Background: QRS duration has previously shown association with mortality in patients with acute myocardial infarction treated with thrombolytics, less is known in patients with suspected ST segment elevation myocardial infarction (STEMI) when assessing QRS duration on prehospital ECG. Thus, the objective was to investigate the prognostic effect of QRS duration on prehospital ECG and presence of classic left and right bundle branch block (LBBB/RBBB) for all-cause mortality in patients with suspected STEMI.
Method: In total 2105 consecutive patients (mean age 64±13years, 72% men) with suspected STEMI were prospectively included. QRS duration was registered from automated QRS measurement on prehospital ECG and patients were divided according to quartiles of QRS duration (<89ms, 89-98ms, 99-111ms and >111ms). Primary endpoint was all-cause 30-day mortality. Predictors of all-cause mortality were assessed using Cox proportional hazards analysis.
Results: Among all patients median QRS duration was 98ms (IQR 88-112ms). RBBB-morphology was seen in 126 patients (6.0%) and LBBB in 88 patients (4.2%), 80% were treated with percutaneous coronary intervention and the final diagnosis was STEMI in 1777 patients (84%). Thirty-day mortality was 7.6% in patients with suspected STEMI. In multivariable analysis, QRS duration>111ms (hazard ratio (HR) 3.08; 95% confidence interval (CI): 1.71-5.57, p=0.0002), LBBB - morphology (HR 3.0; 95% CI: 1.38-6.53, p=0.006) and RBBB (HR 3.68; 95% CI: 1.95-6.95, p<0.0001) were associated with 30 day all-cause mortality.
Conclusion: In patients with suspected STEMI, QRS prolongation, LBBB, and RBBB on prehospital ECG are associated with increased risk of death.
Copyright © 2017 Elsevier B.V. All rights reserved.