Cryoablation at Growing Myocardium: No Evidence of Coronary Artery Obstruction or Intimal Plaque Formation Early and Late after Energy Application

BACKGROUND: Animal studies and clinical observations have demonstrated that radiofrequency current application at growing myocardium may result in coronary artery obstruction. Recently, cryoenergy has emerged as an effective alternative to radiofrequency ablation of arrhythmogenic substrates in pediatric patients. Up to now, there has been a lack of experimental data concerning the effects of cryoenergy application at growing myocardium. METHODS: During general anesthesia, selective coronary angiography of the right and left coronary artery was performed in 10 piglets (age: 6 weeks, body weight: 14-18 kg). Subsequently, cryoenergy was delivered at -75 degrees C for 4 minutes using a 7-F catheter with a 6-mm-tip electrode at the atrial aspect of the tricuspid valve annulus in a posterior and lateral position. Additional cryoenergy lesions were induced via a retrograde approach at the lateral and posterior atrial and ventricular aspect of the mitral valve annulus, respectively. Five animals were restudied after 48 hours by coronary angiography and intracoronary ultrasound and in the remaining five piglets after 3 and 6 months, respectively. RESULTS: Selective coronary angiography and intracoronary ultrasound studies did not demonstrate any evidence for coronary artery obstruction after 48 hours, 3 months, or 6 months after cryoenergy application. In addition, histological examinations of the cryolesions after 48 hours and after 6 months did not demonstrate any intimal proliferations of the coronary arteries, respectively. CONCLUSIONS: By means of the present study, we did not observe any affection of the coronary arteries after cryoenergy application at growing myocardium in young piglets.