Harvard Heart Letter

When the heart “skips a beat,” flip-flops, or flutters

Brief heart rhythm disruptions are usually harmless. But occasionally, they signal a more serious condition.

You probably don’t notice your heartbeat most of the time. But what if you suddenly realize that it’s beating more forcefully or faster than usual? These odd sensations are known as palpitations — an awareness of a strong, rapid, or irregular heartbeat. Palpitations are among the most common reasons people see a doctor.

“I actually try to avoid the term palpitations,’ because it’s a generic term that can be misleading,” says Dr. William Sauer, chief of the Cardiac Arrhythmia Service at Harvard-affiliated Brigham and Women’s Hospital. Sometimes, what people really mean is chest discomfort, he says, which could be serious and should be evaluated right away if it lasts more than a few minutes. And if you have any unusual heart sensations accompanied by other symptoms, such as dizziness or breathlessness, seek medical attention right away.

Early (not skipped) beats

But occasional, brief hiccups in the heart’s normal rhythm are rarely cause for concern. One common cause of what people perceive as a skipped beat occurs when the heart’s upper chambers (atria) squeeze a fraction of a second earlier than they should — a so-called premature atrial contraction. The atria then pause an instant longer afterward to get back into a normal rhythm. The heart’s lower chambers (ventricles) then contract forcefully as they clear out the extra blood that accumulates during the pause. The pause feels as though the heart has skipped a beat.

The heart’s ventricles can also contract earlier than usual, something known as a premature ventricular contraction. These may feel as though the heart has briefly stopped and restarted, causing a pounding or flip-flopping sensation, says Dr. Sauer. Doctors also refer to both types of premature contractions as ectopic beats (ectopic refers to an abnormal place or position). If you have these only once in a while and are otherwise healthy, there’s no need to consult a doctor.

A rapid heartbeat

But sometimes, fleeting abnormal heart rhythms (arrhythmias) need to be checked out. A fluttering sensation in the chest may suggest an unusually fast heart rate. If this happens with no explanation (such as exercise or anxiety), an electrical misfire in the upper part of the heart may be to blame. The most common is atrial fibrillation, a rapid, irregular heartbeat that can increase the risk of a stroke. “In some people, the first symptom of atrial fibrillation is an uncomfortable awareness of an irregular heartbeat,” says Dr. Sauer.

Another, less common arrhythmia is known as supraventricular tachycardia, or SVT. This can cause the heart to race as fast as 250 beats per minute or higher, in bouts that last for minutes but sometimes hours. Most of the time, SVT is not dangerous, but it can make people feel lightheaded or dizzy, depending on how long it lasts.

Possible palpitation triggers

  • Anxiety, stress, fear, or panic
  • Exercise
  • Caffeine, nicotine, or alcohol
  • Medical conditions such as an overactive thyroid, low blood sugar, low potassium level, anemia, dehydration
  • Medications such as asthma inhalers, decongestants, and thyroid and anti-arrhythmic drugs

Diagnosing arrhythmias

Because heart misfires tend to come and go, they are rarely detected during a brief recording of the heart’s rhythm (electrocardiogram, or ECG) done in a doctor’s office. “For symptoms that occur every few weeks or so, the best option is a small patch about the size of a Band-Aid that you stick on your chest,” says Dr. Sauer. It can record the heart’s rhythm for up to two weeks. For less frequent symptoms, a person may need to wear a cardiac event monitor for 30 days to capture the episodes of abnormal activity. In rare cases, people with very infrequent but troublesome symptoms get an implantable loop recorder, a tiny device inserted under the skin that wirelessly records the heart’s rhythm for up to three years.

A range of factors can trigger palpitations, including exercise, anxiety, and certain medical conditions and drugs (see “Possible palpitation triggers”). “But avoiding triggers isn’t always possible and may have a limited benefit,” says Dr. Sauer. Even when palpitations don’t signal a serious condition, they can still be bothersome if they occur frequently. When that’s the case, treatment options include medications or catheter ablation, a procedure that creates tiny lesions in the abnormal heart tissue to stop the errant electrical signals.

Image: boonchai wedmakawand/Getty Images

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