Focus Issue: Atrial Fibrillation
Clinical Research: Ablation Therapy of Atrial Fibrillation
Clinical Outcomes of Catheter Substrate Ablation for High-Risk Patients With Atrial Fibrillation

https://doi.org/10.1016/j.jacc.2007.10.044Get rights and content
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Objectives

The purpose of this study was to determine the long-term clinical outcomes of catheter ablation of atrial fibrillation (AF) substrate for high-risk patients with AF.

Background

The benefits of catheter ablation for high-risk AF patients with respect to mortality and stroke reductions remain unclear.

Methods

We performed AF substrate ablation guided by complex fractionated atrial electrogram (CFAE) mapping in 674 high-risk AF patients. The clinical end points were sinus rhythm (SR), death, stroke, or bleeding. Of these 674 patients, 635 were available for follow-up and made up the study cohort. The patients were relatively old (mean age 67 ± 12 years) and 129 had an ejection fraction (EF) <40%.

Results

After the mean follow-up period of 836 ± 605 days, 517 were in SR (81.4%). There were 15 deaths among the patients who stayed in SR compared with 14 deaths among those who remained in AF (5-year survival rate, 92% vs. 64%, respectively; p < 0.0001). SR was the most important independent favorable parameter for survival (hazard ratio 0.14, 95% confidence interval 0.06 to 0.36, p < 0.0001), whereas old age was unfavorable. Warfarin therapy was discontinued in 434 of the 517 patients in SR post-ablation (84%) whose annual stroke rate was only 0.4% compared with 2% in those with continuing warfarin treatment (p = 0.004).

Conclusions

CFAE-targeted ablation of AF is effective in maintaining SR in selected high-risk AF patients and might allow patients to stop warfarin therapy. SR after AF ablation is a marker of relatively low mortality and stroke risk. Our findings support conducting further randomized studies to determine whether AF ablation is associated with mortality and/or stroke reduction.

Abbreviations and Acronyms

AF
atrial fibrillation
CFAE
complex fractionated atrial electrogram
CI
confidence interval
CVA
cerebrovascular accident
EF
ejection fraction
HR
hazard ratio
INR
international normalized ratio
RF
radiofrequency
SR
sinus rhythm
TIA
transient ischemic attack

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Dr. Nademanee has received a research grant from Biosense Webster Inc. and honorarium from both Biosense Webster and St. Jude Medical.