Electrocardiographic diagnosis of left ventricular hypertrophy in the presence of complete right bundle branch block.

There are few data evaluating electrocardiographic diagnosis of left ventricular (LV) hypertrophy in the presence of right bundle branch block (BBB). This study assesses the relative value of multiple electrocardiographic variables for detecting LV hypertrophy in patients with right BBB. LV hypertrophy was defined as LV mass greater than or equal to 215 g calculated from the Penn method using standard M-mode echo measurements. Sixty-two patients were evaluated (ages 41 to 94) and 35 had LV hypertrophy. None of the electrocardiographic criteria was sensitive; the best was mean QRS axis less than or equal to -30 degrees (sensitivity) 52%) and excessive negative P terminal force (sensitivity 28%). Several electrocardiographic variables were specific: Sokolow index greater than or equal to 35 mm (100%), RV5 or RV6 greater than or equal to 25 mm (96.3%), RI + SIII greater than or equal to 25 mm (92.6%) and intrinsicoid deflection greater than or equal to 0.05 seconds (88.5%). Conventional electrocardiographic criteria do not reliably detect LV hypertrophy in the presence of right BBB, but several criteria are relatively specific for LV hypertrophy.