Cardiac memory (t-wave memory) after ablation of posteroseptal accessory pathway.

BACKGROUND

Cardiac memory is a phenomenon characterized by transient T-wave abnormalities occurring during normal sinus rhythm, after a period of altered ventricular depolarization, where the T-wave vector has the same direction as the vector of the previously altered QRS complex (T-wave inversion). It is a form of electrical remodelling of the ventricular, where the T-wave follows ("remembers") a previously altered QRS vector.

METHODS AND RESULTS

Over a 5-year period (2002-2006), 525 consecutive patients underwent electrophysiological study. One hundred and one patients underwent ablation of the atrioventricular reentry tachycardia (AVRT) with an accessory pathway (AP). Forty-two of them were without delta wave on the electrocardiogram (concealed accessory pathway), and 58 patients had an open form of accessory pathways, with delta wave on EKG (Wolff-Parkinson-White syndrome) and only one patient had an accessory pathway between the right atrium and right bundle branch (Mahaim form). According to the location of the accessory pathway, 17 patients (29.3 %) had an accessory pathway in the right posteroseptal region. There was the highest percentage of the appearance of inversion of the T-wave in patients with this position of accessory pathway. T-wave changes were followed in the frontal plane (leads II, III, and aVF). Electrocardiogram (ECG) signs of cardiac memory were present in 16 of 17 (94.1 %) patients within one day after the ablation. The post-ablation T-wave vector had the same direction as the vector of the pre-excited QRS complex (and delta wave) creating inferior T-wave inversions. There was no correlation between the number or duration of energy applications and the extent of cardiac memory post ablation. A majority (90% of cases) of ECGs recorded 3 months after the procedure showed complete or almost complete normalization. None of the patients with T-wave inversion after ablation had a recurrence of preexcitation or tachycardia during the follow-up period of 12 +/- 4 months.

CONCLUSIONS

T-wave inversion in leads II, III and aVF with the disappearance of the delta wave after ablation of the accessory pathway in patients with Wolff-Parkinson-White syndrome (accessory pathway in the right posteroseptal region of the heart), is the most powerful marker of successful ablation.