Epicardial Treatment of Atrial Fibrillation Using Cryoablation in an Acute Off-pump Sheep Model - Doll, N; Kornherr, P; Aupperle, H; Fabricius, A M; Kiaii, B; Ullmann, C; Schneider, K; Dhein, S; Schoon, H -A; Rastan, A; Walther, T; Mohr, F W (The Thoracic and Cardiovascular Surgeon, 2003)