Sinoatrial arrest

Sinoatrial arrest or sinus arrest is a medical condition wherin the sinoatrial node of the heart transiently ceases to generate the electrical impulses that normally stimulate the myocardial tissues to contract and thus the heart to beat. Since the heart contains multiple pacemakers, this interruption of the cardiac cycle generally lasts only a few seconds before another part of the heart, such as the atrio-ventricular junction or the ventricles, begins pacing and restores the heart action. This condition can be detected on an electrocardiogram (EKG) as a brief period of irregular length with no electrical activity before either the sinoatrial node resumes normal pacing, or another pacemaker begins pacing. If a pacemaker other than the sinoatrial node is pacing the heart, this condition is known as an escape rhythm. If no other pacemaker begins pacing during an episode of sinus arrest it becomes a cardiac arrest. This condition is sometimes confused with sinoatrial block, a condition in which the pacing impulse is generated, but fails to conduct through the myocardium. Differential diagnosis of the two conditions is possible by examining the exact length of the interruption of cardiac activity.

References

*cite web |url=http://bmj.bmjjournals.com/cgi/content/full/324/7336/535 |title=ABC of clinical electrocardiography |accessdate=2008-04-28 |author=David Da Costa et al. |date=2002-03-02