Transcoronary guidewire ablation with radiofrequency in a porcine animal model.

Objectives: Transcoronary ablation of septal hypertrophy (TASH) and surgical myectomy are the recommended treatment options for patients with hypertrophic obstructive cardiomyopathy refractory (HOCM) when conventional drug treatment is not sufficient. We describe the application of radiofrequency (RF) energy via coronary guidewires in an animal model for selective occlusion of coronary side branches that mimics the principle of TASH.

Methods: Transcoronary guidewire ablation of coronary vessels was performed in 5 adult pigs under general anaesthesia in an animal cathlab after successful bench testing of the ablation settings. After assessing transcoronary pacing parameters, RF energy was delivered via coronary guidewires insulated by coating or by a monorail balloon and positioned in different coronary side branches. Occlusion or patency of the specific coronary side branch was documented by coronary angiography after RF delivery.

Results: After the transcoronary RF ablation, the intended occlusion of the coronary vessel (thrombolysis in myocardial infarction [TIMI]-0 or TIMI-1 flow) could be verified by angiography in 82% of the septal branches attempted and 79% of the epicardial branches. The mean ablation duration was 10.3 seconds at 20-W power with an initial impedance of 176 ± 31 Ώ. No unintended occlusion of the main vessels occurred in any case.

Conclusions: RF ablation via coronary guidewires is a feasible method for inducing an acute occlusion of coronary vessels and may change the interventional therapy of HOCM if the current limitations of this technique are overcome.