AbstractThe electrocardiograms (ECG) of 64 subjects who exhibited an echocardiographically demonstrable increase in thickness of the interventricular septum and left ventricular posterior wall (Group 1,22 patients), isolated left ventricular internal dimension (Group 2, 26 patients), combined wall thickness and chamber diameter (Group 3, 2 patients), and septal thickness, (Group 4, asymmetric septal hypertrophy, 14 patients) were reviewed in order to determine sensitivity of ECG criteria for the diagnosis of left ventricular hypertrophy (LVH) proposed in 1949 by Sokolow and Lyon (13), in 1968 by Romhilt and Estes (14), and in 1973 the New York Heart Association (15). Relative sensitivity of the three methods was as follows: Total group, NYHA (77%)>Sokolow and Lyon (67%)>Romhilt and Estes (58%); Group 1, NYHA (91%)>Sokolow and Lyon (73%)>Romhilt and Estes (54%); Group 2, NYHA and Sokolow and Lyon (65%)>Romhilt and Estes (61%); Group 4, NYHA (79%)>Sokolow and Lyon (64%)>Romhilt and Estes (57%). We conclude that (1) ECG criteria of the NYHA for the diagnosis of LVH correlate best with an increase of ultrasonically determined septal, left ventricular posterior wall or left ventricular internal dimensions when compared with voltage criteria of Sokolow and Lyon and the point score system of Romhilt and Estes; and (2) isolated increase of left ventricular internal dimension, in the absence of thickened septum or posterior left ventricular wall, frequently results in ECG criteria compatible with the diagnosis of LVH.