Diagnosis of right ventricular overload by body surface QRST isointegral maps in children with postoperative right bundle branch block

Abstract The utility of body surface QRST isointegral maps (QRST-Imaps) for the detection of right ventricular (RV) overload was examined in children with postoperative development of right bundle branch block. In healthy children with no evidence of bundle branch block (n = 31), the QRST-Imap demonstrated a maximum at the left anterior chest and a minimum near the right shoulder with a single dipole distribution. The positive areas extended from the left anterior chest to the left back, and negative areas extended from the right anterior chest to the right back. Children with complete right bundle branch block but without heart disease demonstrated a QRST-Imap that was similar to that seen in normal children. In patients with RV overload (n = 15; 8 with ventricular septal defect and complicated anomaly and 7 with tetralogy of Fallot), the QRST-Imaps were abnormal and demonstrated double maxima, a rightward shift of the maximum, and extension of positive areas to the right chest. In the 10 patients who developed postoperative complete right bundle branch block, 4 had no evidence of RV overload by hemodynamic or echocardiographic assessment and demonstrated a normal QRST-Imap. In the six children who had residual RV overload during hemodynamic assessment, the QRST-Imap was abnormal. These results suggest that the QRST-Imap is a useful method for the detection of RV overload in pediatric patients complicated with conduction disturbances.