Mitral Isthmus Ablation Using Steerable Sheath and High Ablation Power: A Single Center Experience

作者：Wong Kelvin C K; Qureshi Norman; Jones Michael; Rajappan Kim; Bashir Yaver; Betts Timothy R^*

来源：Journal of Cardiovascular Electrophysiology, 2012, 23(11): 1193-1200.

DOI：10.1111/j.1540-8167.2012.02380.x

• atrial fibrillation
• left atrial flutter
• mitral isthmus
• radiofrequency catheter ablation
• steerable sheath

Case Series of Mitral Isthmus Ablation. Background: Mitral isthmus ablation is challenging. The use of steerable sheath and high ablation power may improve success rate. Methods: This single-center, prospective study enrolled 200 patients who underwent ablation for atrial fibrillation (AF), including mitral isthmus ablation. Mitral isthmus ablation was performed using an irrigated ablation catheter via a steerable sheath (endocardium: maximum power: 40/50 W limited to annular end, maximum temperature: 48 degrees C; coronary sinus [CS]: maximum power: 25/30 W, maximum temperature: 48 degrees C). Endpoint was bidirectional mitral isthmus block. Results: Mitral isthmus block was acutely achieved in 182/200 patients (91%). Sixty-nine percent of patients required CS ablation. Mean total ablation time was 13 +/- 6 minutes. There was 1 case of acute circumflex artery occlusion. Mean left atrium (LA) diameter was significantly bigger in patients with unsuccessful mitral isthmus ablation (49 +/- 4 mm vs. 43 +/- 6 mm; P = 0.0007). In redo procedures, the incidence of reconduction at the mitral isthmus, roof and cavotricuspid isthmus was 44%, 37%, and 29%, respectively. Overall incidence of perimitral flutter was 9%. Prior complex fractionated atrial electrogram ablation was a predictor for microreentrant atrial tachycardia (AT) whereas gaps in linear lesions predicted macroreentrant flutters. After a mean follow-up of 20 +/- 9 months, 73% of patients remained free from AF or AT. Conclusion: We reported on a series of mitral isthmus ablation using steerable sheath and high ablation power (50 W). Larger LA diameter was a predictor of failure to achieve mitral isthmus block. The mitral isthmus had a moderately high incidence of re-conduction but was only associated with a relatively low incidence of perimitral flutter. (J Cardiovasc Electrophysiol, Vol. 23, pp. 11931200, November 2012)

• 出版日期2012-11