Pseudo repetitive non-reentrant ventriculoatrial synchrony: Current challenges.

BACKGROUND: We recently described a novel pacemaker-mediated arrhythmia in Abbott cardiac implantable electronic devices (CIED), called pseudo-RNRVAS, that mimics repetitive non-reentrant ventriculoatrial synchrony (RNRVAS), but can appear in patients with ventriculoatrial (VA) block. It is caused by sinus-p-waves, trapped in the post-ventricular atrial refractory period (PVARP), which mimic VA conduction. The p-waves are followed by atrial pacing during the myocardial refractory time, which can trigger atrial fibrillation (AF). Pseudo-RNRVAS and RNRVAS are probably more common than appreciated, but the recognition and differentiation of the two can be challenging because most CIEDs do not recognize and store them. OBJECTIVE: We illustrate practical challenges in the assessment of Pseudo-RNRVAS and provide programming options that proved safe and effective for preventing Pseudo-RNRVAS and reducing the risk for typical RNRVAS. METHODS AND RESULTS: We illustrate in 10 patients the characteristics of Pseudo-RNRVAS and their treatment. The outcome regarding the recurrence of pseudo-RNRVAS after 6 months of follow-up was collected. Inappropriate atrial pacing during pseudo-RNRVAS resulted in AF in six patients. After shortening the PVARP in nine, inactivation/reduction of rate response in four, and reduction of the basic pacing rate in one patient, pseudo-RNRVAS was avoided in eight patients and reduced in one. In one patient AF became permanent. CONCLUSIONS: Pseudo-RNRVAS is a pacemaker-mediated arrhythmia that can appear in patients without VA conduction and may lead to AF. The suggested adjustments of pacing parameters were safe and effective in preventing the arrhythmia.

Novel Pacemaker-Mediated Arrhythmia Without Ventriculoatrial Conduction Can Induce Atrial Fibrillation.

Cardiovascular implantable electronic devices can initiate and sustain pacemaker-mediated arrhythmias. Endless loop tachycardia and repetitive non-re-entrant ventriculoatrial synchrony (RNRVAS) are well-described examples of pacemaker-mediated arrhythmias. However, such arrhythmias only occur in the presence of ventriculoatrial conduction. We identified a novel pacemaker-mediated arrhythmia that closely mimics RNRVAS but in the absence of ventriculoatrial conduction. We identified these arrhythmias in 9 patients, all with a St. Jude Medical/Abbott device, recorded as inappropriate mode-switch episodes by a device algorithm that includes paced events in the atrial counter. This report describes the mechanism, discusses clinical implications, and outlines programming options to eliminate this pseudo-RNRVAS.