G011 Incidence and prognosis of ventricular tachycardia in apparently normal subjects

The prognosis of ventricular tachycardia (VT) is related to the presence of heart disease (HD). VT in patients without HD is considered as benign. However some sudden deaths were reported. The development of new methods as cardiac MRI has permitted to detect HD in some patients. The purpose of the study was to evaluate the incidence and prognosis of patients recruited since 30 years for VT and without apparent HD with conventional methods. Population 806 patients were admitted for sustained VT between 1978 and 2008. Methods: The following studies were performed: recording of ECG, signal averaged ECG, Holter monitoring, exercise testing (when possible), echocardiography, right angiography in patients with right VT, coronary angiography in patients older than 40 years and electrophysiological study. Results 74 patients (9 %), aged from 11 to 75 years (mean 46±18), 45 men, 29 women had normal echocardiogram and hemodynamic study. Right ventricular outflow tract (RVOT) VT was noted in 42 patients, verapamil-sensitive VT in 23; VT's were right and left in 3 patients, related to a bundle branch reentry in 1, of undetermined origin in 4 patients. VT developed at exercise testing in 15 patients and was inducible or occurred with isoproterenol in 54 patients (73 %). Erroneous diagnosis of supraventricular tachycardia with aberrancy was initially made in 5 patients. Beta blockers and/or antiarrhythmic drugs were initially prescribed. Defibrillator was implanted in one patient with syncopal RVOT-VT and 2 for a false diagnosis of right ventricle dysplasia made in 2002 at beginning of MRI. Catheter ablation for recurrent VT was performed in 3 patients with failure in one and in 1 patient for its job. Three patients were lost of view during follow-up (mean 11.5±6.6 years); remaining patients, but one are alive without recurrent VT and without drugs in half of them; 1 patient died from non cardiac cause. One patient developed dilated cardiomyopathy; 2 had permanent atrial fibrillation. Conclusions VT in patients without apparent HD after conventional studies (echocardiography, hemodynamic study) represented 9 % of VT and required rarely a non medical treatment.