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

Background: Ventricular tachycardia (VT) originating in the right vent ricle may be seen in the absence of structural heart disease. Although this is thought to be associated with a benign course, it may cause i ntolerable symptoms and be difficult to control with antiarrhythmic dr ugs. Aims: To assess the value of radiofrequency ablation of right ven tricular tachycardia and to characterise the clinical and electrophysi ologic features predictive of successful ablation. Methods: Nine patie nts (aged 20-49 years) with clinical VT underwent cardiac mapping whic h localised the site of origin of VT in the right ventricle. At least three separate areas of VT origin were identified in these patients. A blation of VT was defined as suppression of VT at the time of hospital discharge. Results: Five patients had successful ablation of the tach ycardia focus with long term suppression of the arrhythmia. Patients w ith successful ablation were characterised by inability to induce VT w ith 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 with out structural heart disease is a heterogeneous disorder with varied c linical and electrophysiologic features. Successful ablation of VT may be predicted by consideration of these variables.