Comparison of total 12-lead QRS voltage in a variety of cardiac conditions and its usefulness in predicting increased cardiac mass.

Echocardiography provides a more accurate method to determine increased cardiac mass than does electrocardiography. Nevertheless, most offices of physicians do not possess echocardiographic machines, but many possess electrocardiographic machines. Many electrocardiographic criteria have been used to determine increased cardiac mass, but few of the criteria have been measured against cardiac weight determined at necropsy or after cardiac transplantation. Such was the purpose of the present study. Cardiac weight at necropsy or after transplantation was determined in 359 patients with 11 different cardiac conditions, and total 12-lead electrocardiographic QRS voltage (from the peak of the R wave to the nadir of either the Q or the S wave, whichever was deeper) was measured in each patient. Even in hearts with massively increased cardiac mass (>1,000 g), the total 12-lead QRS voltage was clearly increased (>175 mm) in only 94%, but this criterion was superior to that of previously described electrocardiographic criteria for "left ventricular hypertrophy." Hearts with excessive adipose tissue infrequently had increased total 12-lead QRS voltage despite increased cardiac weight. Likewise, patients with fatal cardiac amyloidosis had hearts of increased weight but quite low total 12-lead QRS voltage. In conclusion, 12-lead QRS voltage is useful in predicting increased cardiac mass, but that predictability is dependent in part on the cause of the increased cardiac mass.