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Premature Ventricular Complexes - PVCs

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Updated June 02, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Among the many different types of cardiac arrhythmias, few have created as much consternation and confusion - among both doctors and patients - as premature ventricular complexes (PVCs, also called premature ventricular contractions). In various doctors’ offices, and at various points in history, PVCs have been regarded as either harbingers of impending death or as completely benign phenomena that require no attention whatsoever.

The right answer is somewhere in between these two extremes. To really understand the significance of PVCs, we need to review what they are, what they imply in terms of medical prognosis, how they ought to be evaluated and how they ought to be treated.

What Are PVCs?

A PVC is an extra electrical impulse arising from one of the cardiac ventricles, usually the left ventricle. Because this early impulse appears before the next normal heart beat has a chance to occur, it is called "premature." PVCs are diagnosed by observing them on an electocardiogram. PVCs are quite common. Around one in 20 normal people will have at least one PVC on a two-minute ECG strip, and a much higher percentage will have PVCs on 24-hour Holter monitoring.

Some people will have episodes of several PVCs in a row. If there are more than three PVCs in a row, the episode is called non-sustained ventricular tachycardia (NSVT).

Symptoms With PVCs

Most people with PVCs have no symptoms at all. They simply don't feel them. However, a substantial minority of people with PVCs will perceive palpitations - an unusual awareness of the heart beat. These palpitations are often described as "skipped beats" or a "pounding heart." In some people, these symptoms are extremely difficult to tolerate.

Whether or not you perceive symptoms from your PVCs is related to many factors. Some people are just naturally more sensitive to any unusual events that occur in their internal organs - including PVCs. Others are blissfully unaware of their PVCs during the day when they are active and distracted, but suddenly begin to feel them when they retire for the night and external stimuli are removed. But fortunately, most people do not feel their PVCs at all.

Why Are PVCs Significant?

PVCs have medical significance beyond the fact that they can produce symptoms. Over the years, the chief concern about PVCs is the idea that they may increase a person's risk for sudden death from cardiac arrest. For decades, it was believed that the presence of PVCs significantly elevated that risk. More recent evidence has suggested that PVCs themselves probably do not increase the risk of sudden death very much (if at all), and that the association between PVCs and sudden death may be an indirect one.

Specifically, it turns out that people who have frequent PVCs are more likely to have, or to develop within a few years, significant underlying heart disease. And since people with significant heart disease do indeed have a higher risk of sudden death, PVCs are therefore associated with that same risk (whether or not the PVCs themselves actually produce the increased risk).

So - PVCs may be associated with increased cardiac risk, but are probably not the actual cause of that increased risk.

How Should PVCs Be Evaluated?

To reiterate, the chief medical significance of PVCs is that they may be associated with an increased risk of heart disease. So if you have PVCs, your doctor should launch a cardiac evaluation, looking for previously unknown heart disease, and assessing your risk of developing heart disease in the future.

The heart diseases most often associated with PVCs include coronary artery disease (CAD) and heart failure due to dilated cardiomyopathy. PVCs are also commonly seen with hypertrophic cardiomyopathy, and with heart valve disease.

In general, an echocardiogram is a good way to screen for most of these cardiac conditions, although your doctor may also want to perform a stress thallium test to check more rigorously for CAD.

In addition, you and your doctor should go through a formal risk assessment including evaluating your diet, weight, smoking history, exercise habits, cholesterol and triglyceride levels, blood pressure and blood glucose evaluation.

Aren't the PVCs Themselves Dangerous?

The best information we have today suggests that PVCs themselves are only rarely dangerous. In fact, studies have shown that suppressing PVCs with antiarrhythmic drugs not only fails to reduce the risk of dying, but in fact (depending on which drug is used), may increase that risk.

So only rarely is it ever medically necessary, or even desirable, to attempt to get rid of the PVCs.

Treating People with PVCs

Since PVCs themselves are thought not to be particularly dangerous, it should not be a surprise that treating PVCs isn't entirely a straightforward endeavor. In fact, doctors often get a little confused about what they are supposed to do when one of their patients has PVCs - especially when those PVCs are producing a lot of symptoms.

Generally, the treatment of PVCs aims to do two things. The first and most important goal is to reduce the overall cardiac risk, including the risk of sudden death. The second goal, of course, is to reduce the symptoms (if any) being caused by the PVCs. These are two entirely different goals, and as doctors and patients make decisions about treating PVCs, each of these treatment goals needs to be addressed independently.

Sources:

Zipes, DP, Camm, AJ, Borggrefe, M, et al. ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death-Executive Summary A Report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death). J Am Coll Cardiol 2006; 48:1064.

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