The Significance of New Left Bundle Branch Block Complicating Acute Myocardial Infarction

The aim of our study was to evaluate the impact of new LBBB on left ventricular systolic function and arrhythmic risk in patients with acute myocardial infarction and unicoronarian lesion. We prospectively studied the patients with acute myocardial infarction with and without LBBB and unicoronarian lesion after a mean of 16.51 � 2.41 months from the onset of acute coronary event. We observed a higher risk of ventricular premature beats and left ventricular systolic disfunction in patients with left bundle branch block. Also, the presence of left bundle branch block (F = 3.64; p [ 0.005; partly h2= 0.33) and the duration of the QRS complex (F = 4.17; p [ 0.005; partly h2= 0.36) was statistically significantly correlated with the value of left ventricular ejection fraction. Almost a double number of patients with left bundle branch block had an ejection fraction below 30%, despite an early revascularization. Patients with acute myocardial infarction and left bundle branch block represent a relatively small group but with an increased risk of malignant ventricular arrhythmias and left ventricular systolic dysfunction, and they should therefore benefit from a promptly and appropriately treatment in order to improve long term outcome.