Left Bundle Branch Block and Left Ventricular Hypertrophy: Electrocardiographic-Pathologic Correlations

¹ Intern, Medical Service, Harbor General Hospital, Torrance, California
² Assistant Professor of Medicine, University of Utah College of Medicine and Teaching Scholar of the American Heart Association. Staff Physician and Director, Coronary Intensive Care Unit, VA Hospital, Salt Lake City, Utah

A clinical-pathologic study was made of 50 patients with complete left bundle branch block who had postmortem examinations performed at three Salt Lake City hospitals. Forty (80 percent) were found to have left ventricular hypertrophy as determined from measured left ventricular wall thickness but only 14 had electrocardiographic evidence of this while two of the ten patients without left ventricular hypertrophy had positive electrocardiographic criteria. Twenty-six of 40 patients with anatomic left ventricular hypertrophy did not have electrocardiographic evidence of this. Forty-eight of 50 patients (96 percent) had heart weights greater than expected for body weight which probably reflected increased left ventricular mass. It is suggested that while left ventricular hypertrophy is very common in patients with left bundle branch block, its presence cannot be predictably obtained from the electrocardiogram with the criteria used.