Radiofrequency catheter ablation is a first line therapy for many supraventricular and some ventricular tachycardias due to a high success rate and a low probability of complications. Although the majority of them are related to the catheterization technique, some are due to a direct effect of radiofrequency application. We report a patient with a nonsustained, repetitive, monomorphic ventricular arrhythmia that presented, after a successful radiofrequency ablation, an incessant sustained monomorphic ventricular tachycardia requiring a new ablation procedure.