Gamma-glutamyl transferase and atrial fibrillation in patients with coronary artery disease.

Background: The association between gamma-glutamyl transferase (GGT) and atrial fibrillation (AF) in patients with coronary artery disease (CAD) is uncertain.

Methods: This study included 5501 consecutive patients with CAD, all of whom had baseline GGT measurements available. The primary endpoint was presence of AF.

Results: Overall 809 patients (14.7%) had AF on hospital admission. Patients with AF had significantly higher GGT activity compared with patients in sinus rhythm (median [25th-75th percentile]: 52.0 [32.9-96.0] U/L versus 34.8 [23.8-55.9] U/L, P<0.001). The prevalence of AF increased from 8.6% of patients in the first GGT decile to 30.3% of patients in the tenth decile (P<0.001). After multivariable adjustment, GGT activity remained independently associated with the probability of the presence of AF (adjusted adds ratio=1.66, 95% confidence interval 1.53-1.81, P<0.001 for each standard deviation increment in the GGT logarithmic scale). GGT predicted the probability of AF with an area under the receiver operating characteristic (ROC) curve of 0.6496, 95% confidence interval 0.6287 to 0.6705, P<0.001 indicating moderate strength to discriminate between patients with and without AF.

Conclusions: In patients with CAD, elevated GGT activity is independently associated with the presence of AF. GGT may be a circulating marker of the risk for AF.