Ask Dr. Pat

Dr. Pat Consults: Abnormal Heart Rhythm—Stay Alert for the Symptoms!

Dr. Patricia Yarberry Allen is a collaborative physician who writes a weekly “Medical Monday” column for Women’s Voices for Change.  (Search our archives for her posts, calling on the expertise of medical specialists, on topics from angiography to vulvar melanoma.)

This week, she asks Dr. Timothy C. Dutta, the cardiology expert on the Medical Advisory Board of Women’s Voices for Change, to answer the perplexed questions of a very healthy yoga teacher who suddenly found herself in the emergency room due to a condition she’d never suspected she had: atrial fibrillation (abnormal heart rhythm).

Dear Dr. Pat:

I am 52 years old and am thin and fit. I am a yoga teacher and don’t have a general doctor.  I sort of go to the doctor every three or four years when I have a problem.

I discovered that I had an increase in thyroid hormone when I was admitted to the emergency department with rapid heartbeat and shortness of breath. I thought I was having a heart attack and almost fainted before the ambulance came. It turns out that I have atrial fibrillation, which was controlled with medication and disappeared after my thyroid condition was treated. Then the atrial fibrillation returned. I have been told that I may need a procedure to get rid of the cause of the atrial fibrillation.

Why did I get this? If my too-much-thyroid-hormone problem was fixed, then why did the atrial fibrillation come back? Why didn’t I know that I had this abnormal heart rhythm before I had to go to the emergency room?

Susan 

Dr. Dutta Responds:

Dear Susan:

Atrial fibrillation is an arrhythmia, or abnormal heart rhythm. Atrial fibrillation is a very common condition, although it is not as publicized as many other heart conditions. It is important that the symptoms, when present, be recognized so that prompt treatment can prevent complications, especially the increased risk of stroke with this condition. All patients undergo testing to try to find a cause. Treatment is divided into three categories: slowing the heart rate, controlling the rhythm, and decreasing the risk of stroke.

The cause of atrial fibrillation in many patients is never discovered. The evaluation involves a search for conditions or diseases external to the heart and causes within the heart itself.

External causes commonly include an overactive thyroid, excessive alcohol intake, electrolyte imbalances, and medications (both illicit and prescription drugs). Other causes come from within the heart, such as an abnormally functioning heart valve, an enlarged heart, or a weakened heart. Most cases, however, do not have an obvious cause, and the atrial fibrillation is just ascribed to older age.

During atrial fibrillation [see the slide show below], two of the four heart chambers do not contract properly. These top chambers of the heart, called the atria, are small chambers that regulate the heart rate and help the big lower chambers, the ventricles, pump. The heart would normally be paced from the atria, but in atrial fibrillation the heart beats too fast, beats irregularly, and the heart rate becomes less connected to the degree of physical activity.

WVFC_Normal._sinus_rhythm_jpgEKG tracing showing normal heart rhythm.

WVFC_AFibEKG tracing showing atrial fibrillation.

During atrial fibrillation, the ventricles continue to pump blood, and the vast majority of patients maintain stable blood pressure. Some patients may feel their heart racing and skipping, and feel short of breath, dizzy, and have chest discomfort. Other patients will have no symptoms at all, and this abnormal rhythm will be incidentally diagnosed during a routine checkup.

cornellArrhythmias: Atrial fibrillation. (Source: Cornell University, Joan and Sanford I. Weill Medical College)

The initial management focuses on treatment to make sure the patient remains stable. This may require medications to slow down the heart rate, or, less often, treatments to get the heart back into normal rhythm. Assessments with bloodwork and an ultrasound of the heart (echocardiogram) help to determine the cause of the arrhythmia. A decision is made early on as to whether the patient needs to be on a blood thinner to reduce the risk of stroke. In cases of overactive thyroid, a blood thinner is often prescribed.

Some hearts go in and out of atrial fibrillation on their own; some will go back into normal rhythm only with a procedure called a cardioversion. Others will not go back to normal rhythm at all. Many patients will do well in the long run to be left in atrial fibrillation, managed with medications to control the heart rate and blood thinners to manage the risk of stroke.

Patients who have too many symptoms from the atrial fibrillation or who cannot tolerate medications to control the rate are candidates for treatments to return the heart to a normal rhythm. This can be done with anti-arrhythmic medications, and now, more and more frequently, with catheter ablation [explained in the slide show below].

Cornell 2Arrythmias: Cather ablation. (Source: Cornell University, Joan and Sanford I. Weill Medical College)

Medications to control the rhythm are often not completely effective, and they can have long-term side effects—ablation is an invasive procedure with some risk of complications. Its effectiveness as a treatment is, fortunately, improving in terms of both safety and efficacy, making it the treatment of choice for more and more cases of atrial fibrillation.

In the case of hyperthyroid-induced atrial fibrillation, much of the management is the same. Hyperthyroidism (overactive thyroid) is a reversible cause of atrial fibrillation, and generally once the thyroid level is normal, the atrial fibrillation will resolve. It is important to remember that atrial fibrillation can lag months behind correction of the thyroid problem, and treatment to prevent stroke from this condition is important until resolution of the atrial fibrillation occurs. If the atrial fibrillation persists after prolonged recovery from successful treatment of hyperthyroidism, then the management of this abnormal rhythm is the same.

When patients are concerned about “fluttering feeling in the chest, heart palpitations or skipped beats,” they should have an evaluation. Treatments are effective, and serious complications can often be prevented.

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