Use of a saline-irrigated tip catheter for ablation of ventricular tachycardia resistant to conventional radiofrequency ablation: Early experience

Irrigated Tip Catheter for Ablation of Resistant VT, Introduction: Radiofre quency (RF) catheter ablation of ventricular tachycardia (VT) may fail if t he critical isthmus is located intramyocardially or epicardially, The desig n of a saline-irrigated tip (SIT) catheter (Thermo-Cool(TM), Cordis-Webster ) involves active cooling of the tip electrode, which allows creation of la rger ablation lesions. Methods and Results: Eight patients (6 men, age 59 +/- 12 years) in whom th e clinical target VT (cycle length 430 +/- 97 msec) could not be ablated us ing a conventional 4-mm tip RF ablation catheter underwent additional attem pts to ablate this VT using a SIT catheter, Six patients had an old myocard ial infarction, 1 patient had a dilated cardiomyopathy, and 1 patient had a structurally normal heart. Ablation of the clinical target VT using a SIT catheter was attempted from the left ventricle in 6 (septal, posterobasal, and inferior: 2 each) and from the right ventricle in 2 patients (both sept al), by entrainment (n = 6), activation (n = 1), or pace mapping (n = 1), A mean of 6 +/- 5 (range 2 to 15) pulses were delivered. Target VT ablation was successful in 5 patients (63 %). After successful ablation, at a mean f ollow-up of 6.5 +/- 4 months and while taking antiarrhythmic drugs, all 5 p atients were free of VT recurrences. Conclusion: The clinical target VT could be ablated using a SIT catheter in 5 (63;%) of the 8 patients in whom ablation using a conventional RF cathet er was unsuccessful. In the 2 patients with septal VT, a biventricular appr oach to mapping and ablation was required.