Voltage criteria of left ventricular hypertrophy in sudden and nonsudden coronary artery disease mortality: the Italian section of the Seven Countries Study. It is unclear whether sudden or nonsudden death can be predicted independently from other risk factors for coronary artery disease (CAD). Therefore, this investigation was undertaken to measure 12-lead QRS voltage sum, a recently proposed (Am J Cardiol 1985;55:485-494) index of left ventricular (LV) hypertrophy, and its ability to predict either subsequent sudden (less than 2 hours) or nonsudden CAD death during 20 to 23 years of follow-up in 1,588 middle aged men (40 to 61 years old) from 2 cohorts of the Italian section of the Seven Countries Study who were free of demonstrable CAD (at entry examination in 1962). The Sokolow-Lyon and the modified Sokolow-Lyon indexes, 2 standard electrocardiographic methods to detect LV hypertrophy were also measured and compared. During follow-up, 67 patients died suddenly and 87 died a nonsudden CAD death. In the Cox proportional-hazards model, age, mean blood pressure, heart rate, body mass index, cholesterol, physical activity, smoking habit, ST-T alterations (Minnesota codes 4.1 to 4.3 together with 5.1 to 5.3) and the 3 electrocardiographic indexes, all measured at the time of enrollment into the study, were included. The 12-lead QRS voltage sum retained significant and independent relation to sudden death (t = 2.00); Sokolow-Lyon index entered the Cox solution for nonsudden CAD death but the association was inverse (t = -2.10). ST-T alterations were significantly associated only with nonsudden CAD death (t = 2.19). Thus, in addition to several known risk factors, measurement of 12-lead QRS voltage sum in middle-aged men without clinical evidence of heart disease may help identify subjects at an increased risk of sudden death; nonsudden CAD death is predicted by Sokolow-Lyon index and by ST-T alterations. The usefulness of these indexes needs to be tested in different populations. 