Introduction The aim of this study was to investigate the results of radiofrequency catheter ablation of ventricular tachycardia (VT) in patients with organic heart diseases utilising CARTO system and a saline-irrigated tip catheter.
Method 31 patients (26 men), aged from 6 to 75 years, had palpitation and sustained VT or ventricular fibrillation (VF) and 15 patients had the histories of syncope. 9 patients with Fallot syndromes after cardiac surgery, 4 patients with old myocardial infarction (one had ventricular electrical storm after ICD implantation), 1 patient with ventricular electrical storm after acute myocardial infarction, 17 patients with ARVC or dilated cardiomyopathy. CARTO system was used for directing mapping and ablating VT. For mappable VT, the VT mapping techniques included activation, entrainment, and voltage mapping using standard criteria. For unmappable VT, the site of origin was approximated by the site of pace mapping that generated QRS complexes similar to those of VT. Radiofrequency ablation was performed as linear lesions based on the location of the best pace map, the location of valvular anatomic boundaries, and the substrate defined by the voltage mapping.
Result 56 morphologies of VT (1–5 morphologies of VT in 1 patient) were induced in 29 patients, including 38 morphologies of mappable VT and 18 unmappable VT. In 24 patients who had at least 1 morphology of mappable VT, mapping and ablation was performed during VT, and in the other 5 patients who had unmappable VT, substrate mapping and ablation was performed during sinus rhythm. Radiofrequency ablation eliminated VT in 20 patients and failed to ablate VT in 9 patients (most had cardiomyopathy). In 1 ARVC patient with multiple morphologies of frequent ventricular premature beats (VPBs) and syncope, ablation of VPBs and VT substrate were performed. In the other patient who had drug-refractory ventricular electrical storm after acute myocardial infarction, ablation of VPBs originating from Purkinje network eliminated VT and VF recurrence. During 3 to 42 months of follow-up, 20 out of 22 patients who had a successful VT or VPBs ablation did not had VT and VF recurrence, and the 2 patient who had VT recurrence had a successful VT ablation in the second procedures. In the 9 patients who had a failure ablation of VT (no ICD implantation because of economic reason), antiarrhythmic drugs were taken. There were no VT recurrence in 2 patients and less VT attacks in 4 patients.
Conclusion Based on the electronanatomic mapping, radiofrequency ablation of VT using a saline-irrigated tip catheter in patients with organic heart diseases might have high successful and effective rate.