Triage of Stable Patients With Suspected Acute Myocardial Infarction and Left Bundle Branch Block: A Multicenter, Propensity Score-Matched Analysis.

Abstract

A pragmatic immediate invasive strategy is recommended in patients with ischemic symptoms and suspected left bundle branch block acute myocardial infarction (LBBB-AMI). It is important to identify patients with LBBB-AMI who do not need to be treated with the same strategy as those with ST-segment elevation myocardial infarction (STEMI). In this study, we aimed to compare the outcome of stable but symptomatic patients with suspected LBBB-AMI with that of matched STEMI patients. All consecutive patients who were referred for percu - taneous coronary intervention (PCI) in a metropolitan, multicenter STEMI network in Germany were analyzed and stratified according to their ECG findings (STEMI or LBBB). Propensity score matching (PSM) and adjusted analyses were performed. 4563 patients were included: 4219 (92.5%) with STEMI, and 344 (7.5%) with LBBB-AMI. After the identification of stable patients and PSM (n = 187 LBBB-AMI, n = 557 STEMI), the odds ratios for LBBB-AMI patients were 1.61 (95% confidence interval, [0.78; 3.32]) for in-hospital mortality, 0.56 [0.32; 0.91] for culprit lesion, and 2.18 [1.24; 3.84] for impaired patency of infarct-related artery after PCI. The median peak creatine kinase level was 1075 U/L in the STEMI patients and 478 U/L in the LBBB-AMI patients (estimated difference: -153 U/L [-504; 196]). Approximately, 70% of the LBBB-AMI patients had a culprit lesion in combination with myocardial necrosis implying acute stenosis. Approximately, seven of ten symptomatic LBBB-AMI patients had acute culprit lesions requiring timely PCI. The findings support routine emergency coronary angiography in these patients. Future prospective trials should address more selective triage.