Long-Term Predictors of Mortality and Malignant Ventricular Arrhythmias in Patients with Right Ventricular Outflow Tract Tachycardia

Background: Right ventricular outflow tract tachycardia(RVOT-T) could be the concealed form of arrhythmogenic right ventricular cardiomyopathy/dysplasia(ARVC/D). However, the outcome of RVOT-T is variable, and the predictors of mortality and malignant ventricular arrhythmia are undefined. The purpose of this study was to investigate the predictors of long-term outcome in patients with RVOT-T. Methods: The cohort included 122 patients with clinically-documented RVOT-T. Regarding the demographic, electrocardiographic, structural, and invasive electrophysiological characteristics, several factors were explored to predict the cause of mortality, malignant ventricular arrhythmia, and implantable cardioverter defibrillator (ICD) implantation. Results: A total of 25(20%) patients fulfilled the ARVD new Task Force (TF) criteria [TF(+)]. The mean follow-up duration was 48 ±39 months (range 3-120). Fifteen patients (12%) underwent ICD implantation [13 in TF(+)] for secondary prevention. All-cause mortality was noted in five patients [2 in TF(+)], and 8 had malignant ventricular arrhythmia [6 in TF(+)]. Malignant ventricular arrhythmia and mortality occurred in five TF(-) patients (4.1%). On multivariate analysis, independent predictors of events included hypertension (OR=6.32, P=0.043), left ventricular systolic dysfunction (OR=8.26, P=0.009). Conclusion: Without fulfilling the ARVC/D new TF criteria, patients with RVOT-T carried the risk of malignant ventricular arrhythmia and mortality. Hypertension and left ventricle systolic dysfunction (not the right ventricular dysfunction) are the predictors of long-term outcome in patients with RVOT-T.