IDIOPATHIC RIGHT-VENTRICULAR TACHYCARDIA - ELECTROPHYSIOLOGY AND RESPONSE TO CATHETER ABLATION

Background: Ventricular tachycardia (VT) originating in the right ventricle may be seen in the absence of structural heart disease. Although this is thought to be associated with a benign course, it may cause intolerable symptoms and be difficult to control with antiarrhythmic drugs. Aims: To assess the value of radiofrequency ablation of right ventricular tachycardia and to characterise the clinical and electrophysiologic features predictive of successful ablation. Methods: Nine patients (aged 20-49 years) with clinical VT underwent cardiac mapping which localised the site of origin of VT in the right ventricle. At least three separate areas of VT origin were identified in these patients. Ablation of VT was defined as suppression of VT at the time of hospital discharge. Results: Five patients had successful ablation of the tachycardia focus with long term suppression of the arrhythmia. Patients with successful ablation were characterised by inability to induce VT with extrastimuli, a distinct VT morphology with a rS pattern in lead 1, right axis deviation, facilitation of VT with isoprenaline and site of origin in the lateral outflow tract. During VT, an earlier site of presystolic activation was found in successful patients compared with unsuccessful ablations. Right ventricular tachycardia in patients without structural heart disease is a heterogeneous disorder with varied clinical and electrophysiologic features. Successful ablation of VT may be predicted by consideration of these variables.