Mayo Clinic Health Manager
Get free personalized health guidance for you and your family.
Get Started
About our e-newsletters
- Free e-newsletters
- Mayo Clinic expertise
- We do not share your e-mail address
Housecall, our weekly general-interest e-newsletter, keeps you up to date on a wide variety of health topics with timely, reliable, practical information, recipes, blogs, questions and answers with Mayo Clinic experts and more. Our biweekly topic-specific e-newsletters also include blogs, questions and answers with Mayo Clinic experts, and other useful information that will help you manage your health.
Housecall Archives
Mayo Clinic Housecall
Stay up to date on the latest health information.
What you get
- Free weekly e-newsletter
- Mayo Clinic expertise
- Recipes, tools and other helpful information
- We do not share your e-mail address
Causes
By Mayo Clinic staff
Your heart is made up of four chambers — two upper chambers (atria) and two lower chambers (ventricles). The rhythm of your heart is normally controlled by the sinoatrial node (SA node) — or sinus node — an area of specialized cells located in the right atrium. This natural pacemaker produces the electrical impulses that trigger the normal heartbeat. From the sinus node, electrical impulses travel across the atria to the ventricles causing them to contract and pump blood out to your lungs and body.
Premature ventricular contractions are abnormal contractions that begin in the ventricles. These extra contractions usually beat sooner than the next regular heartbeat. And they often interrupt the normal order of pumping, which is atria first, then ventricles. As a result, the extra, out-of-sync beats are usually less effective in pumping blood throughout the body.
Why do extra beats occur?
The reasons aren't always clear. Certain triggers, heart diseases or changes in the body can make cells in the ventricles electrically unstable. Underlying heart disease or scarring may also cause electrical impulses to be misrouted. Premature ventricular contractions may be associated with:
- Chemical changes or imbalances in the body
- Certain medications, including common asthma medications
- Alcohol or illegal drugs
- Increased levels of adrenaline in the body, caused by caffeine, exercise or anxiety
- Injury to the heart muscle from coronary artery disease, congenital heart disease, high blood pressure or infections (myocarditis)
- Yealy DM, et al. Dysrhythmias. In: Marx JA, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 6th ed. St. Louis, Mo.: Mosby; 2006. http://www.mdconsult.com/das/book/body/130129214-4/826148372/1365/221.html#4-u1.0-B0-323-02845-4..50083-4_3679. Accessed April 2, 2009.
- Arrhythmias. In: Libby P, et al, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Philadelphia, Pa.: Saunders Elsevier; 2007. http://www.mdconsult.com/book/player/book.do?method=display&type=bookPage&decorator=header&eid=4-u1.0-B978-1-4160-4106-1..50054-6--cesec188&displayedEid=4-u1.0-B978-1-4160-4106-1..50054-6--cesec196&uniq=130129214&isbn=978-1-4160-4106-1&sid=826147556. Accessed April 2, 2009.
- Podrid PJ. Clinical significance and treatment of ventricular premature beats. http://www.uptodate.com/home/index.html. Accessed April 2, 2009.
- Arrhythmia. National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/dci/Diseases/arr/arr_whatis.html. Accessed April 2, 2009.
- Martin DT. Arrhythmias. In: Noble J, et al. Noble: Textbook of Primary Care Medicine. 3rd ed. St. Louis, Mo.: Mosby; 2001. http://www.mdconsult.com/das/book/body/130129214-5/826149799/959/391.html#4-u1.0-B0-323-00828-3..50066-2_1733. Accessed April 2, 2009.
