Successful radiofrequency ablation of adenosine-sensitive right ventricular outflow tract tachycardia.

We report on a patient without evidence of structural heart disease who presented with adenosine-sensitive sustained ventricular tachycardia with left bundle branch block and right axis QRS morphology. Endocardial catheter mapping revealed the origin of ventricular tachycardia to be located in the right ventricular outflow tract, where the earliest endocardial activation during ventricular tachycardia was registered 30-40 ms prior to onset of QRS complex in the surface ECG. Pace-mapping provided no additional information; we found a good match between 12 lead surface ECGs registered during spontaneous episodes of ventricular tachycardia and those recorded during pacing in a relatively large area in the right ventricular outflow tract. The 10th application of radiofrequency current abolished ventricular tachycardia temporarily, but it recurred within 30 min. After the 28th radiofrequency current delivery ventricular tachycardia was permanently abolished.