Ask the Doctors by Eve Glazier, M.D. and Elizabeth Ko, M.D

Heart Monitor Will Assess Number of PVCs Over 24-Hour Period

Dear Doctor: About 15 years ago, while giving blood, I was advised of an irregularity, which my doctor confirmed after an EKG, known as premature ventricular contractions. He told me not to worry, and I've not had any problems. Now I'm 79 and still in good health, but my current doctor had me wear a heart monitor and has now referred me to a cardiologist. Should I be concerned?

Dear Reader: Premature ventricular contractions (PVCs) are very common. In healthy people without any evidence of heart disease, 50-54 percent will be found to have some degree of PVCs when monitored for 24 hours. Here are the basics: Electrical impulses normally begin in the atria of the heart before they make their way down to the ventricles. This leads to the atria contracting first, followed by the ventricles. However, PVCs are ventricular contractions that bypass the atrial beat, leading to an extra heartbeat.

PVCs are more common in men than in women, increase in frequency with age and are more common in African-Americans. Lastly, they are more common in people with structural heart disease, especially those with congestive heart failure and those who have had heart attacks.

Most PVCs are not felt. It sounds as if you weren't having symptoms from the PVCs, but rather that they were simply noted on examination by your doctor. When patients feel PVCs, they often describe a sensation of a pause or a skipped beat. People also sometimes feel that the heart is beating hard or fast or that they have a strong pulsation in the neck. Sometimes PVCs can cause lightheadedness and anxiety. Very frequent PVCs have been associated with heart failure.

Sometimes, concerns about PVCs are related to their frequency, especially if they were sporadic and then become more numerous. Increased frequency of PVCs has been associated with an increase in mortality. This was illustrated in a 2006 study of 15,070 patients ages 45 to 64 who had no history of heart disease and who had a two-minute electrocardiogram performed. Those with one or more PVCs on the electrocardiogram had twice the likelihood of dying of coronary heart disease.

Similarly, a 2007 study of 45,402 veterans showed that 3.8 percent of the veterans studied had PVCs on a routine electrocardiogram -- and that the PVCs were associated with a nearly twofold increase in mortality. Note that routine electrocardiograms only last for 10 seconds, so detecting a PVC on an electrocardiogram suggests a very high frequency over a 24-hour period.

Studies over a 24-hour period have also shown that more frequent PVCs -- recorded in this way -- are also linked to an increased risk of heart failure and heart-related deaths, but the risk is greater when a PVC is seen on a routine electrocardiogram.

The heart monitor that your doctor recommended should pick up the number of PVCs over a 24-hour period. If the PVCs are frequent, the cardiologist may want to do other studies, like an echocardiogram, to determine whether there is any structural damage to the heart.

Treatment of PVCs for people with symptoms include calcium channel blockers and beta blockers. If these don't help control symptoms or if there is structural heart disease, anti-arrhythmic medication or electrical destruction of the area of heart that is causing PVCs may be necessary.

I would have some degree of concern regarding PVCs, but the results of the 24-hour monitor and your visit to the cardiologist will provide more information.

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