PMID: 6983805Jan 1, 1982Paper

Synchronized and desynchronized sinus node activity

Acta Cardiologica
L SzatmaryA Medvedowsky

Abstract

In certain cases because of sinus arrhythmia and/or anarchic return and postreturn cycles caused by premature atrial stimulation, the sinoatrial conduction time cannot be calculated since a chaotic postextrasystolic pattern appears. We examined 49 patients with a history and ECG signs suggesting sinus node dysfunction by programmed extrastimulation method as proposed by Strauss et al. prior to and after pharmacologic autonomic blockade (with propranolol 0.2 mg/kg body weight and atropine sulfate 0.04 mg/kg intravenously). Patients with normal intrinsic heart rate (IHR) (n = 31) showed chaotic postextrasystolic responses in 38%, which in every case could be eliminated by autonomic blockade, resulting in a clear I and II phase with a well estimated intrinsic conduction time. Patients with pathologic IHR (n = 18) gave chaotic responses in 22% which after drug testing increased up to 72%. The chaotic postextrasystolic patterns are to be interpreted as the desynchronization of the sinus potentials, while plateau (phase II) as functional integrity, synchronized activity of the sinus node, dependent on the momentaneous balance of the autonomous tone, and on the integrity of the pacemaker cells. The desynchronized chaotic responses are...Continue Reading

Related Concepts

Related Feeds

Atrial Fibrillation

Atrial fibrillation is a common arrhythmia that is associated with substantial morbidity and mortality, particularly due to stroke and thromboembolism. Here is the latest research.

Arrhythmia

Arrhythmias are abnormalities in heart rhythms, which can be either too fast or too slow. They can result from abnormalities of the initiation of an impulse or impulse conduction or a combination of both. Here is the latest research on arrhythmias.

Cardiac Conduction System

The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Discover the latest research on the cardiac conduction system here.

Addiction

This feed focuses mechanisms underlying addiction and addictive behaviour including heroin and opium dependence, alcohol intoxication, gambling, and tobacco addiction.