title: Effects of combined radiofrequency and direct current energy catheter ablation on ventricular myocardium in pigs.
abstract: When radiofrequency catheter ablation of ventricular arrhythmias is unsuccessful, an option may be to combine it with direct current energy. We therefore investigated the effects of such a combination. Radiofrequency energy was delivered in a bipolar or unipolar fashion to the left and right ventricles through an ablation catheter with a tip electrode 2 mm long, using a temperature-guided radiofrequency generator. Radiofrequency ablation was followed by a single cathodal direct current shock (66 J) with the ablation catheter positioned similarly in six closed-chest pigs. In a control group (six animals) only direct current ablation was performed, with one or two energy applications (66 J) in each ventricle. Two of six animals in the radiofrequency/direct current group died due to perforation in the follow-up period, 1 and 3.5 h after the direct current ablation, respectively. Gross pathological examination of the hearts revealed transmural lesions in all animals. In the radiofrequency/direct current group four lesions were perforated, three of which were located in the left ventricle. There was a significant increase in the number of perforations in the radiofrequency/direct current group compared to the control group, where perforation was never observed. Haemorrhagic pericardial fluid was found in five of the six animals in the radiofrequency/direct current group compared to none in the control group. These findings show that myocardial ablation with radiofrequency energy followed by direct current energy in the same session may have a high complication rate.
authors.affiliation: Institute for Surgical Research, Rikshospitalet, Oslo, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Kongsgaard
authors.forename: A
authors.initials: A
authors.lastname: Foerster
authors.forename: H
authors.initials: H
authors.lastname: Aass
authors.forename: S
authors.initials: S
authors.lastname: Madsen
authors.forename: J P
authors.initials: JP
authors.lastname: Amlie
mesh_terms: D000818:Animals; D017115:Catheter Ablation; D004562:Electrocardiography; D006335:Heart Injuries / Q000209:etiology / Q000473:pathology; D006352:Heart Ventricles / Q000293:injuries / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D013552:Swine; D014693:Ventricular Fibrillation / Q000209:etiology / Q000503:physiopathology