Effects of combined radiofrequency and direct current energy catheter ablation on ventricular myocardium in pigs

When radiofrequency catheter ablation of ventricular arrhythmiasis unsuccessful, an option may be to combine it with directcurrent energy. We therefore investigated the effects of sucha combination. Radiofrequency energy was delivered in a bipolar or unipolarfashion to the left and right ventricles through an ablationcatheter with a tip electrode 2 mm long, using a temperature-guidedradiofrequency generator. Radiofrequency ablation was followedby a single cathodal direct current shock (66 J) with the ablationcatheter positioned similarly in six closed-chest pigs. In acontrol group (six animals) only direct current ablation wasperformed, with one or two energy applications (66 J) in eachventricle. Two of six animals in the radiofrequency I direct current groupdied due to perforation in the follow-up period, 1 and 3.5 hafter the direct current ablation, respectively. Gross pathologicalexamination of the hearts revealed transmural lesions in allanimals. In the radiofrequency I direct current group four lesionswere perforated, three of which were located in the left ventricle.There was a significant increase in the number of perforationsin the radiofrequency/direct current group compared to the controlgroup, where perforation was never observed Haemorrhagic pericardialfluid was found in five of the six animals in the radiofrequency/directcurrent group compared to none in the control group. These findings show that myocardial ablation with radiofrequencyenergy followed by direct current energy in the same sessionmay have a high complication rate.