“My heart flip-flops, skips beats, and feels like it’s banging against my chest wall, especially if I’m carrying stuff up my stairs or bending down.”
“I was nauseated, light-headed, and weak. I had a really fast heartbeat and felt like I was gasping for air.”
“I had no symptoms at all. I discovered my AF at a regular check-up. I’m glad we found it early.”
- What happens during AFib?
Normally, your heart contracts and relaxes to a regular beat. In atrial fibrillation, the upper chambers of the heart (the atria) beat irregularly (quiver) instead of beating effectively to move blood into the ventricles. About 15–20 percent of people who have strokes have this heart arrhythmia.
- It’s the most common “serious” heart rhythm abnormality in peopleover the age of 65 years. Even though untreated atrial fibrillation doubles the risk of heart-related deaths and causes a 4–5-fold increased risk for stroke, many patients are unaware that AF is a serious condition.Atrial flutter occurs when an abnormal conduction circuit develops inside the right atrium, allowing the atria to beat excessively fast, about 250-300 beats per minute.
- These rapid contractions are slowed when they reach the AV node, but are still too fast (typically about 150 beats per minute, or every other atrial beat getting through the AV node to the ventricles).
- This type of rhythm is called tachycardia. Because atrial flutter comes from the atria, it is called a supraventricular (above the ventricles) tachycardia.
Patients with atrial fibrillation are at higher risk to develop a stroke secondary to blood clots formed from sluggish movement of blood within the atria. This clot risk is why patients with this condition are put on blood thinners. People with atrial fibrillation have an increased stroke risk of about five percent per year.
The main danger of atrial flutter is that the heart does not pump blood very well when it is beating too fast.
- Vital organs such as the heart muscle and brain may not get enough blood.
- This can cause them to fail.
- Congestive heart failure, heart attack, and stroke all can result.
Atrial flutter can come and go; it is then known as paroxysmal atrial flutter. An episode of atrial flutter usually lasts hours or days. Less often, atrial flutter is more or less permanent and is known as persistent atrial flutter.
With proper treatment, atrial flutter is rarely life threatening. Complications of atrial flutter can be devastating, but they usually can be prevented with treatment.
In general, atrial flutter should be managed the same as atrial fibrillation. Because both rhythms can lead to the formation of thrombus in the atria, individuals with atrial flutter usually require some form of anticoagulation or anti-platelet agent. Both rhythms can be associated with dangerously fast heart rate and thus require medication for rate and or rhythm control. Additionally, there are some specific considerations particular to treatment of atrial flutter.
Atrial flutter is considerably more sensitive to electrical direct-current cardioversion than atrial fibrillation, and usually requires a lower energy shock. 20-50J is commonly enough to revert to sinus rhythm. Conversely, it is relatively resistant to chemical cardioversion, and often deteriorates into atrial fibrillation prior to spontaneous return to sinus rhythm.
Because of the reentrant nature of atrial flutter, it is often possible to ablate the circuit that causes atrial flutter. This is done in the electrophysiology lab by causing a ridge of scar tissue that crosses the path of the circuit that causes atrial flutter. Ablation of the isthmus, as discussed above, is a common treatment for typical atrial flutter.
How is RFA Performed?
RFA is another way to put the heart back into normal rhythm. It stops the electrical signals that come from places other than the SA node. In RFA, thin wires are threaded into the heart through a vein in the arm or leg. One wire is used to find the problem areas in the heart’s electrical system. Then heat is sent through another wire. The heat destroys a small amount of tissue in the problem areas and stops abnormal heart beats. Once all the problem areas are fixed, the wires are taken out.
The RFA procedure can take 3 hours or more. The doctor moves the wires carefully between the heart’s chambers. After the procedure is over, most people do not have much pain. You will need to stay lying down for a few hours, but you may be able to leave the hospital the same day. Some people need to stay at the hospital overnight or longer. Most people have RFA only one time.
Benefits of RFA
For people who have tried heart rhythm medicines and still have A-fib, RFA is better at getting the heart back into its normal rhythm than trying a heart rhythm medicine for a second time.
The research shows that after 1 year:
- 74 out of 100 people who have RFA are free from A-fib.
- 20 out of 100 people who try a heart rhythm medicine for a secondtime are free from A-fib.We don’t know how RFA and heart rhythm medicines compare after a longer time. Most of the research did not last longer than 1 year.RFA works equally well for men and women and for people of different ages. How long a person has had A-fib also does not affect how well RFA works.
What is Still Not Known?
There is not enough research yet to answer some of the questions you might have about RFA.
- We don’t know for sure how RFA and heart rhythm medicines compare for preventing strokes, congestive heart failure, or death in the future.
- We don’t know for sure whether RFA is better than heart rhythm medicines for people who have never tried taking heart rhythm medicines before.
- We don’t know for sure if people can stop taking medicines to prevent blood clots and strokes more often with RFA or with heart rhythm medicines.
- We don’t know for sure which treatment (RFA or heart rhythm medicines) makes people feel better overall.Risks of RFASome possible problems with RFA are bleeding or pain where the wires are inserted. More serious problems are possible, but they are uncommon.StrokeRFA can cause problems that lead to a stroke.
• About 1 out of 100 people who have RFA have a stroke from the procedure.
Bleeding around the heart
RFA can cause bleeding problems around the heart. Sometimes RFA causes a leak in the wall of the heart. If enough blood leaks into the pocket around the heart, it can put pressure on the heart. This is called cardiac tamponade (tamp-uh-NOD). If it happens, the blood needs to be removed from the pocket around the heart. Most of the time, this is done by inserting a needle through the chest. Sometimes it requires surgery.
• Cardiac tamponade happens in about 1 out of 100 people who have RFA.
Sometimes, the bleeding problem is more serious. In rare cases, a hole can form between the heart and esophagus (eh-SAW-fuh-gus) after RFA. If this happens, the blood leaks from the heart into the esophagus. It has happened with only a few people who have had RFA. When it happens, it can cause severe bleeding and death.
Pulmonary vein narrowing
The pulmonary veins carry blood from the lungs to the heart. RFA destroys problem areas near the pulmonary veins to stop A-fib. The scars that form afterward can cause the veins to narrow.
- Pulmonary vein narrowing happens in less than 1 out of 100 people who have RFA.
- Usually, pulmonary vein narrowing does not cause symptoms and does not need treatment.
Sick sinus syndrome is a type of arrhythmia. It is a group of signs and symptoms that tells doctors that the SA node is not working properly. The SA node usually sends electrical impulses at a certain rate, but if the SA node is not working properly, the heart may beat too fast, too slow, or both.
What causes sick sinus syndrome?
Sick sinus syndrome usually develops slowly over many years, and doctors do not always know the cause. It occurs more often in people over 50, but children may develop the condition after having open heart surgery.
What are the signs and symptoms?
Many people with sick sinus syndrome do not have symptoms, or they do not think their symptoms are serious enough for them to see a doctor.
Here are some signs and symptoms of sick sinus syndrome.
- Fainting (called syncope)
- Dizziness or lightheadedness
- Confusion that comes and goes
- Heart palpitations (the feeling that the heart has skipped a beat)
- Chest pain
- Shortness of breath
- Muscle achesHow is sick sinus syndrome diagnosed?Sick sinus syndrome can be hard to diagnose because you may not have many symptoms. Your doctor will take a medical history, ask about your symptoms, and listen to your heart with a stethoscope. With the stethoscope, the doctor may be able to hear an irregular heartbeat, which can be a sign of sick sinus syndrome. Other diagnostic tests that your doctor may order include
- Electrocardiogram (ECG or EKG), which is the best test for diagnosing arrhythmia. This test helps doctors analyze the electrical currents of your heart and determine the type of arrhythmia you have.
- Holter monitoring, which gets a non-stop reading of your heart rate and rhythm over a 24-hour period (or longer). Doctors can then look at the recording to find out what causes your arrhythmia.
- Event monitors, which are devices that record problems that may not be found within a 24-hour period.
- Electrophysiology studies (EPS), which are usually done in a cardiac catheterization laboratory. Electrical impulses from your heart are mapped out and help doctors find out what kind of arrhythmia you have and whether it is caused by sick sinus syndrome..How is sick sinus syndrome treated?If you do not have any symptoms, you will not need treatment for sick sinus syndrome. If you do have symptoms, your doctor may want you to stop taking certain medicines and avoid food and drinks that make your symptoms worse.
If sick sinus syndrome is causing a slow heart rate (bradycardia), you may need to have a pacemaker implanted and you may need to take antiarrhythmic medicines.
If sick sinus syndrome is causing a fast heart rate (tachycardia), it may be treated with antiarrhythmic medicines. Sometimes a procedure called radiofrequency ablation is also recommended to treat tachycardia.
Ventricular tachycardia (V-tach or VT) is a type of tachycardia, or a rapid heart beat that arises from improper electrical activity of the heart presenting as a rapid heart rhythm, that starts in the bottom chambers of the heart, called the ventricles. The ventricles are the main pumping chambers of the heart. This is a potentially life-threatening arrhythmia because it may lead to ventricular fibrillation, asystole, and sudden death.
Therapy may be directed either at terminating an episode of the arrhythmia or at suppressing a future episode from occurring. The treatment for stable VT is tailored to the specific patient, with regard to how well the individual tolerates episodes of ventricular tachycardia, how frequently episodes occur, their comorbidities, and their wishes. Patients suffering from pulseless VT or unstable VT are hemodynamically compromised and require immediate cardioversion.
Synchronized electrical cardioversion
If the patient still has a pulse, it is usually possible to terminate a VT episode with a direct current shock across the heart, that is delivered from one side of the chest to the other, or from the front to the back. This is ideally synchronized to the patient’s heartbeat, in order to avoid degeneration of the rhythm to ventricular fibrillation. As this is quite uncomfortable, shocks should be delivered only to an unconscious or sedated patient. As a reminder, this is different from defibrillating the patient; see next paragraph.
A patient with pulseless VT or ventricular fibrillation will be unconscious and treated as an emergency on an ACLS protocol, given high-energy (360J with a monophasic defibrillator, or 200J with a biphasic defibrillator) unsynchronised cardioversion (defibrillation).
The shock may be delivered to the outside of the chest using the two pads of an external defibrillator, or internally to the heart by an implantable cardioverter-defibrillator (ICD) if one has previously been inserted.
An ICD may also be set to attempt to overdrive pace the ventricle. Pacing the ventricle at a rate faster than the underlying tachycardia can sometimes be effective in terminating the rhythm. If this fails after a short trial, the ICD will usually stop pacing, charge up and deliver a defibrillation grade shock.
Catheter ablation is a key therapeutic modality for patients with recurrent VT.
There was consensus among the task force members that catheter ablation for VT should be considered early in the treatment of patients with recurrent VT. In the past, ablation was often not considered until pharmacological options had been exhausted, often after the patient had suffered substantial morbidity from recurrent episodes of VT and ICD shocks. Antiarrhythmic medications can reduce the frequency of ICD therapies, but have disappointing efficacy and side effects. Advances in technology and understanding of VT substrates now allow ablation of multiple and unstable VTs with acceptable safety and efficacy, even in patients with advanced heart disease.
Antiarrhythmic drug therapy
Drugs such as amiodarone or procainamide may be used in addition to defibrillation to terminate VT while the underlying cause of the VT can be determined. As hypomagnesia is a common cause of VT, stat dose magnesium sulphate can be given for torsades or if hypomagnesemia is found/suspected.
Long-term anti-arrhythmic therapy may be indicated to prevent recurrence of VT. Beta-blockers and a number of class III anti-arrhythmics are
commonly used. Lidocaine is now being replaced by amiodarone as the first-line anti-arrhythmic treatment of VT.
The implantation of an ICD is more effective than drug therapy for prevention of sudden cardiac death due to VT and VF, but may be constrained by cost issues, as well as patient co-morbidities and patient preference.
Cardiomyopathy refers to diseases of the heart muscle. These diseases have a variety of causes, symptoms, and treatments.
In cardiomyopathy, the heart muscle becomes enlarged, thick, or rigid. In rare cases, the muscle tissue in the heart is replaced with scar tissue.
As cardiomyopathy worsens, the heart becomes weaker. It’s less able to pump blood through the body and maintain a normal electrical rhythm. This can lead to heart failure or arrhythmia. In turn, heart failure can cause fluid to build up in the lungs, ankles, feet, legs, or abdomen.
The weakening of the heart also can cause other severe complications, such as heart valve problems.
The four main types of cardiomyopathy are:
- Dilated cardiomyopathy
- Hypertrophic cardiomyopathy
- Restrictive cardiomyopathy
- Arrhythmogenic right ventricular dysplasia (ARVD)The different types of the disease have different causes, signs and symptoms, and outcomes.Cardiomyopathy can be acquired or inherited. “Acquired” means you aren’t born with the disease but you develop it due to another disease, condition,
or factor. “Inherited” means your parents passed the gene for the disease on to you. In many cases, the cause of cardiomyopathy isn’t known.
Cardiomyopathy can affect people of all ages. However, certain age groups are more likely to have certain types of cardiomyopathy. This document focuses on cardiomyopathy in adults.
Some people who have cardiomyopathy have no signs or symptoms and need no treatment. For other people, the disease develops rapidly, symptoms are severe, and serious complications occur.
Treatments for cardiomyopathy include lifestyle changes, medicines, surgery, implanted devices to correct arrhythmias, and a nonsurgical procedure. These treatments can control symptoms, reduce complications, and stop the disease from getting worse.
Types of Cardiomyopathy
Dilated cardiomyopathy is the most common type of the disease. It mostly occurs in adults aged 20 to 60. Men are more likely than women to have this type of cardiomyopathy.
Dilated cardiomyopathy affects the heart’s ventricles and atria. These are the lower and upper chambers of the heart, respectively.
The disease often starts in the left ventricle, the heart’s main pumping chamber. The heart muscle begins to dilate (stretch and become thinner). This causes the inside of the chamber to enlarge. The problem often spreads to the right ventricle and then to the atria as the disease gets worse.
When the chambers dilate, the heart muscle doesn’t contract normally. Also, the heart can’t pump blood very well. Over time, the heart becomes weaker and heart failure can occur. Symptoms of heart failure include fatigue (tiredness); swelling of the ankles, feet, legs, and abdomen; and shortness of breath.
Dilated cardiomyopathy also can lead to heart valve problems, arrhythmias, and blood clots in the heart.
Hypertrophic cardiomyopathy is very common and can affect people of any age. About 1 out of every 500 people has this type of cardiomyopathy. It affects men and women equally. Hypertrophic cardiomyopathy is the most common cause of sudden cardiac arrest (SCA) in young people, including young athletes.
This type of cardiomyopathy occurs when the walls of the ventricles (usually the left ventricle) thicken. Despite this thickening, the ventricle size often remains normal.
Hypertrophic cardiomyopathy may block blood flow out of the ventricle. When this happens, the condition is called obstructive hypertrophic cardiomyopathy. In some cases, the septum thickens and bulges into the left ventricle. (The septum is the wall that divides the left and right sides of the heart.) In both cases, blood flow out of the left ventricle is blocked.
As a result of the blockage, the ventricle must work much harder to pump blood out to the body. Symptoms can include chest pain, dizziness, shortness of breath, or fainting.
Hypertrophic cardiomyopathy also can affect the heart’s mitral valve, causing blood to leak backward through the valve.
Sometimes the thickened heart muscle doesn’t block blood flow out of the left ventricle. This is called nonobstructive hypertrophic cardiomyopathy. The entire ventricle may become thicker, or the thickening may happen only at the bottom of the heart. The right ventricle also may be affected.
In both types (obstructive and nonobstructive), the thickened muscle makes the inside of the left ventricle smaller, so it holds less blood. The walls of the ventricle also may stiffen. As a result, the ventricle is less able to relax and fill with blood.
These changes cause increased blood pressure in the ventricles and the blood vessels of the lungs. Changes also occur to the cells in the damaged
heart muscle. This may disrupt the heart’s electrical signals and lead to arrhythmias.
Rarely, people who have hypertrophic cardiomyopathy have no signs or symptoms, and the condition doesn’t affect their lives. Others have severe symptoms and complications, such as serious arrhythmias, an inability to exercise, or extreme fatigue with little physical activity.
Rarely, people who have this type of cardiomyopathy can have SCA during very vigorous physical activity. The physical activity can trigger dangerous arrhythmias. If you have this type of cardiomyopathy, talk to your doctor about what types and amounts of physical activity are safe for you.
Restrictive cardiomyopathy tends to mostly affect older adults. In this type of the disease, the ventricles become stiff and rigid. This is due to abnormal tissue, such as scar tissue, replacing the normal heart muscle.
As a result, the ventricles can’t relax normally and fill with blood, and the atria become enlarged. Over time, blood flow in the heart is reduced. This can lead to problems such as heart failure or arrhythmias.
Arrhythmogenic Right Ventricular Dysplasia
Arrhythmogenic right ventricular dysplasia (ARVD) is a rare type of cardiomyopathy. ARVD occurs when the muscle tissue in the right ventricle dies and is replaced with scar tissue.
This process disrupts the heart’s electrical signals and causes arrhythmias. Symptoms include palpitations and fainting after physical activity.
ARVD usually affects teens or young adults. It can cause SCA in young athletes. Fortunately, such deaths are rare.
Other Names for Cardiomyopathy
- Alcoholic cardiomyopathy. This term is used when overuse of alcohol causes the disease.
- Congestive cardiomyopathy.
- Diabetic cardiomyopathy.
- Familial dilated cardiomyopathy.
- Idiopathic cardiomyopathy.
- Ischemic cardiomyopathy. This term is used when coronary arterydisease or heart attack causes the disease.
- Peripartum cardiomyopathy. This term is used when the diseasedevelops in a woman shortly before or after she gives birth.
- Primary cardiomyopathy.Other names for Hypertrophic Cardiomyopathy
- Asymmetric septal hypertrophy
- Familial hypertrophic cardiomyopathy
- Hypertrophic nonobstructive cardiomyopathy
- Hypertrophic obstructive cardiomyopathy
- Idiopathic hypertrophic subaortic stenosisOther names for Restrictive Cardiomyopathy
• Infiltrative cardiomyopathy
Other names for Arrhythmogenic Right Ventricular Dysplasia
- Arrhythmogenic right ventricular cardiomyopathy
- Right ventricular cardiomyopathy
- Right ventricular dysplasiaWhat causes Cardiomyopathy?Cardiomyopathy can be acquired or inherited. “Acquired” means you aren’t born with the disease, but you develop it due to another disease, condition, or factor.”Inherited” means your parents passed the gene for the disease on to you. Researchers continue to look for the genetic links to cardiomyopathy. They also continue to explore how these links cause or contribute to the various types of cardiomyopathy.Many times, the cause of cardiomyopathy isn’t known. This is often the case when the disease occurs in children.Dilated Cardiomyopathy
In more than half of the cases of dilated cardiomyopathy, the cause isn’t known. As many as one-third of the people who have dilated cardiomyopathy inherit it from their parents.
Certain diseases, conditions, and substances also can cause the disease, such as:
- Coronary artery disease, heart attack, diabetes, thyroid disease, viral hepatitis, and HIV
- Infections, especially viral infections that inflame the heart muscle
- Alcohol, especially if you also have a poor diet
- Complications during the last month of pregnancy or within 5 monthsof birth
- Certain toxins, such as cobalt
- Certain drugs (such as cocaine and amphetamines) and twomedicines used to treat cancer (doxorubicin and daunorubicin)Hypertrophic CardiomyopathyMost cases of hypertrophic cardiomyopathy are inherited. It also can develop over time because of high blood pressure or aging.Sometimes, other diseases, such as diabetes or thyroid disease, can cause hypertrophic cardiomyopathy. Sometimes the cause of hypertrophic cardiomyopathy isn’t known.Restrictive CardiomyopathyCertain diseases and conditions can cause restrictive cardiomyopathy, including:
- Hemochromatosis. This is a disease in which too much iron builds up in your body. The extra iron is toxic to the body and can damage the organs, including the heart.
- Sarcoidosis. This is a disease that causes inflammation (swelling). It can affect various organs in the body. The swelling is due to an abnormal immune response. This abnormal response causes tiny lumps of cells to form in the body’s organs, including the heart.
- Amyloidosis. This is a disease in which abnormal proteins build up in the body’s organs, including the heart.
• Connective tissue disorders. Arrhythmogenic Right Ventricular Dysplasia
Researchers think that arrhythmogenic right ventricular dysplasia is an inherited disease.
Who is at risk for Cardiomyopathy?
People of all ages can have cardiomyopathy. However, certain types of the disease are more common in certain groups.
Dilated cardiomyopathy is more common in African Americans than in Whites. This type of the disease also is more common in men than women.
Teens and young adults are more likely than older people to have arrhythmogenic right ventricular dysplasia, although it’s rare in both groups.
Major risk factors
Certain diseases, conditions, or factors can raise your risk for cardiomyopathy. Major risk factors include:
- A family history of cardiomyopathy, heart failure, or sudden cardiac arrest (SCA)
- A disease or condition that can lead to cardiomyopathy, such as coronary artery disease, heart attack, or a viral infection that inflames the heart muscle
- Diabetes, other metabolic diseases, or severe obesity
- Diseases that can damage the heart, such as hemochromatosis,sarcoidosis, or amyloidosis
- Long-term alcoholism
- Long-term high blood pressureSome people who have cardiomyopathy never have signs or symptoms. That’s why it’s important to identify people who may be at high risk for the disease. This can help prevent future problems, such as serious arrhythmias or SCA.What are the signs and symptoms of Cardiomyopathy?
Some people who have cardiomyopathy never have signs or symptoms. Others don’t have signs or symptoms in the early stages of the disease.
As cardiomyopathy worsens and the heart weakens, signs and symptoms of heart failure usually occur. These signs and symptoms include:
- Shortness of breath or trouble breathing.
- Fatigue (tiredness).
- Swelling in the ankles, feet, legs, and abdomen. Rarely, swelling mayoccur in the veins of your neck.Other signs and symptoms can include dizziness, lightheadedness, fainting during physical activity, chest pain, arrhythmias, and heart murmur (an extra or unusual sound heard during a heartbeat).How is Cardiomyopathy diagnosed?Your doctor will diagnose cardiomyopathy based on your medical history, a physical exam, and the results from tests and procedures.Specialists involvedOften, a cardiologist or pediatric cardiologist diagnoses and treats cardiomyopathy. A cardiologist is a doctor who specializes in treating heart diseases. A pediatric cardiologist is a doctor who specializes in treating heart diseases in children.Medical historyYour doctor will want to learn about your medical history. He or she will want to know what symptoms you have and how long you’ve had them. Your doctor also will want to know whether anyone in your family has had cardiomyopathy, heart failure, or sudden cardiac arrest.Physical examYour doctor will use a stethoscope to listen to your heart and lungs for sounds that may suggest cardiomyopathy. These sounds may even suggest a certain type of the disease.
For example, the loudness, timing, and location of a heart murmur may suggest hypertrophic obstructive cardiomyopathy. A “crackling” sound in the lungs may be a sign of heart failure. (This condition often develops in the later stages of cardiomyopathy.)
Physical signs also help your doctor diagnose cardiomyopathy. Swelling of the ankles, feet, legs, or abdomen suggests fluid buildup, a sign of heart failure.
Signs or symptoms of cardiomyopathy may be found during a routine exam. For example, your doctor may hear a heart murmur or you may have abnormal test results.
You may have one or more of the following tests to diagnose cardiomyopathy.
Blood tests: During a blood test, a small amount of blood is taken from your body. It’s usually drawn from a vein in your arm using a thin needle. The procedure usually is quick and easy, although it may cause some short-term discomfort.
Blood tests give your doctor information about your heart and help rule out other conditions.
Chest x ray: A chest x ray takes pictures of the organs and structures inside your chest, including your heart, lungs, and blood vessels. This test can show whether your heart is enlarged. A chest x ray also can show whether fluid is building up in your lungs.
EKG (electrocardiogram): An EKG is a simple test that records the heart’s electrical activity. This test shows how fast your heart is beating and whether the rhythm of your heartbeat is steady or irregular. An EKG also records the strength and timing of electrical signals as they pass through each part of your heart.
This test is used to detect and study many heart problems, such as heart attack, arrhythmia, and heart failure. EKG results also can suggest other disorders that affect heart function.
Echocardiography: Echocardiography is a test that uses sound waves to create a moving picture of your heart. The picture shows how well your heart is working and its size and shape.
There are several different types of echocardiography, including a stress echocardiogram, or “stress echo.” This test is done as part of a stress test. A stress echo can show whether you have decreased blood flow to your heart, a sign of coronary artery disease.
Another type of echo is a transesophageal echo, or TEE. TEE provides a view of the back of the heart.
For a TEE, a sound wave wand is put on the end of a special tube. The tube is gently passed down your throat and into your esophagus (the passage leading from your mouth to your stomach). You will be given medicine to relax you during this procedure.
Stress test: Some heart problems are easier to diagnose when your heart is working hard and beating fast. During stress testing, you exercise (or are given medicine) to make your heart work hard and beat fast while heart tests are done.
These tests may include nuclear heart scanning, echocardiography, magnetic resonance imaging (MRI), and positron emission tomography (PET) scanning of the heart.
You may have one or more medical procedures to confirm a diagnosis or if surgery is planned. These procedures may include cardiac catheterization, coronary angiography, or myocardial biopsy.
Cardiac Catheterization: This procedure checks the pressure and blood flow in your heart’s chambers. The procedure also allows your doctor to collect blood samples and look at your heart’s arteries using x-ray imaging.
During cardiac catheterization, a long, thin, flexible tube called a catheter is put into a blood vessel in your arm, groin (upper thigh), or neck and threaded to your heart. This allows your doctor to study the inside of your arteries to look for blockages.
Coronary Angiography: This procedure often is done with cardiac catheterization. During the procedure, dye that can be seen on an x ray is injected into your coronary arteries. The dye lets your doctor study the flow of blood through your heart and blood vessels.
Dye also may be injected into your heart chambers. This allows your doctor to study the pumping function of your heart.
Myocardial biopsy: For this procedure, your doctor removes a piece of your heart muscle. This can be done during cardiac catheterization. The heart muscle is studied under a microscope to see whether changes in cells have occurred that may suggest cardiomyopathy.
The biopsy is useful for diagnosing some types of cardiomyopathy.
Some types of cardiomyopathy run in families. Thus, your doctor may suggest genetic testing to look for the disease in your parents, brothers and sisters, or other family members.
Genetic testing can show how the disease runs in families. It also can find out the chances of parents passing the genes for the disease on to their children.
Genetic testing also may be useful if your doctor thinks you may have cardiomyopathy, but you don’t yet have signs or symptoms. Your doctor can then start treatment early, when it may be more effective.
How is Cardiomyopathy treated?
Not everyone who has cardiomyopathy needs treatment. People who have no signs or symptoms may not need treatment. In some cases, dilated cardiomyopathy that comes on suddenly may even go away on its own.
For other people who have cardiomyopathy, treatment is needed. Treatment depends on the type of cardiomyopathy you have, how severe the symptoms and complications are, and your age and overall health.
The main goals of treating cardiomyopathy are to:
- Manage any conditions that cause or contribute to the disease
- Control signs and symptoms so that you can live as normally aspossible
- Stop the disease from getting worse
- Reduce complications and the chance of sudden cardiac arrest(SCA)Treatments may include lifestyle changes, medicines, surgery, implanted devices to correct arrhythmias, and a nonsurgical procedure.Lifestyle changesYour doctor may suggest lifestyle changes to manage a condition that’s causing your cardiomyopathy. These changes can help reduce symptoms.Healthy diet and physical activityA healthy diet and physical activity are part of a healthy lifestyle. A healthy diet includes a variety of fruits, vegetables, and grains; half of your grains should come from whole-grain products.Choose foods that are low in saturated fat, trans fat, and cholesterol. Healthy choices include lean meats, poultry without skin, fish, beans, and fat-free or low-fat milk and milk products.Choose and prepare foods with little sodium (salt). Too much salt can raise your risk for high blood pressure. Recent studies show that following the Dietary Approaches to Stop Hypertension (DASH) eating plan can lower blood pressure.Choose foods and beverages that are low in added sugar. If you drink alcoholic beverages, do so in moderation.Aim for a healthy weight by staying within your daily calorie needs. Balance the calories you take in with the calories you use while doing physical activity. Be as physically active as you can.Some people should get medical advice before starting or increasing physical activity. For example, talk to your doctor if you have a chronic (ongoing) health problem, are on medicine, or have symptoms such as
chest pain, shortness of breath, or dizziness. Your doctor can suggest types and amounts of physical activity that are safe for you.
Your doctor can help you decide what kind of eating plan and physical activity are right for you.
Other lifestyle changes
Your doctor also may recommend other lifestyle changes, such as:
- Quitting smoking
- Losing excess weight
- Avoiding the use of alcohol and illegal drugs
- Getting enough sleep and rest
- Reducing stress
- Treating underlying conditions, such as diabetes and high bloodpressureMedicinesA number of medicines are used to treat cardiomyopathy. Your doctor may prescribe medicines to:
- Lower your blood pressure. ACE inhibitors, angiotensin II receptor blockers, beta blockers, and calcium channel blockers are examples of medicines that lower blood pressure.
- Slow your heart rate. Beta blockers, calcium channel blockers, and digoxin are examples of medicines that slow the heart rate. Beta blockers and calcium channel blockers also are used to lower blood pressure.
- Keep your heart beating with a normal rhythm. These medicines help prevent arrhythmias.
- Balance electrolytes in your body. Electrolytes are minerals that help maintain fluid levels and acid-base balance in the body. They also help muscle and nerve tissues work properly. Abnormal electrolyte levels may be a sign of dehydration (lack of fluid in your body), heart failure, high blood pressure, or other disorders. Aldosterone blockers are an example of a medicine used to balance electrolytes.
- Remove excess fluid and sodium (salt) from your body. Diuretics, or “water pills,” are an example of a medicine that helps remove excess fluid and sodium from the body.
- Prevent blood clots from forming. Anticoagulants, or “blood thinners,” are an example of a medicine that prevents blood clots. Blood thinners often are used to prevent blood clots from forming in people who have dilated cardiomyopathy.
- Reduce inflammation. Corticosteroids are an example of a medicine used to reduce inflammation.SurgerySeveral different types of surgery are used to treat cardiomyopathy. These include septal myectomy, implanted devices to help the heart work better, and heart transplant.Septal MyectomySeptal myectomy is open-heart surgery. It’s used for people who have hypertrophic obstructive cardiomyopathy and severe symptoms. This surgery generally is used for younger patients and for people whose medicines aren’t working well.During the surgery, a surgeon removes part of the thickened septum that’s bulging into the left ventricle. This improves blood flow through the heart and out to the body. The removed tissue doesn’t grow back.The surgeon also can repair or replace the mitral valve at the same time (if needed). Septal myectomy often is successful and allows you to return to a normal life with no symptoms.Surgically implanted devicesSurgeons can place several types of devices in the heart to help it work better. One example is a pacemaker. This is a small device that’s placed under the skin of your chest or abdomen to help control abnormal heart rhythms. The device uses electrical pulses to prompt the heart to beat at a normal rate.Sometimes doctors choose to use a biventricular pacemaker. This device coordinates contractions between the heart’s left and right ventricles.
A left ventricular assist device (LVAD) helps the heart pump blood to the body. An LVAD can be used as a long-term therapy or as a short-term treatment for people who are waiting for a heart transplant.
An implantable cardioverter defibrillator (ICD) helps control life-threatening arrhythmias, which may lead to SCA. This small device is implanted in the chest or abdomen and connected to the heart with wires.
If an ICD senses a dangerous change in heart rhythm, it will send an electric shock to the heart to restore a normal heartbeat.
For this surgery, a doctor replaces a person’s diseased heart with a healthy heart from a deceased donor. Heart transplant is a last resort treatment for people who have end-stage heart failure. “End-stage” means the condition has become so severe that all treatments, other than heart transplant, have failed.
Doctors may use a nonsurgical procedure called alcohol septal ablation to treat cardiomyopathy.
For this procedure, your doctor injects ethanol (a type of alcohol) through a catheter into the small artery that supplies blood to the thickened area of heart muscle. The alcohol kills cells, and the thickened tissue shrinks to a more normal size.
This allows blood to flow freely through the ventricle, and symptoms improve.
How can Cardiomyopathy be prevented?
You can’t prevent inherited types of cardiomyopathy. However, you can take steps to lower your risk for conditions that may lead to or complicate cardiomyopathy, such as coronary artery disease, high blood pressure, and heart attack.
Your doctor may advise you to make lifestyle changes, such as following a healthy diet and doing physical activity.
Living with Cardiomyopathy
Some people who have cardiomyopathy—especially those who have the hypertrophic type—may live a healthy life with few problems or symptoms. Others may have serious symptoms and complications.
If you have cardiomyopathy, you can take steps to take care of your heart. Lifestyle changes and ongoing care can help you manage your disease.
A healthy diet and physical activity are part of a healthy lifestyle. Your doctor can help you decide what kind of eating plan is right for you.
Talk with your doctor about the amounts and types of fluids that are safe and healthy for you. Your doctor also may suggest a diet that’s low in sodium (salt) and fat.
Talk with your doctor about the amount and type of physical activity that’s right for you. People who have hypertrophic cardiomyopathy shouldn’t do vigorous exercise. However, moderate exercise, such as walking, often is a good idea.
Your doctor also may recommend other lifestyle changes, such as:
- Quitting smoking
- Losing excess weight
- Avoiding the use of alcohol and illegal drugs
- Getting enough sleep and rest
- Reducing stress
Implantable cardioverter defibrillators (ICDs) are used in children, teens, and adults. Your doctor may recommend an ICD if you’re at risk for certain types of arrhythmia.
ICDs are used to treat life-threatening ventricular arrhythmias, such as those that cause the ventricles to beat too fast or quiver. You may be considered at high risk for a ventricular arrhythmia if you:
- Have had a ventricular arrhythmia before
- Have had a heart attack that has damaged your heart’s electricalsystemDoctors often recommend ICDs for people who have survived sudden cardiac arrest (SCA). They also may recommend them for people who have certain heart conditions that put them at high risk for SCA.For example, some people who have long QT syndrome, Brugada syndrome, or congenital heart disease may benefit from an ICD, even if they’ve never had ventricular arrhythmias before.Some people who have heart failure may need a CRT-D device. This device combines a type of pacemaker called a cardiac resynchronization therapy (CRT) device with a defibrillator. CRT-D devices help both ventricles work together. This allows them to do a better job of pumping blood out of the heart.
Cardiac resynchronization therapy (CRT) is a relatively new therapy for patients with symptomatic heart failure resulting from systolic dysfunction. CRT is only one aspect of the treatment of patients with heart failure.
Briefly, CRT is achieved by simultaneously pacing both the left and right ventricles. Theoretically, biventricular pacing resynchronizes the timing of global left ventricular depolarization and as a result improves mechanical contractility and mitral regurgitation. Several recently published clinical trials demonstrated clinical improvement when selected patients with systolic ventricular dysfunction and heart failure were treated with CRT.
Mechanism of Action for CRT
Conduction delay, as manifested by a prolonged QRS complex duration, is common among patients with systolic dysfunction and heart failure and is associated with an increased prevalence of mechanical dyssynchrony, as opposed to patients with a narrow QRS complex. Cardiac dyssynchrony results in a decrease in stroke volume, facilitation of mitral regurgitation, increased wall stress, and delayed relaxation. The primary objective of CRT is restoration of a more normal ventricular activation pattern. Secondarily, CRT allows optimization of the atrioventricular interval for patients in sinus rhythm.
Compared with the delayed activation that occurs in the setting of an interventricular conduction delay, CRT depolarizes the left ventricle earlier. CRT is believed to reverse the deleterious effects of dyssynchronous ventricular activation by decreasing the electromechanical delay associated with an interventricular conduction delay and providing near-simultaneous contraction of the ventricular septum and the left ventricular free wall.
Numerous clinical investigations have demonstrated that in selected patients CRT significantly improves cardiac output, systolic pressure, maximal rate of pressure rise, the magnitude of wall contraction, mitral regurgitation, and left atrial pressure.
To a much lesser degree than biventricular pacing, optimization of the atrioventricular interval for patients in sinus rhythm may improve cardiac hemodynamics by coordinating the timing of atrial systole relative to ventricular filling.
Benefits of CRT
CRT has been shown to improve functional status as demonstrated by the 6-minute walk test, peak oxygen uptake, the New York Heart Association (NYHA) classification system, and health-related quality of life as assessed by the Minnesota Living with Heart Failure questionnaire. As with most therapeutic interventions, not all patients improve with CRT.
CRT demonstrated a significant reduction in the combined end point of all- cause mortality and hospitalization. In addition, when CRT is combined with a device that has defibrillation capabilities, total mortality is reduced.
Patient Selection for CRT
In general, the CRT trials included patients with sinus rhythm, a QRS complex duration >120 to 130 ms, heart failure resulting from systolic dysfunction with NYHA class III or IV symptoms, and optimal medical treatment for heart failure, including β-blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and diuretics.
On the basis of the inclusion criteria and the results of these studies, a high level of evidence supports CRT in patients with systolic dysfunction and heart failure resulting from either ischemic or nonischemic cardiomyopathy who have a left ventricular ejection fraction (pumping ability) ≤ 35%, are in NYHA functional class III or IV, are on maximal medical therapy, have a QRS complex duration >120 ms, and are in normal sinus rhythm.
Risks and Complications of CRT
The risks associated with the implantation of a CRT device are relatively small and are similar to the risks and complications associated with the transvenous implantation of a conventional permanent pacemaker or implantable defibrillator. These risks include bleeding (≈1%); infection (≈1%); hematoma (≈1%); pneumothorax (≈1%); pericardial effusion with or without tamponade (≈1%); and myocardial infarction, stroke, and death (≈1/500). Transvenous implantation of a left ventricular lead for CRT is accomplished via the coronary sinus and its tributaries. The specific risks associated with implantation of a left ventricular lead for CRT include coronary sinus dissection and perforation (≈1%), lead dislodgment (≈5%), extracardiac stimulation (≈5%), and the risks associated with intravenous contrast, including acute renal failure (<1%).Limited data suggest that ventricular proarrhythmia may be a rare but potential risk of CRT.
Wolff–Parkinson–White syndrome (WPW) is one of several disorders of the conduction system of the heart that are commonly referred to as pre- excitation syndromes. WPW is caused by the presence of an abnormal accessory electrical conduction pathway between the atria and the
ventricles. Electrical signals traveling down this abnormal pathway (known as the bundle of Kent) may stimulate the ventricles to contract prematurely, resulting in a unique type of supraventricular tachycardia referred to as an atrioventricular reciprocating tachycardia.
The prevalence of WPW is between 0.1% and 0.3% in the general population. Sudden cardiac death in people with WPW is rare (incidence of less than 0.6%), and is usually caused by the propagation of an atrial tachydysrhythmia (rapid and abnormal heart rate) to the ventricles by the abnormal accessory pathway.
People with WPW are usually asymptomatic. However, the individual may experience palpitations, dizziness, shortness of breath, or syncope (fainting or near fainting) during episodes of supraventricular tachycardia. The telltale “delta wave” may sometimes—but not always—be seen on an electrocardiogram.
People with WPW who are experiencing tachydysrhythmias may require synchronized electrical cardioversion if they are demonstrating severe signs or symptoms (for example, low blood pressure or lethargy with altered mental status). If they are relatively stable, pharmacologic treatment may be used.
People with atrial fibrillation and rapid ventricular response are often treated with amiodarone] or procainamide to stabilize their heart rate. Procainamide, amiodarone, and cardioversion are now accepted treatments for conversion of tachycardia found with WPW.
AV node blockers should be avoided in atrial fibrillation and atrial flutter with WPW or history of it; this includes adenosine, diltiazem, verapamil, other calcium channel blockers and beta blockers. They can exacerbate the syndrome by blocking the heart’s normal electrical pathway (therefore favoring 1:1 atrial to ventricle conduction through the pre-excitation pathway, potentially leading to unstable ventricular arrhythmias).
The definitive treatment of WPW is a destruction of the abnormal electrical pathway by radiofrequency catheter ablation. This procedure is performed by cardiac electrophysiologists. Radiofrequency catheter ablation is not performed in all individuals with WPW because there are inherent risks involved in the
procedure. When performed by an experienced electrophysiologist, radiofrequency ablation has a high success rate. Findings from 1994 indicate success rates of as high as 95% in people treated with radiofrequency catheter ablation for WPW. If radiofrequency catheter ablation is successfully performed, the condition is generally considered cured. Recurrence rates are typically less than 5% after a successful ablation. The one caveat is that individuals with underlying Ebstein’s anomaly may develop additional accessory pathways during progression of their disease.
A nuclear stress test measures blood flow to your heart muscle both at rest and during stress on the heart. It’s performed similarly to a routine exercise stress test, but provides images that can show areas of low blood flow through the heart and areas of damaged heart muscle.
A nuclear stress test usually involves taking two sets of images of your heart — one set during an exercise stress test while you’re exercising on a treadmill or stationary bike, or with medication that stresses your heart, and another set while you’re at rest. A nuclear stress test is used to gather information about how well your heart works during physical activity and at rest.
You may be given a nuclear stress test if your doctor suspects you have coronary artery disease or another heart problem, or if an exercise stress test alone wasn’t enough to pinpoint the cause of symptoms such as chest pain or shortness of breath. A nuclear stress test may also be recommended in order to guide your treatment if you’ve already been diagnosed with a heart condition.
Your doctor may recommend a nuclear stress test to:
• Diagnose coronary artery disease. Your coronary arteries are the major blood vessels that supply your heart with blood, oxygen and nutrients. Coronary artery disease is a condition that develops when these arteries become damaged or diseased — usually due to a buildup of deposits called plaques. If you have symptoms such as
shortness of breath or chest pains, a nuclear stress test can help
determine if they are related to coronary artery disease.
- Look at the size and shape of your heart. The images from anuclear stress test can show your doctor if your heart is enlarged andcan measure the pumping function (ejection fraction) of your heart.
- Guide treatment of heart disorders. If you’ve already beendiagnosed with coronary artery disease, arrhythmia or another heart condition, a nuclear stress test can help your doctor find out how well treatment is working to relieve your symptoms. It may also be used to help establish the right treatment plan for you by determining how much exercise your heart can handle.A nuclear stress test is generally safe, and complications are rare. But, as with any medical procedure, it does carry a risk of complications.Potential complications include:
- Allergic reaction. It’s possible you could be allergic to the radioactive dye that’s injected into a vein in your hand or arm during a nuclear stress test.
- Low blood pressure. Blood pressure may drop during or immediately after exercise and cause dizziness. It usually goes away when you stop exercising.
- Abnormal heart rhythms (arrhythmias). Arrhythmias brought on by an exercise stress test usually go away shortly after you stop exercising. Life-threatening arrhythmias are rare and usually occur in individuals with severe heart disease.
- Heart attack (myocardial infarction). Although very rare, it’s possible that a nuclear stress test could cause a heart attack.
- Flushing sensation or chest pain. These symptoms can occur when you are given a medication to stress your heart if you’re unable to exercise adequately. These symptoms are usually brief, but tell your doctor if you experience them.
- You may be asked not to eat, drink or smoke for two hours before a nuclear stress test. You can take your medications as usual, unless your doctor tells you not to.
- If you use an inhaler for asthma or other breathing problems, bring it with you to the test. Make sure your doctor and the health care team member monitoring your stress test know that you use an inhaler.
- Wear or bring comfortable clothes with you to the exercise stress test.
When you arrive for your nuclear stress test, your doctor asks you about your medical history and how often you typically exercise. This helps determine the amount of exercise that’s appropriate for you during the stress test.
During a nuclear stress test
Before you start the test, a member of your health care team places sticky patches (electrodes) on your chest, legs and arms. The electrodes are connected by wires to an electrocardiogram (ECG or EKG) machine. The electrocardiogram records the electrical signals that trigger your heartbeats. A blood pressure cuff is placed on your arm to check your blood pressure during the test.
If you’re unable to exercise adequately, you may be injected with a medication that increases blood flow to your heart muscle — simulating exercise — for the test.
You then begin walking on the treadmill or pedaling the stationary bike slowly. As the test progresses, the speed and incline of the treadmill increases. A railing is provided on the treadmill that you can use for balance, but don’t hang on to it tightly, as that may skew the results of the test. On a stationary bike, the resistance increases as the test progresses, making it harder to pedal.
The length of the test depends on your physical fitness and symptoms. The goal is to have your heart work hard for about eight to 12 minutes in order to thoroughly monitor its function. You continue exercising until your heart rate has reached a set target, you develop symptoms that don’t allow you to continue or warning signs are detected by those monitoring your test, including:
- Moderate to severe chest pain
- Severe shortness of breath
- Abnormally high or low blood pressure
- An abnormal heart rhythm
- DizzinessYou may stop the test at any time if you are too uncomfortable to continue exercising.
Injection of dye
Once you’ve reached your maximum level of exercise, a radioactive dye called thallium or sestamibi (Cardiolite) is injected into your bloodstream through an intravenous (IV) line, usually in your hand or arm. This substance mixes with your blood and travels to your heart. A special scanner similar to an X-ray machine — which detects the radioactive material in your heart — creates images of your heart muscle. Inadequate blood flow to any part of your heart will show up as a light spot on the images because not as much of the radioactive dye is getting there.
After exercising, you’ll be asked to rest for two to four hours. During this time, you shouldn’t eat or drink anything or do any strenuous activities. After this time, you’ll have a second set of images taken of your heart while you lie on an examination table. Again, a technician will inject radioactive dye through an IV and will take images of your heart. This second set of images will let your doctor compare the blood flow through your heart while you’re exercising and at rest.
After a nuclear stress test
When your nuclear stress test is complete, you may return to your normal activities for the remainder of the day.
A stress test, sometimes called a treadmill test or exercise test, helps a doctor find out how well your heart handles work. As your body works harder during the test, it requires more oxygen, so the heart must pump more blood. The test can show if the blood supply is reduced in the arteries that supply the heart. It also helps doctors know the kind and level of exercise appropriate for a patient.
A person taking the test
- is hooked up to equipment to monitor the heart.
- walks slowly in place on a treadmill. Then the speed is increased fora faster pace and the treadmill is tilted to produce the effect of going up a small hill.
- may be asked to breathe into a tube for a couple of minutes.
- can stop the test at any time if needed.
- afterwards will sit or lie down to have their heart and blood pressurechecked.Heart rate, breathing, blood pressure, electrocardiogram (ECG or EKG), and how tired you feel are monitored during the test.Healthy people who take the test are at very little risk. It’s about the same as if they walk fast or jog up a big hill. Medical professionals should be present in case something unusual happens during the test.A physician may recommend an exercise stress test to:
- Diagnose coronary artery disease
- Diagnose a possible heart-related cause of symptoms such as chestpain, shortness of breath or lightheadedness
- Determine a safe level of exercise
- Check the effectiveness of procedures done to improve coronaryartery circulation in patients with coronary artery disease
- Predict risk of dangerous heart-related conditions such as a heartattack.Depending on the results of the exercise stress test, the physician may recommend more tests such as a nuclear stress test or cardiac catheterization.
An EKG is a simple, painless test that detects and records the heart’s electrical activity. The test shows how fast your heart is beating and its rhythm (steady or irregular).
An EKG also records the strength and timing of electrical signals as they pass through your heart. The test can help diagnose bradycardia and heart block (the most common reasons for needing a pacemaker).
A standard EKG only records the heartbeat for a few seconds. It won’t detect arrhythmias that don’t happen during the test.
Echocardiography (echo) uses sound waves to create a moving picture of your heart. The test shows the size and shape of your heart and how well your heart chambers and valves are working.
Echo also can show areas of poor blood flow to the heart, areas of heart muscle that aren’t contracting normally, and injury to the heart muscle caused by poor blood flow.
A Holter monitor records the heart’s electrical activity for a full 24- or 48- hour period. You wear one while you do your normal daily activities. This allows the monitor to record your heart for a longer time than a standard EKG.
An event monitor is similar to a Holter monitor. You wear an event monitor while doing your normal activities. However, an event monitor only records your heart’s electrical activity at certain times while you’re wearing it.
For many event monitors, you push a button to start the monitor when you feel symptoms. Other event monitors start automatically when they sense abnormal heart rhythms.
You can wear an event monitor for weeks or until symptoms occur.
A tilt table test is used to evaluate the cause of unexplained fainting (syncope). During a tilt table test, you lie on a table that moves from a horizontal to a vertical position. Your heart rate and blood pressure are monitored throughout the tilt table test.
Your doctor may recommend a tilt table test if you’ve had repeated, unexplained episodes of fainting. A tilt table test may also be appropriate to investigate the cause of fainting if you’ve fainted only once, but another episode would put you at high risk of injury due to your work environment, medical history, age or other factors.
Doctors use a tilt table test to help diagnose the cause of fainting. During the test, your blood pressure and heart rate are monitored. You begin by lying flat on a table. Straps are put around your body to hold you in place. Then, the table is tilted to raise your body to a head-up position — simulating a change in position from lying down to standing up. This test allows doctors to evaluate your body’s cardiovascular response to the change in position.
Cardioversion is a medical procedure done to restore a normal heart rhythm for people who have certain types of abnormal rhythms such as atrial fibrillation, atrial flutter, atrial tachycardia, or supraventricular tachycardia.
Cardioversion is most often done by sending electric shocks to your heart through electrodes placed on your chest. Occasionally, your doctor may perform cardioversion using only medications to restore your heart’s rhythm without electric shocks.
Cardioversion is usually a scheduled procedure that’s performed in a hospital, and you should be able to go home the same day as your procedure. For most people, cardioversion quickly restores a normal heart rhythm.