DENVER — Postoperative atrial fibrillation is often dismissed as a nuisance arrhythmia whose chief impact is a prolonged stay in the hospital. But this common postsurgical complication may have previously unappreciated long-term adverse consequences, according to a Swedish study.
Indeed, postop atrial fibrillation (AF) occurring within the first several days after coronary artery bypass graft surgery in patients without any history of AF was associated with nearly a twofold increased late all-cause mortality, mainly due to more deaths that could be attributable to stroke, arrhythmias, and heart failure, Dr. Anders Ahlsson said at the annual scientific sessions of the Heart Rhythm Society.
He reported on 1,443 patients who were in sinus rhythm with no history of AF or pacemaker therapy when they underwent a first CABG procedure in 1997–2000. On postop days 1–5, 29% developed AF. They were on average more than 4 years older than those who did not; however, left ventricular ejection fractions in the two groups were similar.
At a median of 8 years follow-up, all-cause mortality was 33.3% in the postop AF group and 19.2% in the comparator arm. (See box.)
In a multivariate regression analysis, postop AF proved to be a risk factor for mortality independent of patient age, diabetes, and other potential confounders. It conferred an adjusted 1.6-fold increased mortality risk, according to Dr. Ahlsson, a cardiothoracic surgeon at Orebro (Sweden) University.
Audience members wondered whether postop AF is truly the cause of the increased late mortality, in which case preventing the arrhythmia should produce an important mortality benefit, or if postop AF may just be an epiphenomenon reflecting some underlying abnormality that's the real cause of the increased risk.
That's the key unanswered question, Dr. Ahlsson agreed. Research in this area is complicated by a lack of predictors of which CABG patients will get postop AF.
“There have been a number of suggestions, but they are too vague to find these patients before it happens,” he said.
The practice at Obero University Hospital is to perform radiofrequency ablation at the time of CABG in patients who have preoperative AF. Nearly all patients undergoing CABG are on a β-blocker unless they have chronic lung disease or another contraindication.
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