Safety and efficacy of intra-coronary chilled saline infusion during epicardial ablation in the left ventricular summit

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: The left ventricular (LV) summit is the most common epicardial site of idiopathic premature ventricular complexes (PVC) and is frequently associated with PVC-induced cardiomyopathy. Catheter ablation in the LV summit can be challenging due to its proximity with the major coronaries. Hypothesis: Infusion of chilled saline (5-10 degree Celsius) into the left main coronary artery cools the endothelium during epicardial ablation in the LV summit and therefore, protects the coronaries from thermal damage. PURPOSE: To determine the safety and efficacy of intra-coronary chilled saline infusion during epicardial ablation in the LV summit. METHODS: Patients with symptomatic idiopathic PVC from the LV summit formed the study population. Those with significant coronary artery disease (coronary stenosis >50%) or with a scar on cardiac MRI were excluded from the study. Irrigated ablation was performed in the epicardium either percutaneously or transvenously via the distal great cardiac vein (GCV). A coronary angiogram (CAG) was always performed before RF ablation (RFA) to delineate the distance of the ablation catheter from the proximal coronaries. Chilled saline (5-10 degree Celsius) was administered into the left main coronary artery (LMCA) via Judkins catheter at a constant rate of 50 ml/min throughout the entire duration of ablation. Post-RFA, CAG was repeated to exclude any damage to the coronary arteries. RESULTS: Between January 2020 and July 2022, 37 patients (mean age 47.2±11.6 years; 16 females) underwent epicardial ablation in the LV summit accompanied by intra-coronary chilled saline infusion. The mean LV ejection fraction was 46.6±7.9%, and 15 patients had LVEF <50% (PVC-induced cardiomyopathy). Epicardial ablation was performed percutaneously in six patients, whereas in 21 patients, it was done transvenously in the distal GCV. Chilled saline was infused into the LMCA during the entire duration of RFA without any untoward effect in any of the patients. Acute procedural success (complete elimination of the clinical PVC) was achieved in 34 out of the 37 patients. At a mean follow-up of 17±7.9 months, 35 patients (91.8%) were asymptomatic and free from the clinical arrhythmia. CONCLUSION: Intra-coronary chilled saline administered during epicardial ablation in the LV summit is safe and effective in preventing RF-induced thermal injury to the proximal coronary arteries.