[An echocardiographic study of patients with left bundle branch block]

24 patients (19 females and 5 males) between 45 and 81 years of age (average age 61.6) with chronic left bundle branch block and with no signs of reduced left ventricular function have been studied by M-Mode echocardiography. These patients have been split into three groups: A) pts. with normal indexes of left ventricular function and normal thickness of the left ventricular walls; B) pts. with normal indexes of left ventricular function and thickness of the interventricular septum at upper limits or increased; C) pts. with different cardiac pathologies but with no signs of reduced ventricular function. The contractility indexes and the motion of the interventricular septum in both the basal and the medial portion have been studied. The results did not show any important variation concerning the ventricular function compared to the normal values. The study of the septal motion pointed out, as a main feature of the left bundle branch block, a preejective posterior motion followed by: a) a normal posterior systolic motion of the interventricular septum, or b) a posterior systolic motion followed by a further posterior protodiastolic motion (delayed motion), or c) an anterior systolic and posterior diastolic motion (paradoxical motion). The alterations of the septal movement ranked in different degrees. The clearest alterations were peculiarly found in the patients of the first group. The patiens of the third group, besides, have shown the lightest alterations. The results allowed to deduce that patients with left bundle branch block can have both normal motion or alterations of the interventricular septum motion of different degree.(ABSTRACT TRUNCATED AT 250 WORDS)