Mount Auburn Healthcare Connection

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It is not uncommon to see in the media seemingly healthy athletes who tragically die suddenly during an athletic competition, such as a basketball game or a marathon race. Sudden death is a big problem in the United States, resulting in about 300,000 deaths a year—and most of these deaths are due to arrhythmias.

Panos Voukydis, M.D., Ph.D., cardiologist and arrhythmia specialist at Mount Auburn Hospital, a teaching hospital of Harvard Medical School, says, “It is very important for anyone who feels an irregular heartbeat or a heartbeat that is inappropriately rapid to seek medical attention without any delay.”

Dr. Voukydis describes arrhythmias as disorders of the regular beating of the heart. Many people are aware of such irregularities, but others are not. These irregularities can originate in the heart’s upper or lower chambers. When the heart beats faster than 100 beats per minute, this is called tachycardia. Tachycardia happens to every healthy person who exercises, becomes excited, or has a fever.

When the heart beats slower than 60 beats per minute, this is called bradycardia. Bradycardia is frequently a normal condition in trained athletes or in people taking certain medications. When bradycardia or tachycardia occur inappropriately, this may indicate a problem with the heart rhythm, which can be quite simple or may indicate a serious situation. In extreme cases of tachycardia or bradycardia, the function of the heart is impaired and an inadequate amount of blood is pumped through the heart to the rest of the body, leading to severe weakness, dizziness or fainting. If the situation does not correct itself, something that happens not infrequently, there can be brain damage or even death.

Arrhythmias that occur on a background of a normal heart are frequently benign, unless the heart rate is too slow or too fast. When there is an underlying heart problem, however, such as a previous heart attack, an enlarged heart, or a family history of such problems, even arrhythmias that are not extremely fast or extremely slow may lead to serious problems or even sudden death.

Serious arrhythmias can cause weakness or feeling faint. Frequently, but not always, a person may be aware of an abnormal heartbeat. Arrhythmias sometimes accompany other cardiac conditions, such as blocked arteries or congestive heart failure. Medical conditions that may facilitate the development or heart disease, such as high blood pressure, high cholesterol, smoking and diabetes, contribute indirectly to the development of arrhythmias.

While arrhythmias can occur in any age group, certain types are most common in older adults, because they are more likely to have already damaged hearts.

However, young adults or even children are not immune. Certain families carry defective genes for conditions that may lead to arrhythmias and sudden death at a young age. If you come from a family with members who died suddenly, you need to be evaluated by an arrhythmia specialist. In particular, children who faint need to be checked for genetic heart disorders.

Certain genetic disorders precipitate arrhythmias only under severe physical stress. For this reason, anyone planning to participate in a strenuous sport should be checked for cardiac conditions that could result in an arrhythmia or cardiac arrest during exertion.

A type of irregular heartbeat called atrial fibrillation affects 2.2 million people in the United States or one out of every eight adults over 75 years old. Atrial fibrillation is a relatively common disorder that is fairly benign compared to other types of arrhythmias. During atrial fibrillation, the heart’s upper chambers quiver instead of beating regularly and the lower chambers beat erratically. As a result, blood isn’t pumped out of them efficiently and the result is decreased exercise capacity and a tendency to develop blood clots in the heart, which can migrate to the brain and result in strokes.

Heart arrhythmias can be diagnosed through a variety of methods. In diagnosing arrhythmias, the physician will first take a medical history and perform a complete physical examination. If any heart irregularities are detected, then the person may be referred to an arrhythmia specialist.

If an arrhythmia is suspected, the physician has a variety of options. An electrocardiogram at rest or during exercise can help in diagnosis. Sometimes it is necessary for the person to wear an electronic monitor (Holter monitor) that records heartbeats over 24 hours. This will document the nature of the heart rhythm and will record changes, which may or may not be related to the symptoms. If the symptoms of arrhythmia are infrequent and the Holter monitor does not help with the diagnosis, the physician may recommend the Event Monitor, an electronic recorder that the patient wears for a month.

If a diagnosis has still not been reached or if there is an urgency to make a prompt diagnosis, there is the option of an electrophysiology study. This is a sophisticated test during which electrodes are placed inside the heart to record the arrhythmia directly from the heart, thus obtaining a precise diagnosis that can lead to an effective treatment.

Dr. Voukydis points out that there are a variety of arrhythmias, and each type requires its own treatment. Over the past 10 years there has been a veritable revolution in the ways arrhythmias are treated. Sometimes reassurance is all that is needed. At other times, medications can be quite effective. Ablation is a treatment that has been refined in recent years. This is an invasive procedure, done in conjunction with the electrophysiology study mentioned earlier. Thin, flexible insulated wires are introduced through the veins or the arteries and advanced in the heart. When the mechanism of the arrhythmia is established, the area responsible for the arrhythmia is obliterated either by heating it (radio frequency ablation) or by freezing it (cryoablation). The advantage of ablation is that once it is done successfully, the arrhythmia is cured and no further treatment is necessary.

Another type of treatment involves implanting devices. These are pacemakers for severe slowing of the heartbeat or defibrillators for very rapid heart beat. The defibrillators monitor the heart continually. If an arrhythmia occurs, the device delivers an electrical charge to the heart that re-establishes the normal rhythm. (Vice President Dick Cheney has one of these devices implanted.) These devices are especially effective in individuals with severely damaged hearts who have a tendency to develop fatal arrhythmias.

Defibrillators provide effective treatment for arrhythmias related to damaged hearts. However, it is much better to try to prevent the conditions that cause heart damage, such as high blood pressure, high cholesterol, physical inactivity, and many others. Maintaining general good heart health through good nutrition, exercise, and weight control is always a good idea.

Dr. Voukydis says, “While heart arrhythmias can be very serious and even fatal, there are many extremely effective treatments, but diagnosis is the first step. So if you happen to develop an irregular or unusually rapid heartbeat or if you have a family history of unexpected sudden death, make sure you have your heart checked.”