216-74: Tpeak-Tend interval dispersion as a marker of ventricular fibrillation inducibility after therapeutic hypothermia in subjects with aborted arrhythmic sudden cardiac death

Background: Prolonged Tpeak-Tend interval and Tpeak-end/QT ratio have been shown to be markers of arrhythmogenesis in various cardiac disorders. But its dynamicity is one of obstacles to predict fatal ventricular arrhythmia.

Objective: The present study investigated whether Tpeak-Tend is associated with ventricular fibrillation inducibility after therapeutic hypothermia in subjects with aborted arrhythmic sudden cardiac death.

Methods: The study group included 31 patients (24 males, age 39.1 +/- 17.6 years) presenting with arrhythmic sudden cardiac death (9 idiopathic VFs, 13 J-wave syndromes, 6 long QT syndromes, 6 others) in whom Tpeak-Tend, Tpeak-Tend/QT, J wave amplitude were measured in ECG of the earliest medical contact and during therapeutic hypothermia; these patients underwent programmed ventricular stimulation.

Results: Sustained VF was induced in 9 patients (29%). Patients with inducible VF showed a large Tpeak-Tend interval dispersion in the first ECG (94.0 +/- 55.6 vs. 68.8 +/- 24.7 ms, P = 0.044) and a marked increase of the dispersion during the therapeutic hypothermia (36.2 +/- 51.2 vs. -6.1 +/- 45.5 ms, P = 0.039) compared with those without arrhythmias. The summation of J wave amplitude and QTc increased during therapeutic hypothermia. However, it was not associated with VF inducibility.

Conclusion: The Tpeak-Tend interval dispersion and the augmentation of the dispersion during therapeutic hypothermia are associated with VF inducibility in aborted arrhythmic sudden cardiac death. But prognostic value needs to be evaluated with ICD interrogation in further studies.