Cryoablation of atrial fibrillation in cardiac surgery: outcomes and myocardial injury biomarkers.

Objective: Elevations of myocardial injury biomarkers after cardiac surgery without ablation of atrial fibrillation (AF) are related to perioperative myocardial ischemia and associated with an increased risk of mortality and cardiac events. However, there have not been any studies that examined the release of cardiac biomarkers after AF cryoablation procedures with concomitant cardiac surgery. The authors determined the levels of these biomarkers for 2 different procedures involving cryoablation and assessed their clinical implications.

Design: A prospective cohort study with cardiac surgical patients.

Setting: A tertiary care university hospital.

Participants: One hundred fifty-two cardiac surgical patients.

Interventions: Patients underwent 1 of 2 different cryoablation approaches: the modified Cox-Maze (CM) III procedure (n = 63) or the isolated left atrial (LA) maze procedure (n = 89). Plasma levels of cardiac biomarkers were measured at 1, 6, 12, and 24 hours after surgery. Twenty-four-hour Holter monitoring was performed at 1 month and 1 year after surgery.

Measurements And Main Results: Both groups reached very high peak levels of CPK-MB (CM group, 368 ± 171.4 ng/mL and LA group, 203 ± 86.4 ng/mL) and troponin T (CM, 8 ± 4.5 ng/mL and LA, 3.4 ± 2.4 ng/mL). The CPK, CPK-MB, and troponin T levels were significantly higher in the modified CM group compared with the LA maze group. In the first 24 hours after surgery, the average CPK-MB and troponin T values were 78.2 ng/mL higher and 2.3 ng/mL higher, respectively, in the CM group compared with the LA group. In both groups, 79% of the patients remained free of AF at 12 months after surgery.

Conclusions: Cryoablation in cardiac surgery causes the release of very high levels of myocardial injury biomarkers. The modified CM lesion causes a greater elevation of serum biomarker levels than the isolated LA maze procedure, but this increase does not seem to have an adverse effect on rhythm or overall outcome. Cryoablation is a safe and effective surgical treatment for AF.