A Descriptive Study: - 2D - Echocardiography and Coronary Angiography Changes of RBBB in Acute Myocardial Infarction

Introduction: The new European Society of Cardiology guideline for ST- segment elevation myocardial infarction recommends that left and right bundle branch block should be considered equal for recommending urgent angiography in patients with suspected myocardial infarction. Aim: To investigate 2D Echocardiography and angiographic changes in anatomy and severity of coronary lesions in patients with and without right bundle branch block (RBBB) in the setting of anterior myocardial infarction (MI). Methods: Patients who admitted to Cardiac Care Unit with the diagnosis of acute anterior MI between Jan 2018 and Feb 2021 were retrospectively searched from our database. Out of 826 patients, 27 had RBBB (RBBB group) either at admission or in the course of anterior MI.35 thirty five patients who developed no intraventricular conduction defect during the course of anterior MI with selected as the control group. Results: Out of 27 patients, 20 had RBBB on admission and 7 developed RBBB in the course of acute MI. Left anterior descending artery (LAD) proximal lesion was more commonly detected in the RBBB group [16 (59.2%) vs.5 (25%) patients, p=0.003]. Left ventricular ejection fraction was lower (33.0?4.2% vs 36.7?4.9%, p=0.003) and end - systolic volume was higher (84.1?24.9 ml vs 74.6?22.0 ml, p=0.012) in patients with RBBB. Number of patients with high NYHA Killip grade (III and IV) was more in the RBBB group and number of patients with Killip grade I was more in the control group. Besides mean Killip class was higher in the RBBB group (1.65?0.90 vs 1.25?0.67, p=0.03). Two patients (7.4%) in the RBBB group and one patients (5.0%) in the control group diedduring hospitalization (p=0.67). Conclusion: Left ventricular ejection fraction decreases and Killip grade increases in case of RBBB in the setting of acute anterior MI. Culprit lesion in patients with RBBB is more commonly a LAD proximal lesion and threatened myocardial tissue is larger in patients with RBBB.