Correlations between radiologic heart size and orthogonal electrocardiograms in patients with left ventricular overload

Abstract

Correlations between radiologic heart size and electrocardiographic measurements of the QRS complex were performed in 100 patients with clinical evidence of left ventricular overload (LVO). Frank's corrected orthogonal lead system was used. ECG analysis was performed by digital computation. Radiologic heart size correlated best with: (1) spatial magnitude of the time integral of QRS (SÂQRS); (2) the sum of R wave magnitudes in leads X and Z; (3) rightward displacement of point J; (4) time interval between the onset of QRS and the peak of the R wave in lead X. Combinations of either one of the first two criteria with the third or fourth were found to be best for the recognition of cardiac enlargement in patients with left ventricular overload. When the number of false-positive cases was reduced to zero, the maximal recognition rate, based solely on QRS criteria, was 76 per cent. A narrow and/or figure-of-eight QRS loop configuration in the horizontal plane projection was found frequently in cases with cardiac enlargement. This finding may serve as a clue for predicting left ventricular enlargement.