2. Ectopic Beats
Published Online: 1 NOV 2012
Copyright © 2013 John Wiley & Sons, Ltd.
Bennett's Cardiac Arrhythmias: Practical Notes on Interpretation and Treatment, Eighth Edition
How to Cite
Bennett, D. H. (2012) Ectopic Beats, in Bennett's Cardiac Arrhythmias: Practical Notes on Interpretation and Treatment, Eighth Edition, John Wiley & Sons, Ltd, Oxford. doi: 10.1002/9781118432389.ch2
- Published Online: 1 NOV 2012
- Published Print: 14 JAN 2013
Print ISBN: 9780470674932
Online ISBN: 9781118432389
- Atrial ectopic beats;
- Atrioventricular junctional ectopic beats;
- Ectopic beats;
- Ventricular ectopic beats
The terms ectopic beat, extrasystole and premature contraction are, for practical purposes, synonymous. They refer to an impulse originating from the atria, atrioventricular (AV) junction or ventricles that arises prematurely in the cardiac cycle.
Usually the AV junction and bundle branches will conduct an atrial ectopic to the ventricles normally, resulting in a narrow QRS complex. The prematurity of an atrial ectopic beat is such that the P wave may be superimposed on the preceding T wave.
The impulse of a ventricular ectopic beat is not conducted through the ventricles via the rapidly conducting His–Purkinje system. The resultant complexes are therefore broad (> 0.12 s) and bizarre in shape, and will not be preceded by a premature P wave. Ventricular ectopic beats are often idiopathic but when caused by cardiac disease are associated with an increased cardiovascular mortality that will not be reduced by antiarrhythmic drugs.