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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.