Authors' objectives:

A 2005 systematic review conducted at the request of the Ontario Health Technology Advisory Committee concluded that catheter ablation for patients with atrial fibrillation (AF) appears to be effective and safe, but that it is still a new and evolving technology. The Medical Advisory Secretariat conducted this review to assess the effectiveness, cost-effectiveness, and demand in Ontario for catheter ablation of complex arrhythmias guided by advanced nonfluoroscopy mapping systems. Particular attention was paid to ablation for AF.

Authors' results and conclusions: Summary of Findings Evidence is based on a small number of small randomised controlled trials (RCTS) and non-RCTS with methodological flaws. Advanced nonfluoroscopy mapping/navigation systems provided real time 3-dimensional images with integration of anatomic and electrical potential information that enable better visualization of areas of interest for ablation Advanced nonfluoroscopy mapping/navigation systems appear to be safe; they consistently shortened the fluoroscopy duration and radiation exposure. Evidence suggests that nonfluoroscopy mapping and navigation systems may be used as adjuncts to rather than replacements for fluoroscopy in guiding the ablation of complex arrhythmias. Most studies showed a nonsignificant trend toward lower overall failure rate for advanced mapping-guided ablation compared with fluoroscopy-guided mapping. Pooled analyses of small RCTs and non-RCTs that compared fluoroscopy- with nonfluoroscopy-guided ablation of atrial fibrillation and atrial flutter showed that advanced nonfluoroscopy mapping and navigational systems: - Yielded acute success rates of 69% to 100%, not significantly different from fluoroscopy ablation. - Had overall failure rates at 3 months to 19 months of 1% to 40% (median 25%). -Resulted in a 10% relative reduction in overall failure rate for advanced mapping guided-ablation compared to fluoroscopy guided ablation for the treatment of atrial fibrillation. -Yielded added benefit over fluoroscopy in guiding the ablation of complex arrhythmia. The advanced systems were shown to reduce the arrhythmia burden and the need for antiarrhythmic drugs in patients with complex arrhythmia who had failed fluoroscopy-guided ablation Based on predominantly observational studies, circumferential pulmonary vein (PV) ablation guided by a nonfluoroscopy system was shown to do the following: - Result in freedom from atrial fibrillation (with or without antiarrhythmic drug) in 75% to 95% of patients (median 79%). This effect was maintained up to 28 months. - Result in freedom from atrial fibrillation without antiarrhythmic drugs in 47% to 95% of patients (median 63%). - Improve patient survival at 28 months after the procedure as compared with drug therapy. - Require special skills; patient outcomes are operator dependent, and there is a significant learning curve effect. Complication rates of pulmonary vein ablation guided by an advanced mapping/navigation system ranged from 0% to 10% with a median of 6% during a follow-up period of 6 months to 29 months. The complication rate of the study with the longest follow-up was 8%. The most common complications of advanced catheter-guided ablation were stroke, transient ischemic attack, cardiac tamponade, myocardial infarction, atrial flutter, congestive heart failure, and pulmonary vein stenosis. A small number of cases with fatal atrial-esophageal fistula had been reported and were attributed to the high radiofrequency energy used rather than to the advanced mapping systems.

Authors' recommendations: For patients suffering from symptomatic, drug-refractory atrial fibrillation and are otherwise healthy, catheter ablation offers a treatment option that is less invasive than is open surgical ablation. Small RCTs that may have been limited by type 2 errors showed significant reductions in fluoroscopy exposure in nonfluoroscopy-guided ablation and a trend toward lower overall failure rate that did not reach statistical significance. Pooled analysis suggests that advanced mapping systems may reduce the overall failure rate in the ablation of atrial fibrillation. Observational studies suggest that ablation guided by complex mapping/navigation systems is a promising treatment for complex arrhythmias such as highly symptomatic, drug-refractory atrial fibrillation for which rate control is not an option In people with atrial fibrillation, ablation guided by advanced nonfluoroscopy mapping resulted in arrhythmia free rates of 80% or higher, reduced mortality, and better quality of life at experienced centres. Although generally safe, serious complications such as stroke, atrial-esophageal, and pulmonary vein stenosis had been reported following ablation procedures. Experts advised that advanced mapping systems are also required for catheter ablation of: - Hemodynamically unstable ventricular tachycardia from ischemic heart disease - Macro re-entrant atrial tachycardia after surgical correction of congenital heart disease - Atypical atrial flutter Catheter ablation of atrial fibrillation is still evolving, and it appears that different ablative techniques may be appropriate depending on the characteristics of the patient and the atrial fibrillation. Data from centres that perform electrophysiological mapping suggest that patients with drug-refractory atrial fibrillation may be the largest group with unmet need for advanced mapping-guided catheter ablation in Ontario. Nonfluoroscopy mapping-guided pulmonary vein ablation for the treatment of atrial fibrillation has a significant learning effect; therefore, it is advisable for the province to establish centres of excellence to ensure a critical volume, to gain efficiency and to minimize the need for antiarrhythmic drugs after ablation and the need for future repeat ablation procedures.

Authors' methods: Systematic review

Project Status: Completed

Year Published: 2006

URL for published report: http://www.health.gov.on.ca/english/providers/program/mas/tech/reviews/pdf/rev_ep_030106.pdf

URL for additional information: http://www.hqontario.ca/en/mas/mas_ohtas_tech_ep_030106.html

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Canada

Organisation Name: Medical Advisory Secretariat

Contact Address: Medical Advisory Secretariat, 20 Dundas Street West, 10th Floor, Toronto, ON M5G 2N6 CANADA. Tel: 416-314-1092l; Fax: 416-325-2364;

Contact Name: MASinfo.moh@ontario.ca

Contact Email: MASinfo.moh@ontario.ca

Copyright: Medical Advisory Secretariat, Ontario Ministry of Health and Long-Term Care