Analysis of T wave changes by activation recovery interval in patients with atrial septal defect.

We examined the distributions of the activation recovery interval (ARI), which is correlated with the local action potential duration (APD), to clarify the origin of the repolarization changes in ASD. The ECGs, QRST isointegral maps and ARI isochronal maps of 21 children with ASD from 3 to 5 years old in age were studied in comparison with 21 age-matched normal children. A conventional and 87 unipolar body surface ECG were simultaneously recorded.

Non-dipolarity of heart potentials estimated by magnetocardiography in normal subjects.

We studied non-dipolarity characteristics during ventricular excitation in normal adults and children by magnetocardiography (MCG) by recording magnetic field on the thorax. The source and currents of the electrical dipole from the onset up to 60 ms of ventricular excitation were analyzed in 16 adults and 5 children. A single equivalent current dipole (ECD) was estimated by Sarvas' formula for the sphere model at 1 ms intervals.

Precordial leads QRST time integrals for evaluation of right ventricular overload in children with congenital heart diseases.

It was previously shown that body surface QRST isointegral maps of the anterior chest were abnormal in patients with right ventricular overload and that the abnormalities varied with hemodynamic status. The QRST isointegral maps were first characterized by using a departure index map for normal controls. The study group consisted of 14 patients with pulmonary stenosis (PS), 20 with tetralogy of Fallot, (TOF) and 43 with atrial septal defect (ASD).

QRST isointegral map reflects the sudden reduction of right ventricular pressure after balloon pulmonary valvuloplasty.

To elucidate the mechanism of electrocardiographic changes due to right ventricular pressure overload, serial changes on body surface maps recorded in two children with valvular pulmonary stenosis before and after successful reduction of right ventricular pressure by balloon valvuloplasty (BVP) were studied. Body surface maps and 12-lead electrocardiograms were simultaneously recorded before and 1-1.5 hours, 8 hours, and 5 days after BVP.

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

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.