Predictors of Left Atrial Coagulation Activity Among Paroxysmal Atrial Fibrillation Patients

Background:The difference between left atrial (LA) and systemic coagulation activity in paroxysmal atrial fibrillation (PAF) is unclear.Methods and Results:We enrolled 100 patients with PAF who underwent AF ablation. Warfarin was stopped 1 day before the procedure. LA volume index and LA emptying fraction were measured by 64-slice multidetector computed tomography. Immediately after transseptal puncture, blood samples were simultaneously collected from the LA and systemic circulation (SC). In addition, to evaluate the effect of warfarin on D-dimer levels we recruited an additional 27 PAF patients on continuous warfarin. Even in patients with low CHADS2scores (mean 0.59±0.68) and during sinus rhythm, the prevalence of positive LA-D-dimer (≥0.5 µg/ml) was greater than that of SC-D-dimer (23% vs. 10%, P<0.01). The LA-D-dimer-positive patients had a larger mean LA volume index and reduced LA emptying fraction than the LA-D-dimer-negative patients. Multiple logistic regression analysis revealed that LA volume index was independently correlated with positive LA-D-dimer (odds ratio 2.245, 95% confidence interval 1.194−4.626, P=0.0112). The prevalence of positive LA-D-dimer was significantly lower in patients taking continuous warfarin, than in those on discontinuous warfarin (3.7% vs. 23%, P=0.025).Conclusions:An enlarged LA volume index was associated with high LA coagulation status in patients with paroxysmal AF. Adequate warfarin control during AF catheter ablation may reduce the prevalence of positive LA-D-dimer. (Circ J 2015; 79: 61–69)