Premature ventricular contractions - PVCs

Premature ventricular contractions (PVCs) are irregular contractions of the lower chamber of the heart. PVCs often make your heart feel like it’s skipping a beat, beating extra hard, or even stopping for a moment. In fact, your heart does none of the three.

A PVC is a premature or early beat that throws the heart out of rhythm for a moment. The heart then pauses briefly so it can get back to a regular, sequential rhythm. That brief pause is often perceived as a skipped beat or momentary stoppage.

The heart’s normal conduction system

The heart is equipped with it’s own natural pacemaker, the sinus node. This node, located in the upper portion of your heart, produces steady, sequential electrical impulses. Each impulse travels through the upper half of your heart (called the atria), then through the heart’s electrical system to the bottom half (the ventricles).

These electrical impulses stimulate the upper and lower portions of your heart to contract, or beat, in a steady rhythm. A PVC occurs when the sinus node loses control for a moment, and the heart muscle does not contract normally.

What causes PVCs?

PVCs may be caused by a number substances or conditions, including:

·        caffeinated beverages, including coffee, tea and soft drinks

·        cigarettes and nicotine

·        excessive stress

·        alcohol

·        anemia, fever or infection

·        lung or thyroid disease

·        electrolyte imbalance (i.e., potassium, magnesium or calcium levels are too high or too low)

·        the use of certain drugs, including decongestants, asthma medications, amphetamines, diet pills and antidepressants

·        heart disease

Should I be concerned about PVCs?

People with normal hearts may experience PVCs for no apparent reason, and with no underlying cause. PVCs themselves are not life-threatening, and will not cause you harm.

They may be of concern, however, when you have several in a row, or for prolonged periods of time. You may experience discomfort, light-headedness or a sense of anxiousness for no apparent reason. You may want to discuss these feelings or symptoms with your doctor.

How can PVCs be managed?

We all have occasional PVCs as we get older. Most of the time, we don’t even realize they occur. For people who experience discomfort, eliminating the use of caffeine, cigarettes, nicotine or alcohol may reduce or stop the PVCs.

In the case of an electrolyte imbalance, regulating potassium, magnesium or calcium levels to a normal range may stop the PVCs. Your doctor may also prescribe medication to supplement the imbalance, or suggest a diet that is high in certain electrolytes.