Vectorcardiographic diagnosis of left ventricular hypertrophy.

The vectorcardiographic diagnosis of left ventricular hypertrophy, using the Frank lead system, was evaluated in 93 autopsied male patients (70 with hypertrophy of the left ventricle and 23 without such hypertrophy). The criterion of the maximal QRS magnitude in the transverse plane greater than 2.2 mv below the age of 50 years and 1.8 mv at the age of 50 or more was positive in 61% of hypertrophied hearts and negative for all the nonhypertrophied hearts. The criterion of the T loop vector greater than Ho700 in the transverse plane was positive in 82% of 49 hypertrophied hearts and positive in one (7%) of 15 normal hearts for which the T loop was available. The maximal QRS magnitudes in the frontal and sagittal planes had too low a sensitivity to be of value while the angles of the maximal QRS vector in the transverse and sagittal planes was too nonspecific to be useful. By combining the QRS magnitude and the T loop vector in the transverse plane, the diagnosis of left ventricular hypertrophy was made in 90% of 49 hypertrophied hearts for which the T loop was available.