Background

Catheter ablation has emerged an important treatment modality for patients with recurrent ventricular tachycardia (VT). Recently, modern contact-force sensing catheters have become available enabling temperature-controlled radiofrequency ablation with higher power settings and shorter ablation duration. However, only sparse data is available on safety and efficacy of temperature-controlled radiofrequency ablation of VT.

Aims

To analyze feasibility, efficacy and safety of temperature-controlled ablation in patients undergoing VT ablation.

Methods

Consecutive patients undergoing endo- and epicardial catheter ablation for recurrent VT between 01/2020 and 01/2022 were prospectively enrolled. Ablation was conducted using a contact force sensing catheter allowing temperature-controlled ablation with a target temperature of 55°C and automatic adjustment of power to a maximum of 50 W (study group). Radiofrequency was delivered over 30 sec and contact forces of >10g were aimed for. Right and left ventricular high-density mapping was conducted in all patients. Programmed ventricular stimulation was performed for VT induction. Catheter ablation targeted induced VT and substrate modification of abnormal intracardiac electrograms. The primary procedural endpoint was non-inducibility of any sustained VT. Elimination of all abnormal electrograms was defined as the procedural endpoint of substrate modification. The study group was compared to patients undergoing VT ablation with a conventional power-controlled contact-force sensing catheter aiming at a power delivery of 40 W over 30 seconds (control group).

Results

Thirty-four patients were included into the study group and 69 patients into the control group. 32 patients (94.1%) of the study group were male and mean age was 63.3±12.9 years. ICM was present in 19 patients (59.4%), DCM in 11 patients (34.4%), arrhythmogenic right ventricular cardiomyopathy in 2 patients (6.2%) and mean left ventricular ejection fraction was 35.9±11.1% in the study group. Epicardial ablation was performed in 5 patients (14.7%). Baseline data of the two groups did not differ significantly. Procedure time in the study group was 2.2±0.8 hours with a fluoroscopy time of 7.8±4.5 min and an area dosage product of 1023.11±169.2 cGy*cm². Mapping time during sinus rhythm was 5.38±3.8 min for the right ventricle, 14.2±7.4 min for the left ventricle and 9.9±1.3 min for epicardial mapping. Mean ablation time was 39.3±19.6 min. Procedural data did not differ significantly between the two groups. VT was inducible in 28 patients (82.4%) in the study group and in 58 patients (84.1%) of the control group. Termination of VT by ablation was achieved in 92.9% of the patients in the study group and in 94.8% of the patients in the control group (p=0.39). Non-inducibility of any VT was achieved in 31 patients (91.2%) in the study group and in 65 patients (94.2%) of the control group (p=0.68).  No steam pops occurred and no severe periprocedural complications were observed in both groups. Two patients (2.9%) in the control group had groin hematoma with conservative management. During follow-up of 280.8±26.4 days VT recurred in 8 patients (25%) in the study group and 29 patients (42%) in the control group (p=0.07).

Conclusion

Temperature-controlled ablation of VT in patients with structural heart disease is comparable to conventional power-controlled ablation of VT regarding feasibility, acute procedural success and safety.