Evaluation of fragmented potentials in right bundle branch block without structural myocardium abnormalities. Study made by signal-averaged electrocardiogram on time and frequency domain

To evaluate if the presence of right bundle branch block (RBBB), without structural myocardial abnormalities (SMA) can generate fragmented potentials (FP) and spectral turbulence on signal-averaged electrocardiogram (SAECG). Twelve children with atrial septal defect (ASD) and incomplete right bundle branch block (IRBBB without SMA (group I) were compared to 17 children with post-operative tetralogy of Fallot (TF) with CRBBB, all with SMA, 5 with ventricular premature beats and 2 with sustained ventricular tachycardia (group II). All had SAECG on time (TD) and frequency domain (FD) with 5 variables analysed. All patients of group I had normal variables, in contrast with group II which presented abnormal variables suggesting FP and ST. In ASD without SMA, the isolated IRBBB did not generate FP and ST.