Left ventricular hypertrophy in left bundle branch block.

The detection of left ventricular hypertrophy (LVH) in the presence of left bundle branch block (LBBB) remains a difficult clinical problem. Its prevalence and significance have not previously been studied in a group of living patients. M-mode echocardiography was utilized to determine the prevalence of anatomic LVH in 28 patients with LBBB. Various ECG and chest x-ray criteria as predictors of LVH were assessed. Anatomic LVH was present in 89% by echocardiography. A left atrial abnormality on ECG and a cardio-thoracic ratio greater than .50 were the best predictors of LVH. Hypertension and/or ischemic heart disease was present in 78.5% of the patients while only one patient was free of any evidence of cardiovascular disease.