Medical Edge Newspaper Column

Skipped Heartbeats: Usually, But Not Always, Harmless

Dec. 31, 2006
DEAR MAYO CLINIC:
About three months ago, I had a serious upper-respiratory infection and was treated with a high dose of prednisone. After taking the medication for a month, I developed skipped heartbeats. I have had this problem now for four months and am being given sotalol by my cardiologist, but my heart is still skipping beats. My questions are: Could the prednisone have caused this problem? And what can I take to correct it? -- Shawnee, Okla.

ANSWER:
It is unlikely that prednisone, which no doubt was prescribed to reduce inflammation from the respiratory disease, caused the skipped beats. Short-term use of prednisone or its kindred corticosteroids is known to produce lots of side effects -- such as water retention, weight gain and mood swings -- but skipped heartbeats are rare. Even if prednisone were suspected, the fact that the skipped beats continued for months after you stopped taking the drug is convincing evidence that it was not the cause.

Skipped beats are normal in many individuals and are usually harmless. Consider that your heart beats about 100,000 times a day, and more than 2.5 billion times over the average lifetime. Given that the electrical timing of millions of heart cells must be highly coordinated for the heart to pump blood, it is not surprising that the beats are not always precisely uniform. In fact, the average healthy person experiences some 50 to 100 skipped beats a day, usually without noticing them.

Common causes of skipped beats include anxiety or stress, caffeine from any source, over-the-counter cold remedies containing pseudoephedrine and some asthma medications. In your case, the bout of respiratory infection itself could have been a cause, as could a medication, such as the bronchodilator albuterol, if it was used to treat you.

While this kind of arrhythmia is usually harmless, sometimes it can indicate a serious underlying problem, such as an abnormality of the heart's electrical system, a heart valve or heart muscle abnormality, or an inflammation of the heart. These conditions not only can cause skipped beats but also dizziness, shortness of breath, weakness, chest discomfort, and fainting. If you experience any of these symptoms, it's time to see a doctor for further investigation.

A physician can perform heart-monitoring tests that either passively monitor your heart or actively try to induce, and then observe, an arrhythmia. The passive tests may include an electrocardiogram, a Holter monitor (a portable ECG device worn for a day or more to record your heart's activity as you go about your usual routine), or an echocardiogram (in which a hand-held device placed on your chest uses sound waves to produce images of your heart's size, structure, motion and function). Active tests, if needed, may include a stress test, tilt-table test, or more invasive procedures such as electrophysiologic testing of the electrical pathways within the heart.

If a heart abnormality is found to be causing the skipped beats, this problem can be addressed by an anti-arrhythmic medication, which usually works by slowing the heart rate. A wide variety of drugs are possible options, with selection based on the precise nature of the abnormality; they include calcium channel blockers, potassium channel blockers and digitalis. Beta-blockers, such as sotalol, were widely used in the past, but with the availability of improved agents they are no longer the usual treatment of choice.

The cause of your problem, and the way to treat it, can only be determined after comprehensive examination and study. Given the overall statistics on skipped beats, it is quite possible that yours derive from a benign cause and the main "treatment" will consist of simple reassurance and, perhaps, advice to go easier on the coffee.

-- Bijoy K. Khandheria, M.D., Cardiovascular Diseases, Mayo Clinic, Scottsdale, Ariz.