MedicineNet

Premature Ventricular Contractions
(PVCs)

Medical Author:
Medical Author:
Medical Editor:

Featured premature ventricular contractions patient discussions on symptoms experienced

"I have had PVCs for about 15 years. (I am now 48.) They go away with exercise and return on resting phases. Emotional stress and coffee seem to increase the frequency. I suffer from migraines as well. Wine and stress seem to be triggers too. I can go long periods without any PVCs if coffee and stress aren?t there. I have had echocardiograms, EKGs, cholesterol tests, advanced cardiac disease screens, and they all say the heart is healthy. The cardiologist says many healthy people have them. Getting them checked out can rule out any PVCs that are risky. "

"I am a 28-year-old female that is healthy and found out about my heart condition when I was 17. This past year my condition has worsened. I have had every test done out there, so I know what that is like. I had the Holter Monitor done about a month ago and they found out that I had 8,690 PVCs within a 24-hour period. That is beyond severe. I am always tired, always sick, feel like I can't breathe very well and my chest feels like it's going to explode sometimes. Very scary! I haven't been to a cardiologist in a long time, but my doctor is finally making me go again to get this checked out."

What are premature ventricular contractions?

Premature ventricular contractions (PVCs) are premature heartbeats originating from the ventricles of the heart. Premature ventricular contractions are premature because they occur before the regular heartbeat.

Normal function of the heart

The heart has four chambers. The upper two chambers are the atria, and the lower two chambers are the ventricles.

  • The atria deliver blood to the ventricles, and the ventricles deliver blood to the lungs and to the rest of the body.

  • The right ventricle delivers blood to the lungs while the left ventricle delivers blood to the rest of the body.

  • The heartbeat (pulse) that we feel is caused by the contraction of the ventricles.

The heartbeat is normally controlled by the electrical system of the heart. The electrical system of the heart consists of the SA node (sino-atrial node), the AV node (atrio-ventricular node) and special tissues in the ventricles that conduct electricity.

The SA node is the heart's electrical pacemaker. It is a small patch of cells located in the wall of the right atrium; the frequency with which the SA node discharges electricity determines the rate at which the heart normally beats. The SA node keeps the heart beating in a regular manner. At rest, the frequency of the electrical discharges originating from the SA node is low, and the heart beats at the lower range of normal (60-80 beats/minute). During exercise or excitement, the frequency of discharges from the SA node increases, increasing the rate at which the heart beats. In people who exercise regularly, the resting heart rate may be below 50-60 and is not of concern.

The electrical discharges pass from the SA node, through the special tissues of the atria into the AV node, and through the AV node to the special conduction tissues of the ventricles and causing the ventricles to contract.

Picture of the Heart - Left and Right Atrium, Left and Right Ventricles, and Other Portions of the Heart

Picture of the Cross Section of the Heart

What happens during a premature ventricular contraction?

During a premature ventricular contraction, the ventricle electrically discharges (and contracts) prematurely before the normal electrical discharges arrive from the SA node. These premature discharges are due to electrical "irritability" of the heart muscle of the ventricles and can be caused by heart attacks, electrolyte imbalances, lack of oxygen, or medications. Immediately after a premature ventricular contraction, the electrical system of the heart resets. This resetting causes a brief pause in heartbeat, and some patients report feeling the heart briefly stopping after a premature ventricular contraction.

How common are premature ventricular contractions?

Premature ventricular contractions are common. Many people have premature ventricular contractions without any symptoms. Premature ventricular contractions may be more common among older patients, patients with high blood pressure, and patients with heart disease. Premature ventricular contractions can also occur in young healthy individuals without heart disease or high blood pressure.



Patient Comments

Viewers share their comments

Premature Ventricular Contractions (PVCs) - Causes Question: What was the cause of your premature ventricular contractions?
Premature Ventricular Contractions - Symptoms Experienced Question: Please describe the symptoms of your premature ventricular contractions.