Premature ventricular contractions (sometimes called PVCs or VPCs or benign ventricular ectopics) are a fairly common abnormal heart rhythm (arrhythmia). PVCs are often considered “added” beats that interrupt the normal heartbeat and regular rhythm of the heart.

During a normal heart rhythm, an electrical  impulse is generated in the upper right chamber of the heart (right atrium). It spreads through the heart, causing the upper chambers to contract then the lower chambers (ventricles) to contract. This impulse is generated at a steady, predictable rate, depending on the circumstances.

However, there are other cells throughout the heart that can generate electrical impulses. These cells may take over for the main pacemaker if necessary. Some of them are located in the ventricles. If these cells fire at the wrong time, the electrical impulse they generate will cause the ventricles to contract early, resulting in a premature ventricular contraction. They may be caused by fatigue, caffeine, alcohol, nicotine or a variety of other factors. In many cases, the cause of PVCs is unknown.

The vast majority of PVCs have no symptoms. However, some people may feel a skipped heartbeat or a galloping, rapid heartbeat called a palpitation or experience dizziness. In general, these abnormal beats are harmless, although there are certain patients in whom PVCs may cause more serious problems. In general, these include existing heart patients and those with concurrent cardiac conditions. Even among people without prior heart conditions, diagnosing PVCs and ruling out heart disease may be important. Individuals are urged to contact their physician if they experience chest pain or a sudden worsening of their PVCs. If necessary, treatment generally involves taking medication, such as beta blockers or antiarrhythmics.