Pump Up: Ablation Reverses Poor LV Function in Atrial Fib

September 18, 2014

LAS VEGAS, NV — Left ventricular ejection fraction (LVEF) climbed and symptoms vastly improved, on average, in patients initially with atrial fibrillation (AF) and LVEF <35% with severe heart failure who underwent catheter ablation for their arrhythmia, in a small single-center series with follow-ups averaging 27 months[1].

Not all of the 32 patients improved that way; LVEF went down after ablation in a few patients who didn't stay in sinus rhythm, according to lead author Dr Arun Kanmanthareddy (University of Kansas Medical Center, Kansas City).

But the finding that AF-mediated cardiomyopathy may often be reversible by catheter ablation, with potential gains in ventricular function and symptoms, supports ablation as more of a first-line approach to AF in some patients, "rather than waiting until the medications fail," he said to heartwire . By then, the atrial remodeling caused by AF may be more entrenched, and it will likely be much harder to achieve rhythm control.

"Low ejection fraction should not be a contraindication for patients to undergo AF ablation, because we still see significant benefits of rhythm control in this population," he said. "And we should intervene early."

Potentially, he added, AF ablation could improve ventricular function in patients with heart failure to the point that they might no longer be candidates, at least based on LVEF, for an implantable defibrillator, "and that's huge." In the current series, average LVEF rose from 28.4% before ablation to 46.6% by the end of follow-up, and mean NYHA functional class improved from 3.2 to 1.8 (p<0.001 for both differences).

The 32 patients in the analysis, presented earlier this week in a poster here at the Heart Failure Society of America (HFSA) 2014 Scientific Meeting , represented all with LVEF <35% among the center's approximately 1400 catheter-ablation cases. About 94% of the predominantly male group were treated for persistent AF; 37% had ischemic cardiomyopathy, and 19% had a history of coronary bypass surgery. At baseline, >90% were on beta-blockers, 19% on calcium-channel blockers, 62% on amiodarone or other class III antiarrhythmic, and 53% on digoxin. All were on oral anticoagulation, nearly all with warfarin.

Only 10 patients (31%) were in sinus rhythm, on medications, prior to ablation; all patients were in sinus rhythm after the procedure, and 24 patients (75%) remained so throughout their follow-up (p<0.001), more than half of whom no longer needed rate-control drug therapy, Kanmanthareddy said.

The findings may support a first-line ablation approach in AF, he said, "but we don't know. The AFFIRM trial didn't find a significant difference between rhythm and rate control, and so far no [completed] randomized trial has looked as whether AF ablation or rate control is better." The Catheter Ablation vs Anti-arrhythmic Drug Therapy for Atrial Fibrillation (CABANA) trial looking at the question is ongoing, he said.

CABANA is randomizing about 2200 patients resembling those in AFFIRM to ablation or medical therapy and following them for clinical outcomes; it's aiming for completion in 2018.

Kanmanthareddy disclosed having no conflicts of interest. CABANA is in part sponsored by St Jude Medical and Biosense Webster.

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