Premature Ventricular Contractions (PVCs, PVC)

  • Medical Author:
    Daniel Lee Kulick, MD, FACC, FSCAI

    Dr. Kulick received his undergraduate and medical degrees from the University of Southern California, School of Medicine. He performed his residency in internal medicine at the Harbor-University of California Los Angeles Medical Center and a fellowship in the section of cardiology at the Los Angeles County-University of Southern California Medical Center. He is board certified in Internal Medicine and Cardiology.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

What are premature ventricular contractions (PVCs)?

Premature ventricular contractions (PVCs, PVC) 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 sinoatrial (SA) node, the atrioventricular (AV) 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 to 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 to 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, causing them to contract. Continue Reading

Picture of the cross section of the heart
Picture of the cross section of the heart.
Reviewed on 3/23/2016
References
REFERENCES:

"Sudden Cardiac Arrest." Cleveland Clinic. March 2010.

Simpson, R. J. Jr., et al. "Prevalence of premature ventricular contractions in a population of African American and white men and women: the Atherosclerosis Risk in Communities (ARIC) study." American Heart Journal 143.3 (2002): 535-540.

Zipes, Douglas P. and Hein J. J. Wellens. "Sudden cardiac death." Circulation 98.21 (1998): 2334-2351.

Medically reviewed by Robert J. Bryg, board certified in internal medicine with a subspecialty in cardiovascular disease.

IMAGES:

1.iStock

2.MedicineNet

3.MedicineNet

4.iStock / Getty

Subscribe to MedicineNet's Heart Health Newsletter

By clicking Submit, I agree to the MedicineNet's Terms & Conditions & Privacy Policy and understand that I may opt out of MedicineNet's subscriptions at any time.

VIEW PATIENT COMMENTS
  • Premature Ventricular Contractions (PVCs) - Symptoms

    Please describe the symptoms of your premature ventricular contractions.

    Post View 40 Comments
  • Premature Ventricular Contractions (PVCs) - Causes

    What was the cause of your premature ventricular contractions?

    Post View 41 Comments
  • Premature Ventricular Contractions (PVCs) - Experience

    Have you ever experienced PVCs? Please describe your experience.

    Post View 13 Comments
  • Premature Ventricular Contractions (PVCs) - Treatment

    What treatments or lifestyle changes did you find effective for your PVCs?

    Post View 10 Comments

Health Solutions From Our Sponsors