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Epicardial ablation with cooled tip catheter close to the coronary arteries is effective and safe in the porcine heart if the ventricular potential is being monitored in the epicardium and endocardium.

BACKGROUND
Transthoracic epicardial ablation can be an alternative to conventional treatment for critical pathways of ventricular tachycardia located in the epicardium. However, the usefulness and safety of epicardial ablation close to the coronary arteries (CA) is not clear. The purpose of the present experimental animal study was to analyze the efficacy and safety of epicardial radiofrequency (RF) ablation close to the CA.


METHODS AND RESULTS
Of the left ventricle-epicardium ablated sites, 35 lesions (20 with cooling and 15 without cooling) were close to the CA (left anterior descending artery < or = 15 mm) and 33 lesions (23 with cooling and 10 without cooling) were further from the CA. For sites close to the CA, epicardial ablation was effective in 77% (15/20) with cooling and in 40% (6/15) without cooling. There was a significant difference of effective ablation between with cooling and without cooling (p < 0.05). For cooling, epicardial lesion size could be predicted by the change of endocardial ventricular potential using a basket catheter. No damage to major epicardial arteries was detected when the catheter tip was positioned 5 mm away from the CA.


CONCLUSIONS
Close to the CA, RF ablation with cooling is more effective than RF without cooling and is safe if the ablation sites are located 5 mm away from the major CA.