1Universitätsklinikum Münster Klinik für Kardiologie II - Rhythmologie Münster, Deutschland
Background: In about 8% of people who survived sudden cardiac death no structural or electrical heart disease can be identified. Some of these patients with idiopathic ventricular fibrillation (IVF) present ECG markers of early repolarization (Early Repolarization Syndrome). The Tpeak to Tend interval (TpTe) has been linked to increased arrhythmic risk in different clinical settings especially Brugada syndrome and Hypertrophic cardiomyopathie. As there is limited data about medium and long- term outcome of IVF, the aim of our single-center study was to observe sustained ventricular arrhythmia (VA) recurrences in these patients and to identify a possible correlation of VA with TpTe.
Methods and results: In this study, we retrospectively investigated 56 consecutive IVF patients (64.3% male; mean age 37.6 years) who received an implantable cardioverter-defibrillator (53.8% subcutaneous ICD (S-ICD)) for secondary prevention. Markers of early repolarization (QRS notching or slurring) were present in 32.1% of cases. During a mean follow-up of 41.2 months, 11 patients (19.6%) received in total 18 adequate ICD-therapies. VF was most the common cause for ICD-therapy (61.1%) but monomorphic or polymorphic VT also occurred in four, respectively one patient. Patients with VA recurrence showed longer TpTe compared to arrhythmia-free patients (105 ms vs. 91 ms, p=0.02). Especially patients with a prolonged TpTe (> 100 ms) and ERP had a 4.95-fold risk of recurrent VA (p=0.01).
Conclusion: Prolonged TpTe was associated with elevated VA recurrence in patients with survived IVF. This correlation was even more pronounced in the subgroup of patients with early repolarization pattern. Therefore TpTe might play a future role in risk stratification of patients with suspected early repolarization syndrome.