FREQUENCY AND CLINICAL OUTCOME IN CONDUCTION DEFECTS IN ACUTE MYOCARDIAL INFARCTION
AbstractBackground: Conduction defects complicating acute myocardial infarction (MI) are frequent andassociated with increased mortality and complications. Common conduction defects after acute MIare atrioventricular nodal blocks (1st, 2nd and 3rd degree) and intraventricular conduction defects(right or left bundle branch blocks and hemiblocks). In myocardial infarction occlusion ofcoronary arteries at different levels affects the conduction system of heart leading to various typesof blocks. Conduction defects usually reflect extensive damage to the myocardium. Methods: Inthis descriptive case series with non-probability purposive sampling, 345 cases of acute STelevation myocardial Infarction were studied at Armed Forces Institute of Cardiology/NationalInstitute of Heart Disease, Rawalpindi from May 2007 to May 2008. ECG was continuouslyobserved in CCU and daily ECGs were done. Conduction defects whether transient or persistentwere recorded in pre-designed proforma in addition to other clinical features and associatedcomplications during hospital stay. Results: Out of 345 patients, 251 (72.8%) patients receivedthrombolytic therapy and 61 (17.6%) developed various types of conduction defects (Group A)and 284 had no significant conduction defects (Group B). Isolated complete atrioventricular block(AVB) at the node level occurred in 28 patients (8.1%) mainly in inferior MI. Bundle branchesBlocks occurred in 32 (9.2%) patients mostly in Anterior MI. One patient (0.6%) had completeheart block at bundle branch level. All patients with complete atrioventricular block reverted tosinus rhythm except one who required permanent pacemaker. Mortality rate and clinicalcomplications were higher in group A as compared to group B. Conclusion: Conduction defectsare common even in this thrombolytic era. Patients with conduction defects are at high risk ofinhospital complications and mortality. They need close monitoring and optimum clinical care toreduce mortality and morbidity.Keywords: Conduction defects, Acute myocardial infarction, Bundle branch blocks
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