Heart palpitations not always a crisis
By the faculty of Harvard Medical School for The Harvard Medical School Adviser

Q: Sometimes my heart feels like it's skipping a beat. Should I be worried?

A: It sounds like you may be having heart palpitations. They are very common. You might feel as though your heart is fluttering, throbbing, flip-flopping, racing or pounding, or that it has missed a beat. Some people feel palpitations as a pounding in the neck; others as just a sense of unease.

For some people, palpitations appear out of the blue and go away just as fast. For others, they are linked with certain activities, events or feelings. Some people notice palpitations when they are drifting off to sleep; others, when they stand up after bending over.

The list of possible causes is long and varied. Some people have palpitations when they exercise, especially as they cool down afterward, or when they are worried or stressed. Getting too much caffeine, chocolate or alcohol, or not enough potassium or water can also spark the problem.

A variety of medications may set off palpitations. Cough and cold remedies, antibiotics, amphetamines, thyroid hormone, digoxin, asthma medications, beta blockers and antiarrhythmics could all be triggers. Dietary supplements, such as ephedra, ginseng, valerian, bitter orange and hawthorn, and drugs, such as nicotine and cocaine, are also culprits.

Palpitations may affect women who are pregnant or menopausal. Or they may be related to a medical condition such as anemia, overactive thyroid, heartburn, mitral valve prolapse or a past heart attack. Even something as simple as swallowing or as common as a fever can trigger palpitations.

Palpitations are worrisome but usually aren't dangerous. Most are caused by a harmless "hiccup" in the heart's rhythm (see illustration). But palpitations can sometimes signal an important problem in the heart or elsewhere in the body.

Sorting out the worrisome palpitations from the harmless ones isn't always easy. A physical exam by a doctor may reveal telltale signs. Your doctor will likely listen to your heart and measure your heart's electrical activity with an electrocardiogram (EKG). Most of the time, the exam doesn't turn up any problems. In some cases, your doctor may ask you to wear a portable monitor to record your heart rhythm at home for 24 to 48 hours or perform other tests. Often, though, even the most thorough search doesn't turn up a correctable cause.

If your palpitations aren't accompanied by dizziness, light-headedness or other symptoms, if you don't have a valve disorder or another structural problem with your heart, and if sudden death or other heart problems aren't lurking in your family tree, to be threatening.

You can help pin down the cause by keeping track of your palpitations. The more details you can marshal, the better. When do they occur? Is your heart rhythm fast or slow? Regular or irregular? Do you feel lightheaded, dizzy or out of breath, or do you have chest pain? Are you usually doing the same thing when they occur? Do they start and stop suddenly, or fade in and out gradually? Your general health, what you eat and drink, the medications, herbs, and supplements you are taking and your family history are also important.

If you have unexplained palpitations, start with the simple things first: Try cutting back on caffeine, smoking or alcohol to see whether they are the problem. Beware of over-the-counter decongestants that contain pseudoephedrine or phenylephrine. If your palpitations happen when you exercise, that doesn't mean you should stop exercising. Instead, it's worth talking with your doctor about having an exercise stress test to look at your heart's response to physical challenges. Make sure you eat regularly (low blood sugar can cause palpitations) and drink plenty of fluids. Get enough sleep.

Doctors can prescribe various drugs to prevent irregular heartbeats, but they tend to have side effects and can even cause serious rhythm problems of their own. For some people, a beta blocker or anti-anxiety medication can ease the problem without causing a new one.

Medications aren't always required. The fix may be as simple as dealing with anemia or a low potassium level, or as complicated as a procedure to destroy a small patch of cells inside the heart that gives rise to erroneous beats. If the problem is stress or anxiety, stress-busting activities like exercise, yoga, or breathing exercises may help keep palpitations away.

Remember that most palpitations are harmless. The hardest part in making them stop may be pinning down their source. If you are having palpitations, keep an eye on dietary and lifestyle habits, and work with your doctor to learn whether you should be a-flutter about your heart's flip-flops.

Copyright 2007 the President and Fellows of Harvard College. Developed by Harvard Health Publications (www.health.harvard.edu). Distributed by UFS. Submit questions to harvard_ adviser@hms.harvard. edu.