The figures printed below are color images of grayscale figures appearing in the August 2007 issue of the Journal, pages 851-852 (Gerstenfeld et al., “Comparison of High Power, Medium Power, and Irrigated-Tip Ablation Strategies for Pulmonary Vein Isolation in a Canine Model”).
[ A: Intracardiac echocardiographic image of the left atrium demonstrating a large thrombus measuring 1.7 cm in length in the left atrium. This thrombus was not present at the end of the initial ablation procedure, but was noted prior to sacrifice four weeks after ablation. No anticoagulation was used during the survival period. B: Gross pathology demonstrating the large thrombus firmly adherent to the left atrial wall between the left pulmonary veins and left atrial appendage. The mass is partially occluding the left lower pulmonary vein. ]
[ Top right panel: Gross photograph demonstrating stenosis of the left superior pulmonary vein with an early bifurcation. The superior branch is narrowed to a pinhole, while the inferior branch of the superior vein is also significantly narrowed. Bottom left panel: Histopathology demonstrating marked fibrointimal hyperplasia as the cause of the pulmonary vein stenosis (arrowheads). The basophilic areas (arrow) represent myxoid changes. LSPV = left superior pulmonary vein; LIPV = left inferior pulmonary vein; LAA = left atrial appendage. ]
[ Top left: Gross picture of the epicardial surface of the posterior left atrium after sacrifice, with the overlying lung tissue exposed. Note the epicardial scarring at the base of the left atrial appendage at the junction with the left superior pulmonary vein (white arrow). There is also gross evidence of an ablation lesion to the lung tissue directly overlying the posterior left atrium (white arrowhead). Bottom right: Photomicrograph (1.3 × original magnification) of a section of the lung taken through the ablated area demonstrating evidence of fat necrosis to the peribronchial and perivenous soft tissue (black arrow). LAA = left atrial appendage. ]
[ A: Typical ablation lesion using the Hi power ablation (70 W, 60°C, 20 seconds) strategy. Note the transmural lesion, with a large area of central necrosis (arrowheads) and surrounding granulation tissue. B: Magnified view (6.7 × original magnification) demonstrating occlusion of a small epicardial coronary artery. The organized thrombus suggests that this lesion is weeks old, and not an artifact of preparation. C: Another lesion showing evidence of transmural necrosis, subendocardial hemorrhage (small arrows), and granulation tissue (open arrow) adjacent to normal atrial myocardium (filled arrow). ]
[ Typical lesions using irrigated-tip ablation (35 W, 45°C, 60 seconds). A: Gross endocardial appearance after ablation demonstrating superficial white patches without eschar. Note that due to the large tip catheter and small atrium, some ablation lesions have encroached into the ostium of the left lower pulmonary vein. B: Histopathology (original magnification × 2.7) demonstrating evidence of healed transmural lesions (open arrows) adjacent to granulation tissue (closed large arrow) and normal myocardium (small arrow). Note that there is no evidence of subendocardial hemorrhage or necrosis. LSPV = left superior pulmonary vein; LIPV = left inferior pulmonary vein; LAA = left atrial appendage. ]