Pulse Racing

WHEN TO SEE YOUR DOCTOR

* Your pulse rate frequently rises above 100 beats per minute when you're not exerting yourself.

* Your pulse doesn't return to its normal range per minute within five minutes after ceasing vigorous exercise.

* Seek emergency treatment if you're not exerting yourself or emotionally anxious or under stress, and your pulse takes off chaotically at rates well above 100 beats per minute.

What Your Symptom Is Telling You

Hot-rod racers can "tach up" their engines by revving them at super-high revolutions per minute. The human heart can also tach up and rev at high rates—a condition cardiologists call tachycardia. But unlike a Corvette or a Porsche, the heart is built for comfort, not speed. And when your heart puts the pedal to the metal, you can be in for a harrowing ride.

Taken when at rest, a normal adult's pulse can be anywhere from 60 to 100 beats per minute. Anything over 100 is technically defined as a tachycardia. There are many instances during which it is perfectly natural for the heart to be racing out of this "normal" range, according to Joseph P. Ornato, M.D., professor of internal medicine and cardiology at the Medical College of Virginia Hospital of Virginia Commonwealth University in Richmond.

"The heart will always beat faster when it has more work to do and needs to pump more blood and oxygen to the body," he says. "Exercise, emotion, nervousness, a large meal are all common triggers. If you are overweight or out of shape, the heart will need to work harder. And sometimes, a regular pulse slightly above the norm just may be normal for certain individuals, depending on his or her specific body chemistry."

Illnesses or physiological changes in the body also put additional work demands on the heart. These include fever, high or low blood pressure, asthma, anemia, increases in thyroid hormone production and excess adrenaline. And frequently the heart will pound like a jackhammer in response to external stimulants like nicotine, caffeine, prescription and over-the-counter medications and illegal drugs. Severe lack of certain nutrients—notably potassium and the B vitamins—can also send your heart racing. In fact, fad weight-loss diets can get your mineral balance so out of whack that rapid pulse can become a problem.

Rapid pulses are commonly seen in people who have survived a heart attack or who suffer from congestive heart failure. "When the heart is damaged, one of the ways it has to increase its output is to increase its rate," says James Willerson, M.D., professor of cardiology and chairman of internal medicine at the University of Texas Medical School at Houston.

Sometimes a damaged or even a healthy heart can develop defects in its internal electrical system, causing it to send out rapid-fire signals. A frequently seen by-product of these electrical storms is paroxysmal supra-ventricular tachycardia (PSVT)—a sudden but brief acceleration of the heart at up to 200 beats per minute. Doctors view this type of electrical discharge as mostly bark and no bite. It's easily treatable and non-life-threatening.

Other times, the heart fires at super-high velocities, but in crazy, erratic rhythms. This is called atrial fibrillation. Former president George Bush suffered a much-publicized attack of this generally benign and easily treatable pulse rate acceleration while jogging in 1991.

Physicians are most concerned when these rapid rhythm disturbances occur in the lower chambers of the heart (the ventricles). They can fibrillate at rates of several hundred beats per minute, hindering or halting all heart activity. Ventricular rhythm disturbances can lead to sudden cardiac death.

Symptom Relief

It's always a good idea to have any tachycardia checked out by a doctor just to confirm that there is no serious heart problem. When your heart starts taching up, here's how you and your doctor can slam on the brakes.

Just say no. Avoid all the stimulating substances that can send your heart racing to beat the band: foods and beverages containing caffeine (coffee, teas, sodas), alcohol and illegal drugs, says Dr. Ornato. Smoking constricts arteries, making your heart work harder, and nicotine is a powerful stimulant. If you are taking medication, check the label for proper dosages, or ask your doctor if a change is needed.

Give some extra effort. You can stop some episodes of PSVT dead in their tracks by using one of several techniques called vagal maneuvers. If you're prone to tachycardia, review these maneuvers with your doctor to see if they are appropriate for you to try. They work by stimulating the heart's vagal nerves to induce a slower rate. They include:

* Pinching your nose and blowing.

* Coughing and gagging.

* Plunging your face in a bowl of ice water for several seconds.

* Squatting low, tensing up and straining your body as if you're trying to lay an egg.

* Contracting your abdominal muscles and "straining" like you are trying to move your bowels.

Work out and slim down. Losing weight reduces the heart's overall workload. And aerobic exercise improves your cardiovascular fitness by conditioning the heart, lungs and muscles to use oxygen more effectively, says Dr. Willerson. Exercise is also a great anxiety cure.

Avoid fad diets. High-protein powders and quick weight-loss products often have a disturbing side effect, says Mark E. Josephson, M.D., professor of medicine at Harvard Medical School and director of Harvard-Thorndike Electrophysiology Institute and Arrhythmia Services at Beth Israel Hospital in Boston. They make your heart rate zoom, sometimes dangerously. Go on a doctor-supervised program instead.

Ask about slo-mo medications. Cardiologists treat recurring and persistent tachycardias with a variety of heart-slowing drugs, says Jeremy Ruskin, M.D., director of the Cardiac Arrythmia Service at Massachusetts General Hospital in Boston. These include beta blockers, calcium blockers, quinidine, disopyramide and lidocaine.

See also Heartbeat Irregularities