Mitral Isthmus Ablation Using Steerable Sheath and High Ablation Power: A Single Center Experience
Article first published online: 15 JUN 2012
© 2012 Wiley Periodicals, Inc.
Journal of Cardiovascular Electrophysiology
Volume 23, Issue 11, pages 1193–1200, November 2012
How to Cite
WONG, K. C. K., QURESHI, N., JONES, M., RAJAPPAN, K., BASHIR, Y. and BETTS, T. R. (2012), Mitral Isthmus Ablation Using Steerable Sheath and High Ablation Power: A Single Center Experience. Journal of Cardiovascular Electrophysiology, 23: 1193–1200. doi: 10.1111/j.1540-8167.2012.02380.x
- Issue published online: 13 NOV 2012
- Article first published online: 15 JUN 2012
- Accepted manuscript online: 19 MAY 2012 12:15PM EST
- Manuscript received 11 February 2012; Revised manuscript received 5 May 2012; Accepted for publication 15 May 2012.
- 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 °C; coronary sinus [CS]: maximum power: 25/30 W, maximum temperature: 48 °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. 1193–1200, November 2012)