Study of Conduction Blocks in ST Elevation Myocardial Infarction – A Cross-Sectional Analysis

Abstract

Conduction blocks complicating ST(ST-segment)-elevation myocardial infarction are associated with increased morbidity and mortality. Research indicates that anterior and inferior wall myocardial infarction were the most encountered causes of blocks but with conflicting results. However, patterns of conduction blocks have not been widely established in our population. The aim was to study the various patterns of conduction blocks following ST-elevation myocardial infarction and their prognostic implications. Prospectively, 70 patients, aged > 18 years, diagnosed with ST segment elevation myocardial infarction were included in the study. Post intensive care unit admission, all patients were observed for conduction blocks using a standard 12-lead electrocardiogram and repeated the same every 48 h throughout the hospitalization stay. Statistical analysis was performed using software R version 3.6.0. Out of 70 patients, 70% were males. Mean age was 60.7 ± 13.4 years. The proportion of blocks was first-degree heart block (28.6%), Mobitz II heart block (20%), complete heart block (17.1%), Mobitz I heart block (11.4%), right bundle branch block (10%), left bundle branch block (10%), left anterior hemiblock (1.4%), and trifascicular block (1.4%). No significant diference was found between males and females with respect to various conduction heart blocks (P > .05). Mortality was observed only in patients with complete heart block (11.4%) and first-degree heart block (2.8%; P = .003). Statistically, no significant diference was observed between various conduction blocks with respect to cardiac enzymes, random blood sugar, and lipid levels (P > .05). High mortality rate has been found in the patients with complete heart block indicating that severity of conduction block is a predictor of poor outcome in the ST-elevation myocardial infarction patients.