IN-HOSPITAL MORTALITY IN PATIENTS OF ST ELEVATION MI PRESENTING WITH RIGHT BUNDLE BRANCH BLOCK

Abstract

Objective: To determine the frequency of in-hospital mortality of patients havingST elevation MI with right bundle branch block (RBBB) after giving emergencytreatment, within 72-hours of hospital admission.

Methodology: This observational cross-sectional study was conducted fromFebruary to August 2012 in casualty and medical wards at National Institute ofCardiovascular Diseases Karachi. All consecutive patients with ST elevation MI(STEMI) having right bundle branch block were included. In hospital mortality ofevery patient was assessed during 72-hrs of in-hospital admission. Dataregarding age, gender, co-morbidities, type of ST elevation MI, type of emergencytreatment and in-hospital mortality were documented. Frequencies andpercentages of categorical variables, mean and standard deviation of continuousvariables were calculated using SPSS version 17.

Results: Out of 120 patients 80.8% were males . Of all the patients 38.3% werediabetic, 35% were hypertensive, 33.3% were smokers and 25.0% were thosewho had no co morbidities. Acute anterior wall MI was found in 87.5%, inferiorwall MI in 6.7% and acute lateral wall MI was found in 3.3% patients while in 2.5%patients both anterior wall and lateral wall MI was found. The mean age of thepatients was 56.59±9.92 years. The mean duration of diabetes andhypertension was 13.72±6.49 years and 17.12±.6.96 years respectively.About 75% patients received streptokinase, and 25% were treated with primaryPCI. The overall mortality rate was 28(23.3%) patients mostly males 23(82.1%).Mortality was high in 61-70 years age group 16(57.1%) while no mortality wasobserved in age groups < 40 years. Mortality rate was high in smokers15(53.6%). Mortality in acute anterior wall myocardial infarction was 27(96.4%)and 01(3.6%) with anteriolateral wall MI. Mortality rate was very high in patientstreated with streptokinase 23(82.1%) as compared to primary PCI (p <0.05).

Conclusion: In STEMI, RBBB was an independent predictor of high in-hospitalmortality. Patients who have RBBB accompanying anterior AMI at presentation orwho develop new BBB early after fibrinolytic therapy independently have highermortality than patients without these conduction abnormalities.