Transcatheter occlusion of the coronary sinus increases radiofrequency ablation lesion size in the left ventricular myocardium: a new approach to improve the efficiency of ventricular tachyarrhythmia substrate destruction

The aim. The results of ventricular tachyarrhythmia catheter ablation in patients with structural heart diseases remains to be improved. Both evolution of the arrhythmia substrate and its deep location are the main reasons for standard endocardial ablation limitations. Theoretically, the reduction of myocardial perfusion rate may improve convective heating of the myocardium during radiofrequency (RF) ablation, expanding the volume of damage. The purpose of this study was to assess the effect of coronary sinus (CS) occlusion in order to reduce myocardial perfusion during RF ablation on the volume of myocardial damage. Methods. The study was performed on 13 pigs. Following vascular access accomplishment, a balloon catheter was inserted into the lumen of the CS. A 3.5-mm open-irrigated RF ablation catheter was inserted into the cavity of the left ventricle. RF applications were applied in an alternate order, with and without CS occlusion (power 30 and 40W, application time 40 and 30 s, respectively). Each ablation point was marked on a three-dimensional electroanatomic map. After euthanasia, myocardial lesions were analyzed. Results. The analysis of 50 RF applications was performed (22 with CS occlusion and 28 without CS occlusion). At the same time, 28 applications (13 with occlusion and 15 without occlusion) were performed at a power of 40W, and 22 applications (9 with occlusion and 13 without occlusion) at a power of 30 watts. There was a trend toward the increase in lesion sizes created during CS occlusion. Significantly larger lesions were detected with 40W applications during CS occlusion when compared with open CS applications: depth 11.6±3.9 vs. 8.8±3.8 mm (p=0.04), diameter 11.7±4.6 vs. 8.5±3.9 mm (p=0.03), volume 504.2±499.5 vs. 183.0±157.5 mm 3 (p=0.01). Transmural myocardial lesions were more often encountered during applications with CS occlusion with both power settings, 30 and 40W: 68.2% of transmural lesions versus 39.3%; p=0.046. Conclusion. RF applications with a power of 40W and CS occlusion are characterized by greater depth, diameter, and volume of damage, as well as a greater frequency of transmural necrosis. Temporary transcatheter occlusion of CS can be proposed for ablation of ventricular arrhythmia with extended and deep substrate.