(935) Heart Rate Comparison of Oral P2Y12 Inhibitors in Inferior ST Elevation Myocardial Infarctions

Introduction: Half of patients suffering an inferior ST elevation myocardial infarction (STEMI) have complications associated with increased mortality, including development of bradycardia and atrioventricular (AV) block. Current guidelines recommend aspirin and an oral P2Y12 inhibitor as dual antiplatelet therapy (DAPT) to prevent stent thrombosis in those who undergo percutaneous coronary intervention (PCI) with stent placement. Ticagrelor has been shown to increase adenosine plasma concentrations leading to adverse effects including bradyarrhythmias. Clopidogrel and prasugrel have not shown any association with bradyarrhythmias. The purpose of this study was to determine the incidence of bradycardia after ticagrelor initiation compared to clopidogrel/prasugrel in inferior STEMI patients.

Methods: This was a retrospective, multicenter study conducted at three primary PCI centers between January 1, 2017 and September 30, 2022. Adult patients were included if they were diagnosed with an inferior STEMI to the right coronary artery and treated with PCI followed by an oral P2Y12 inhibitor. The primary outcome was heart rate (HR) at 48 hours or discharge, whichever first, after administration of ticagrelor compared to clopidogrel/prasugrel. Secondary outcomes included incidence of bradycardic events, timing to initiation of beta-blocker, and beta-blocker therapy initiation or continuation at discharge.

Results: This study enrolled 331 patients, 172 in the ticagrelor group and 159 in the clopidogrel/prasugrel group. There was no statistical difference between groups with regards to the primary outcome, with a median HR of 76 bpm [67-85] in the ticagrelor group vs 73 bpm [66-84] in the clopidogrel/prasugrel group (p=0.24). No differences were observed between groups regarding any secondary outcomes.

Conclusions: No difference was demonstrated between ticagrelor and clopidogrel or prasugrel in heart rate, bradycardic events, or ability to tolerate beta-blocker therapy after initiation of a P2Y12 inhibitor in patients with an inferior STEMI.