Atrial Fibrillation Following Open Heart Surgery: Long-term Incidence and Prognosis

Introduction: 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.

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

Methods: 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

Results: 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).

Conclusions: 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.