Incidence and predictors of pacemaker implantation at follow-up after reversible high-degree sinus node dysfunction or atrioventricular block

Background: A pacemaker implantation is not indicated in cases of reversible high-degree symptomatic sinus node dysfunction (SND) and atrioventricular block (AVB). However, it remains uncertain whether these reversible automaticity/conduction disorders may recur in some patients at follow-up, in the absence of reversible cause. This retrospective study aimed to determine the incidence and predictive factors of permanent pacemaker (PPM) implantation at follow-up and after reversible high-degree SND/AVB.

Methods: Based on medical electronic files codes, we identified patients who were hospitalized in our cardiac intensive care unit between January 2003 and December 2020 due to reversible high-degree SND/AVB and who were discharged from the hospital alive and without PPM implantation. Acute myocardial infarction and post-cardiac surgery patients were excluded. We categorized the patients according to the need for PPM at follow-up due to non-reversible high-degree SND/AVB.

Results: Of the 93 patients included, 26 patients (28%) were readmitted for PPM implantation at follow-up after hospital discharge. Among baseline characteristics, compared with patients who did not have high-degree SND/AVB recurrence, those who had subsequent PPM implantation had less frequent previous hypertension (70% vs. 46%, p = .031). Regarding the initial causes of reversible SND/AVB, isolated hyperkalemia was found more often in the patients readmitted for PPM (19% vs. 3% vs. p = .017). Moreover, recurrence of high-degree SND/AVB was significantly associated with the presence of intraventricular conduction disorders (either bundle branch block or left bundle branch hemiblock) on ECG at discharge (36% in patients without PPM vs. 68% in PPM patients, p = .012).

Conclusion: Almost one third of the patients discharged alive from the hospital after a reversible high-degree SND/AVB needed a pacemaker implantation at follow-up. Complete bundle branch block or left bundle branch hemiblock on discharge ECG after recovery of atrioventricular conduction and/or sinus automaticity was associated with a greater risk of recurrence leading to pacemaker implantation.