Power and Temperature Guided Radiofrequency Catheter Ablation of the Right Atrium in Pigs

The aim of the present study was twofold: to assess the safety of ablating the atrial free wall using RF current; and to assess the effect of a single dose of intravenous beparin foUowed by aspirin once daily to prevent tbrombas formation after RF ablation. Temperature and power guided catheter ablation were evaluated. Twenty pigs were randomized to power or temperature guided unipolar RF catheter ablation. Ten animals received a bolus of beparin (150 U/kg) followed by 150-mg aspirin daily. and ten served as controls. A mid-sternal tboracotomy was performed 5–7 days later. the ability of a lesion to resist an increased transmural atrial pressure was examined by inflating a cuff around the palmonal artery. Transmurai lesions were found in all animals. Rigbt atrial pressure was increased from 5 to 30 mmHg witb no sign of perforation. In 11 of 20 (55%) animals, 1–3 lesions were foand in the lungs (diameter 4–18 mm). the localization of these lesions corresponded to the lesions in the atria. there were no differences in the energy delivery modes witb regard to the number of animals witb lung lesions. Lesions witb thrombus formation were found in four animals in the heparin/aspirin group and in nine animals in the control group. The incidence of thrombi was significantly smaller in the treatment group. there were no differences between temperature and power guided catheter ablation witb regard to the size of the atrial lesions or to the incidence of tbrombus formation. Transmural lesions induced in the rigbt atrium by RF energy are resistant to increases in transmural pressure. However, lung tissue overlying the ablated target may be injured by the RF energy delivered. The combination of a single dose intravenous beparin followed by aspirin daily may reduce the incidence of tbrombus formation.