Relationship of Conduction Defects and In-Hospital Outcome after Acute ST Segment Elevation Myocardial Infarction

The presence of conduction defects complicating acute myocardial infarction (MI) is relatively frequent and is associated with increased short and long term mortality. Thrombolytic therapy has been established to reduce the mortality in acute MI, however its role in reducing the incidence of conduction defects is less clearly defined. Morbidity and mortality associated with conduction defects also remain unchanged. This study was aimed to assess the correlation between conduction defects and adverse in-hospital outcome of patients with acute ST segment elevation MI. This cross sectional descriptive type of observational study was conducted among 100 purposively selected patients with acute ST segment elevation MI in the coronary care unit (CCU) of Mymensingh Medical College Hospital, Bangladesh from June 2012 to March 2013. The patients were divided into two groups depending on the presence or absence of conduction defects namely Group A- 40 patients with conduction defects and Group B- 60 patients without conduction defects. Highest number of the patients (36.0%) was in the age group of 45-55 years. In case of inferior MI, age groups 45-55 years and 55-65 years had equal number of patients (30.4%). Only 2.0% patients were in age group of 75-85 years and this group had only inferior MI. Total number of female patients were 16(16.0%). Female patients had more inferior MI (17.4%) than anterior MI (15.9%). Number of MI patients was slightly more in inferior MI (46.0%) than anterior MI (44.0%). Group B had equal number of patients in both anterior and inferior MI. Conduction defects were more common in inferior MI (43.5%) than anterior MI (40.9%). Atrio-ventricular conduction defects were more common in inferior MI whereas intra-ventricular conduction defects were more common in anterior MI. Complete heart block (CHB) was more prevalent in inferior MI. Complications were more common in Group A (65.0%) than Group B (18.3%). In terms of complications the difference between two groups were significant (p<0.001). Group A showed higher rate of mortality (20.0%) than Group B (3.3%). In cases of anterior MI difference in mortality between Group A and Group B was highly significant (p<0.001). Conduction defects in the setting of acute MI are a common finding. Atrio-ventricular conduction defects occur more frequently in inferior MI whereas intra-ventricular conduction defects were more frequently encountered in anterior MI. Patients with conduction defects had more complications than those without conduction defects. Presence of conduction defects significantly increases the mortality of patients with anterior MI.