Further evidence supporting the concept of T-wave memory: observation in patients having undergone high-energy direct current catheter ablation of the Wolff-Parkinson-White syndrome.

Following successful high-energy direct current catheter ablation of posterior septal accessory pathways, serial T-wave changes were observed in seven patients with Wolff-Parkinson-White syndrome, but not in two patients with a concealed accessory bypass pathway. Following catheter ablation in the patients with Wolff-Parkinson-White syndrome, the previously upright T-waves in the inferior electrocardiographic leads became inferiorly directed. Serial electrocardiograms following catheter ablation revealed slow regression of these T-wave changes over time. In contrast, in the two patients in whom a concealed accessory pathway was present, the T-waves prior to and following the procedure were upright. In these two patients, serial electrocardiograms showed no evolution of the T-wave vector over the same time period. Although a small rise in myocardial CK enzymes was observed, ischaemic injury in the area of catheter ablation could not be documented by post-procedure echocardiography, tomographic thallium scintigraphy, technetium pyrophosphate scintigraphy or coronary angiography with left ventriculography. We conclude that the observed T-wave changes in the patients with Wolff-Parkinson-White syndrome may be a result of the change in depolarization sequence resulting from loss of pre-excitation, and that the time-dependent nature of these T-wave changes is consistent with the concept of T-wave 'memory'.