Systemic and coronary hemodynamic effects of transthoracic direct current shock

1435-1803

Springer Online Journal Archives 1860-2000

Medicine

Summary 1. This study in anesthetized mongrel dogs reports the acute systemic and coronary hemodynamic effects of direct current transthoracic shock similar to that used to change cardiac rhythm. 2. In control animals there was an impressive almost immediate increase in cardiac rate, output and work and an acute transient reduction in systemic, pulmonary and coronary vascular resistance which quickly returned toward normal. 3. The cardiovascular response is damped somewhat but still present after beta adrenergic blockade with propranolol or reserpine depletion of catecholamines. Thus catecholamine release is believed to be partially but not completely responsible for the changes seen. 4. The response is also reduced by vagotomy and by local anesthesia of the chest wall beneath the site of application of the paddles. The possibility is discussed that the response represents the complex reflex known as the “alarm” reaction. 5. The acute hemodynamic changes produced by transthoracic current discharge could be important in some of the infrequent complications of electrical conversion of cardiac arrhythmias. 6. A minor increase in coronary sinus blood temperature occurred with a 200 and 400 Watt second transthoracic discharge. It would seem likely that this should have been greater if a cardiac thermal burning were produced.

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