A Rare Case of RNRVAS Termination and Re-Initiation Visualized on a 12-Lead ECG

Sep 29, 2026

A 76-year-old woman with sick sinus syndrome received a dual-chamber pacemaker and was followed routinely. During a visit, a 12-lead ECG demonstrated abrupt cessation and re-initiation of ventricular pacing, consistent with repetitive non-reentrant ventriculoatrial synchrony (RNRVAS). Detailed ECG sequence showed VP followed by retrograde atrial activation and atrial non-capture during the atrial refractory period, repeating in a diagnostic loop. Ventriculoatrial conduction timings and device algorithms (VIP and PVC response) explained how RNRVAS persisted until intrinsic ventricular activity and then terminated with VIP OFF.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages4

Reading Time10 min

AccessFree to download

Case description and patient background

Pacemaker settings and follow-up

ECG findings and diagnostic sequence

RNRVAS loop on 12-lead ECG

Ventriculoatrial conduction and PMT initiation

Algorithm-based termination mechanisms

VIP ON/OFF behavior

PVC response timing and refractory periods

Journal of Arrhythmia A Rare Case ofRNRVAS Termination and Re-Initiation Visualized on a 12-Lead ECG Tomoyoshi Morioku1 | Yasuyuki Egami2 | Yasuharu Matsunaga-Lee2 | Masamichi Yano2 | Masami Nishino2 1Clinical Engineering Technologist, Osaka Rosai Hospital, Osaka, Japan | 2Division of Cardiology, Osaka Rosai Hospital, Osaka, Japan Correspondence: Yasuyuki Egami ([egmyasuyuki@gmail.com](egmyasuyuki@gmail.com)) Received: 9 September 2025 | Revised: 21 December 2025 | Accepted: 28 December 2025 Keywords: 12-lead electrocardiogram | PVC response | repetitive non-reentrant ventriculoatrial synchrony | ventricular intrinsic preference The diagnosis of pacemaker malfunction typically relies on telemetry interrogation. However, careful analysis of a 12-lead electrocardiogram (ECG), combined with knowledge of pacemaker algorithms, enables accurate diagnosis without interrogation. A 76-year-old woman with sick sinus syndrome underwent dual-chamber pacemaker implantation (Zephyr XL DR 5826, Abbott) six years earlier for symptomatic bradycardia. The pacemaker was programmed in DDD mode with the following settings: lower rate, 70 bpm; maximum tracking rate, 105 bpm; atrioventricular delay (AVD): paced/sensed, 250/225 ms; postventricular atrial refractory period (PVARP), 275 ms; postventricular atrial blanking (PVAB), 150 ms; ventricular intrinsic preference (VIP), ON with a 200-ms AVD extension to encourage intrinsic conduction; and PVC response, ON. She remained asymptomatic and continued follow-up. During a routine visit, a 12-lead ECG was recorded at rest (Figure 1) . The ECG (25 mm/s, 10 mm/mV) revealed abrupt cessation andre-initiation of ventricular pacing (VP), demonstrating repetitive non-reentrant ventriculoatrial synchrony (RNRVAS), a rare pacemaker-mediated arrhythmia (Figure 1B) . VP stimulus (①) was followed by a retrograde atrial activation (② red circle), and the subsequent atrial pacing (AP) (③) occurred during the atrial refractory period, resulting in non-capture. This sequence (VP → retrograde P wave → non-capture of AP) repeated ina loop, fulfilling the diagnostic criteria for RNRVAS [1] . Theventriculoatrial (VA) conduction time (for both premature ventricular contraction [PVC] and VP) measured on the 12-lead ECG was 160 ms. VA conduction was confirmed on the intracardiac electrogram during a pacemaker-mediated tachycardia (PMT) event, where VP was followed by atrial sensing (AS) . The VA conduction time was approximately 340 ms, exceeding the PVARP (275 ms) and resulting in AS recognition and PMT initiation (Figure 2) . RNRVAS persisted until the first intrinsic ventricular beat, then terminated with VIP OFF. The VIP algorithm promotes intrinsic conduction by extending the AVD and switches between ON and OFF every 30 s with three cycles. VIP turns OFF when VP occurs for three consecutive beats during the extended AVD and turns ON when three consecutive VS events are detected either during the extended AVD or within the normal AVD. In this case, the sequence of VIP OFF and ON was as follows (Figure 3): ① Three consecutive VP events occurred during extended AVD of 450 ms. ② VIP turned OFF, and the AVD returned to its baseline value of 250 ms. ③ The VA interval was extended to 607 ms (857–250 = 607) . ④ In the previous beat, when VIP was active, the VA interval was 407 ms (857–450 = 407) . ⑤ This extended VA interval (③) allowed the AP stimulus to capture the atrium (highlighted in yellow) beyond the physiologic refractory period caused by the preceding retrograde conduction, resulting in RNRVAS termination. Thus, the transition from VIP ON to OFF status restored the baseline AVD, prolonged the VA interval, and interrupted the RNRVAS loop. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2026 The Author(s). Journal of Arrhythmia publish

FAQs

How was pacemaker malfunction evaluated in this case?

The authors used careful 12-lead ECG analysis combined with understanding of pacemaker algorithms, rather than relying solely on telemetry interrogation.

What ECG sequence established the diagnosis of RNRVAS?

Ventricular pacing was followed by a retrograde atrial activation, and the subsequent atrial pacing occurred during the atrial refractory period, causing non-capture; this VP → retrograde P wave → non-captured AP loop repeated.

What role did the VIP algorithm play in terminating RNRVAS?

RNRVAS persisted until the first intrinsic ventricular beat, and termination occurred when the VIP status transitioned (VIP OFF and then ON behavior), restoring baseline AVD and prolonging the VA interval to interrupt the repetitive loop.

Sep 29, 2026

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