Sinoatrial arrest

Sinoatrial arrest (also known as sinus arrest or sinus pause) is a medical condition wherein 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. It is defined as lasting from 2.0 seconds to several minutes.^[1] 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 (ECG) 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. If the next available pacemaker takes over, it is in the following order:

1. Atrial escape (rate 60–80): originates within atria, not sinus node (normal P morphology is lost).

2. Junctional escape (rate 40–60): originates near the AV node; a normal P wave is not seen, may occasionally see a retrograde P wave.

3. Ventricular escape (rate 20–40): originates in ventricular conduction system; no P wave, wide, abnormal QRS.

Treatment includes stop medications that suppress the sinus node (beta blocker, Calcium channel blocker, digitalis); may need pacing.

References

↑ http://www.uptodate.com/contents/sinoatrial-nodal-pause-arrest-and-exit-block

David Da Costa; et al. (2002-03-02). "ABC of clinical electrocardiography". Retrieved 2008-04-28.

Cardiovascular disease (heart) (I00–I52, 390–429)

Ischaemic

Coronary disease	Coronary artery disease (CAD) Coronary artery aneurysm Spontaneous coronary artery dissection (SCAD) Coronary thrombosis Coronary vasospasm Myocardial bridge

Active ischemia	Angina pectoris Prinzmetal's angina Stable angina Acute coronary syndrome Myocardial infarction Unstable angina

Sequelae	hours Hibernating myocardium Myocardial stunning days Myocardial rupture weeks Aneurysm of heart / Ventricular aneurysm Dressler syndrome

Layers

Pericardium

Myocardium

Endocardium /
valves

Endocarditis	infective endocarditis Subacute bacterial endocarditis non-infective endocarditis Libman–Sacks endocarditis Nonbacterial thrombotic endocarditis

Valves	mitral regurgitation prolapse stenosis aortic stenosis insufficiency tricuspid stenosis insufficiency pulmonary stenosis insufficiency

Conduction /
arrhythmia

Bradycardia

Tachycardia
(paroxysmal and sinus)

Supraventricular	Atrial Multifocal Junctional AV nodal reentrant Junctional ectopic

Ventricular	Accelerated idioventricular rhythm Catecholaminergic polymorphic Torsades de pointes

Premature contraction

Pre-excitation syndrome

Flutter / fibrillation

Other / ungrouped

Other

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