Local chemical ablation of myocardium via transvenous access: results of an experimental study

Background: Ventricular tachycardia, especially in patients with structural heart disease, is a life-threatening condition. Standard methods, such as radiofrequency ablation, are often ineffective against deep or epicardial arrhythmogenic foci, and transarterial chemical ablation with ethanol is insufficiently selective and risk- bearing for extensive myocardial damage. A retrograde transvenous approach for myocardial chemical ablation, exploiting the high permeability of coronary vein walls, is being considered as an alternative. Objective: The study was aimed to assess the efficacy and safety on formation of local myocardial chemical ablation using selective injection of an aliphatic VVF34 composition into an isolated coronary vein segment. Methods: The study was performed on minipigs (n = 4). The target segment of the coronary vein was isolated using a multi-balloon occlusion technique, followed by the injection of 1 ml of the VVF34 composition. Histological examinations of the myocardium were performed at 1 and 3 months after intervention to assess fibrosis formation. Results: The procedure was successfully completed in all animals without intra- or postoperative complications. Histological analysis confirmed the formation of sharply marginated fibrosis foci in the myocardium adjacent to the injection site. The active inflammatory reaction and initial fibrotic degeneration were revealed at 1 month after injection, and the formation of mature homogeneous areas of sclerosis without significant inflammatory infiltration was identified 3 months later. Conclusion: The transvenous chemical myocardial ablation with VVF34 composition using balloon isolation of venous segment has proven its efficacy and safety in the experiment. This approach enables to create controlled zones of fibrosis and is promising for highly selective targeting of deep and epicardial arrhythmogenic origins inaccessible to radiofrequency ablation, opening new possibilities for the treatment of resistant arrhythmias