Atrial fibrillation following open heart surgery: long-term incidence and prognosis

While early postoperative atrial fibrillation (post op AF) following valve and coronary artery bypass surgery is a known common cause of increased morbidity and mortality, the late recurrence of AF long term in this group of patients has not been well studied.

The objective of this study was to assess the late recurrence and predictors of AF in patients undergoing open heart surgery.

From a prospective cardiovascular surgery registry, 519 patients with no prior history of AF who underwent open heart surgery for cardiac bypass/valvular surgeries between May 2000 and April 2004 were followed until May 2009. A Cox proportional hazards model was used to assess the impact of early post op AF on the long-term AF after adjusting for significant covariates

Of these patients, 25.6 % (133) had early (0-3 months) post op AF (group A). The remainder of patients were considered as controls (group B, n = 386). Late occurrence of AF (3-84 months) was 5.3 % (n = 28) after a mean follow up duration of 5 ± 1.9 years. The late occurrence of AF in group A (recurrent AF) was significantly higher than in group B (11 vs 3 % n = 15 vs 13, p = 0.0002). Early postoperative AF was a significant predictor of late recurrence of AF in multivariate analysis (hazard ratio (HR) 3.9, CI 1.8-8.4, p = 0.0003). Group A also had higher mortality compared to group B (21 vs 13 %, n = 28 vs n = 51, p = 0.003) with early postoperative AF showing a trend towards higher mortality on multivariate analysis (HR 1.7, p = 0.06).

Late recurrence of AF is higher than was previously thought to be in patients experiencing early post operative AF with a trend towards higher long-term mortality. Post op AF should not be dismissed as a benign entity and these patients should be followed closely.