Prolonged Transient Atrial Electrical Silence Following Termination of Chronic Atrial Tachyarrhythmias

Abstract

The present report expands the spectrum of the syndrome of atrial standstill and raises interesting questions regarding possible electrophysiologic mechanism(s) of prolonged post overdrive atrial standstill. The report suggests that chronic overdrive of sinus and subsidiary atrial pacemakers may result in calcium overloading of cardiac cells, which is known to cause suppression of pacemaker activity as well as increased intracellular resistance. These mechanisms can possibly result in either prolonged suppression of sinus and atrial pacemaker activity and/or pacemaker exit block.

Sinus Node Dysfunction in Atrial Fibrillation: Cause or Effect?

“…20 Turitto reported a series of patients that demonstrated atrial standstill for up to 12 hours following ablation of long-standing AFL and AF. 21 These findings suggest functional depression of sino-atrial activity. In 2/3 patients, depression was permanent and a pacemaker was needed.…”

Association of atrial fibrillation and atrial flutter with sick sinus syndrome: a review of the issue based on examples of clinical observations

“…There are studies demonstra ting that paroxysmal AF can lead to inhibition of SN function which leads to prolonged sinus pauses after the end of AF paroxysm [38]. Many authors consider prolonged sinus pauses on termination AF as predictors to pacemaker implantation in AF patients after RFA [21,35,37,45]. There were only divergences in the length of the pauses.…”

Prolonged Asystole after Termination of Atrial Arrhythmias:

“…In this issue of PACE, Turitto and colleagues 1 call attention to the problem of prolonged transient electrical silence following termination of longstanding atrial tachyarrhythmias. On literally the same morning that the paper arrived in my editor's box, our own group was discussing two patients with similar problems who had arrived at our hospital in the previous 24 hours (Fig.…”

“…Turitto 1 and others 5 speculate that changes in ionic channels, including calcium‐loading of the sinus node cells, may be a factor in the post‐termination asystole. Some, based on canine studies, have postulated tachycardia‐induced changes in autonomic tone 6 …”

“…Two of the cases in the Turitto report had atrial flutter and one of these remained in persistent sinus rhythm following ablation. The time course for reestablishment of sinus rhythm is typically less than 24 hours, 1,2 so that a decision for or against implantation of a permanent pacemaker can be made expeditiously.…”