Should we stay or should we go: assessment of the need for the implantation of a definite pacemaker in a population of acute coronary syndrome that evolved in advanced atrioventricular block

Abstract Introduction The incidence of advanced atrioventricular block (AVB) secondary to acute coronary syndrome (ACS) has been decreasing in the era of percutaneous revascularization and in most cases is transitory and does not require pacemaker (PM) implantation. Purpose Our aim was to assess the characteristics of patients with AVB as a consequence of the ACS and compare those with and without PM implantation, in what regards in-hospital and at 1 year outcomes. Methods We performed a retrospective analysis of all patients admitted with AVB secondary to ACS in Portugal between October of 2010 and August of 2021 with data from the Real World Portuguese Registry on Acute Coronary Syndromes (ProACS). Medical records were analysed for demographic, procedural data and outcomes. Results Sex hundred and seventy one (671) patients with AVB secondary to ACS were admitted, which corresponded to 2.2% of the total cohort. The mean age was 70±13 with a male preponderance (66%). The ACS was categorized as ST elevation Myocardial Infarction (STEMI) in 76.4%, non-STEMI (NSTEMI) in 22.1%, and unstable angina (UA) in 1.5%. Of the patients admitted with AVB, 8.6% implanted a permanent PM. The was no clinically relevant differences in both groups in what regards to medical priors or medication. Regarding the location of the infarction, an Anterior STEMI was the diagnosis of admission in 36.8% (vs 14.5%; OR 3.45, CI 95% 1.31–9.06, p<0.05) of patients that implanted a PM, and the left descending artery was more frequently the culprit artery, and an Inferior STEMI was the diagnosis of 63.2% (vs 83.7%; OR 0.31, CI 95% 0.12–0.82, p<0.05) of patients and a right coronary artery was more frequently the culprit artery. The presence of cardiovascular shock and in-hospital death was significantly more frequent in the group that did not implant a PM (OR 0.40; CI 95% 0.17–0.95, p<0.05 and OR 0.33; CI 0.12–0.92, p<0.05 respectively) and the implantation of PM was a negative predictor of in-hospital death (OR 0.28; CI 95% 0.08–0.93, p<0.05). The follow up at 1 year was performed in two hundred and sixty three (263) patients, 10.6% with an implanted PM. The survival analysis demonstrated increased mortality and a combined end-point of death and readmissions in the population of AVB that did not implant PM compared with a population who did not present with AVB (p<0.05) with the Kaplan Meier curves widening significantly (Figure 1). This difference was not observed compared with an AVB population that implanted PM. Conclusions In patients with AVB secondary to ACS, the implantation of a PM might have been withheld in more severe patients, accounting for the increased mortality observed, and this population has worse outcomes at 1 year, leaving open to the hypothesis if either due to a more severe clinical status or the recurrence of AVB. Funding Acknowledgement Type of funding sources: None.