QRS loop areas in selective right ventricular overload: relation to hemodynamic status.

The utility of vectorcardiographic relative QRS loop area criteria in identifying significant hemodynamic abnormality (a mean pulmonary artery pressure greater than 25 mmHg and/or a pulmonary to systemic flow ratio greater than 1.5) in patients with cardiac lesions associated with selective right ventricular overload was investigated in a consecutive series of patients, 291 with Heart Disease and 135 Controls. The specificity and predictive value of individual abnormally increased right quadrant areas were greater than 90% and greater than 80%, respectively. The predictive value of an isolated increase in left anterior area greater than 70% in identifying the absence of significant hemodynamic abnormality (= 91%) was similar to a negative VCG (= 80%). False positive increases in right quadrant areas were found only in association with counterclockwise transverse plane QRS loop rotation. The predictive value of a counterclockwise loop rose from 77% to 86% by increasing the diagnostic requirement for an abnormal increase in right inferior and posterior area from 20%, respectively, to 26%, respectively.