Repetitive Non–Re-Entrant Ventriculoatrial Synchrony Causing Heart Failure Exacerbation

BACKGROUND: Repetitive non-reentrant ventriculoatrial synchrony (RNRVAS) is an under-recognized pacemaker-mediated rhythm that can cause atrioventricular (AV) dyssynchrony and heart failure symptoms. CASE SUMMARY: A 65-year-old man with advanced nonischemic cardiomyopathy and dual-chamber implantable cardioverter-defibrillator presented with worsening heart failure symptoms. A 12-lead electrocardiogram (ECG) demonstrated ventricular pacing with retrograde atrial conduction followed by atrial pacing with functional atrial noncapture, consistent with RNRVAS. Device interrogation confirmed frequent automatic mode switching episodes. Targeted device reprogramming, including lowering the lower rate limit and shortening the AV delay restored AV synchrony and resulted in clinical improvement. DISCUSSION: RNRVAS may evade standard device detection algorithms and present with subtle but clinically significant hemodynamic compromise. Careful ECG analysis can facilitate timely diagnosis and guide simple programming adjustments, with profound symptom improvement. TAKE-HOME MESSAGE: Careful analysis of surface ECGs can reveal RNRVAS and guide simple pacemaker reprogramming that restores AV synchrony and improves heart failure symptoms.