[LEFT HIS BUNDLE BRANCH BLOCK ASSOCIATED WITH LEFT VENTRICULAR TORSION AND REDUCED EJECTION FRACTION].

The influence of left His bundle branch block (LBBB) on left ventricular (LV) torsion in patients with cardiomyopathy remains to be elucidated. The aim of this study was to evaluate LV torsion associated with LBBB and hemodynamic consequences of possible changes. We studied 64 patients with ischemic and dilatation cardiomyopathy (LV ejection fraction less than 40%) divided into 2 groups, with narrow and middle (153 ms) duration QRS complexes. Despite similar LV contractility, patients with LBBB had much less pronounced LV rotation and torsion. Torsion in patients with LBBB and narrow QRS complex was estimated at 2.95 ± 3.34 and 5.87 ± 3.83 respectively (p < 0.01). Moreover; the group of patients with LBBB contained much more subjects with abnormal unidirectional rotation of the basal and apical parts than the group with narrow QRS complex, namely 11 (50%) and 9 (21.9%) respectively (p < 0.001). Patients with LBBB and abnormal LV rotation sowed much longer delay of posterior wall contractility (63.3 ± 35.1 mc) compared with those having LBBB and multidirectional physiological LV rotation (8.0 ± 17/9 mc) (p < 0.001) which suggests a higher degree of mechanical desynchronization. T is concluded that LBBB has negative effect on LV electrical activation and contractility resulting in abnormal torsion and mechanical desynchronization.