Atrial Overdrive Pacing: Is VA Linking Present?

Abstract

Atrial tachycardia, AV node reentry, entrainmentA 57-year-old patient presented with narrow-complex tachycardia (NCT) without discernable P waves on the ECG. He had previously undergone an aortic root and aortic valve replacement 6 years before. At electrophysiological studies, baseline measurements of AH and HV were 92 and 46 milliseconds, respectively. A stable and sustained NCT at the cycle length (CL) of 302 milliseconds was readily inducible. There was 1:1 atrioventricular relationship with a VA interval at the proximal coronary sinus (CS) of 160 milliseconds. Ventricular overdrive pacing (VOP) at a cycle length of 280 milliseconds resulted in VA block and failed to entrain the atrium. Atrial overdrive pacing (AOP) at 280 milliseconds was then performed at the high septal right atrium and coronary sinus ostium (Fig. 1A,B). Is VA linking demonstrated by this pacing maneuver? CommentaryVA block during VOP excludes AVRT and strongly favors AT, 1 but AVNRT with retrograde block in the lower common pathway 2 is a potential differential diagnosis. AOP to assess for VA linking by comparing the VA interval on the first return beat to the VA during tachycardia can be useful to differentiate AVNRT (presence of VA linking with difference <10 milliseconds) from atrial tachycardia (absence of VA linking).3 However, VA linking could exist coincidentally in AT, and repeating this maneuver at different AOP CLs and from different atrial sites has been proposed to increase its predictive value. 1In panel A, atrial activation at the CS during AOP precedes the pacing stimulus, which represents a very long intra-atrial conduction time from the high right atrial septum to the CS ostium, and suggests a macroreentrant atrial tachycardia mechanism. Measurement of the V-V intervals following AOP confirms that the last entrained ventricular beat should

The transition of the tachycardia from narrow to wide by a spontaneous atrial premature beat: What is the mechanism?

“…In the current case, even if His potential is not clear; there was a delay in the subsequent RB and QRS by 120 msec confirming engagement of slow AV nodal pathway 3 . There was also a fixed VA linking 4 . These responses exclude JT and AT, and leaves only AVNRT and the much less commonly observed NV/NFRT 5 .…”

Pseudo VA Linking With Atrial Overdrive Pacing

“…To the Editor I read with interest the recent case report by Leventopoulos et al 1 published in the Journal of Cardiovascular Electrophysiology. For the differential diagnosis, they performed atrial overdrive pacing (AOP) during macroreentrant atrial tachycardia (AT) with 1:1 AV relationship from the high right atrial septum (HRAS) and proximal coronary sinus (PCS).…”