bradycardia

views updated May 18 2018

bradycardia describes a heart beat which is either habitually slow, or which drops from its usual rate. In health, bradycardia may be the result of athletic training, which reduces the resting heart rate. Persons with heart block have persistent or intermittent bradycardia. Sudden bradycardia can result in a dramatic fall in cardiac output and hence in arterial blood pressure, depriving the brain of blood flow and causing a ‘black-out’. Fainting (‘syncope’) is one such instance, caused by depression of the heart's pacemaker by the parasympathetic (vagus) nerves; acute exacerbation of heart block is another. From the Greek for ‘slow’ and ‘heart’.

Stuart Judge


See heart block; syncope; fainting.
The Oxford Companion to the Body COLIN BLAKEMORE and SHELIA JENNETT

bradycardia

views updated May 21 2018

brad·y·car·di·a / ˌbradiˈkärdēə/ • n. Med. abnormally slow heart action.

The Oxford Pocket Dictionary of Current English

bradycardia

views updated May 14 2018

bradycardia A decrease in heart rate. See tachycardia.

A Dictionary of Biology

bradycardia

views updated Jun 08 2018

bradycardia An unusually slow heartbeat, less than 60 beats/min. Such a low rate may be normal in trained athletes.

A Dictionary of Food and Nutrition DAVID A. BENDER

bradycardia

views updated May 21 2018

bradycardia (brad-i-kar-diă) n. slowing of the heart rate to less than 50 beats per minute.

A Dictionary of Nursing

bradycardia

views updated May 17 2018

bradycardia A condition in which the heart rate is reduced substantially.

A Dictionary of Ecology MICHAEL ALLABY

bradycardia

views updated Jun 11 2018

bradycardia A condition in which the heart rate is reduced substantially.

A Dictionary of Zoology MICHAEL ALLABY

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Bradycardia

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