A pilot study to estimate the feasibility of assessing the relationships between polymorphisms in hKv1.5 and atrial fibrillation in patients following coronary artery bypass graft surgery.

Background: Postoperative atrial fibrillation (AF) is a frequent complication following cardiac surgery. Risk factors leading to the development of postoperative AF are not well known and may be influenced by mutations of specific channels involved in atrial repolarization. Recently, the authors have identified three single nucleotide polymorphisms (SNPs) (R87Q, A251T and P307S) in the voltage-gated potassium channel hKv1.5 in a French-Canadian population. Two of these, R87Q and P307S, modified the gating process and the expression level of the hKv1.5 channel.
Objectives: Considering that these SNPs may accelerate atrial repolarization, it was hypothesized that they may predispose patients to postoperative AF.
Methods: The authors tested the presence of SNPs in the hKv1.5 channel among 185 patients undergoing coronary artery bypass graft surgery.
Results: In the postoperative period, 96 patients (52%) developed a new onset of AF. A higher prevalence of SNPs was found among patients who developed postoperative AF than in the population without this postoperative arrhythmia (6.25% versus 3.37%; P=0.42). Respective allelic frequencies for R87Q and P307S were 0.52% and 1.56% in the postoperative AF group versus 0% and 0.56% in the non-AF group. Families of the carrier patients were also screened, and several members were found who carried the SNPs but did not have AF. The A251T SNP is not likely to be responsible for AF because it does not modify hKv1.5 channel functions.
Conclusions: A genetic background that may be involved in the occurrence of postoperative AF was identified. Therefore, R87Q and P307S polymorphisms in hKv1.5, possibly in combination with other risk factors, may influence the development of postoperative AF.