Microvolt T-wave alternans is related to ventricular tachycardia in adults with repaired tetralogy of fallot

Authors:
O. Goktekin1, Z. Kucukdurmaz2, S. Babu-Narayan2, T. Wong2, M.G. Kaya2, M.A. Vatankulu2, Y.Y. Lam2, P. Kilner2, R. Sutton2, M.A. Gatzoulis2, 1Osmangasi University, Faculty of Medicine - Eskisehir - Turkey, 2Royal Bromton Hospital - London - United Kingdom,

Topic(s):
GUCH and paediatric cardiology others

Citation:
European Heart Journal ( 2007 ) 28 ( Abstract Supplement ), 151-152

Purpose: Microvolt T-wave alternans (MTWA) is a novel non-invasive method to identify patients at increased risk of cardiac arrest and sudden cardiac death from ventricular arrhythmias in ischemic heart disease and cardiomyopathies. Ventricular arrhythmia and sudden death are leading causes of morbidity and mortality late after repair of tetralogy of Fallot. We hypothesised that MTWA may related to the ventricular tachycardia (VT).

Method: Fifty-five patients with repaired ToF and freepulmonary regurgitation and 11 patients with ToF and documented VT were included study. Microvolt TWA was measured during submaximal treadmill exercise in all patients. Eight patients were excluded from the study because of poor electrocardiogram recordings with noise or frequent ectopic beats (n=4) and indeterminate result (n=4). As a result 58 patients (36 male, mean age, 35.3±12.2)including 9 patients with history of VT were evaluated for further analysis.

Results: MTWA was positive in 18 patients (31%) and negative in 40 patients (69%). Patients with VT were older than those without VT (45.14±13.4 versus 33.9±11.5 years, p=0.02). Age at first intervention (7.7±4.2 versus 4.4±5.3 years, p=0.2), age of repair (7±3.7 versus 5.7±5.6 years, p=0.1) or follow-up duration (34.5±2.7 years 28.2±8.2 versus p=0.09) were not significantly different between patients with and without VT. The sensitivity, specificity and negative predictive value of MTWA for VT were 66.6%, 75.5% and 92.5%, respectively. Patients with VT had more positive MTWA results than the ones without VT (6/9 (66%) versus 12/49 (24%) p=0.01). Patients with positive MTWA test had 6.1 times risk for having ventricular tachycardia (odds ratio 6.1, 95% CI 1.3 to 28.2). No significant relationship was found between presence of VT, maximal V alt and onset heart rate in patients with positive TWA (7.4±2.8 versus 6.7±2.1 mV, p=0.6 and 104.4±6.1 versus 102.5±5.7 bpm, p=0.5, respectively)Conclusion: MTWA was relatively common and relate to a history of documented VT in adult patients with repaired tetralogy of Fallot. Therefore MTWA may emerge as a useful non-invasive tool to identify Fallot patients at risk for malignant arrhythmia. Further prospective studies are needed to evaluate the prognostic value of this test.