Atrial fibrillation after coronary artery bypass graft surgery is unrelated to cardiac abnormalities detected by transesophageal echocardiography

Atrial fibrillation is a common complication of coronary artery bypass graft (CABG) surgery that is associated with adverse patient outcomes. We evaluated whether preexisting abnormalities of cardiac structure or function detected with transesophageal echocardiography (TEE) are prevalent in patients later developing atrial fibrillation after CABG surgery. TEE imaging was performed after induction of general anesthesia, but before primary CABG surgery, in 62 consecutive patients without cardiac valvular disease or preexisting atrial fibrillation. Measurements included left atrial diameter, left ventricular wall thickness, left ventricular end-systolic and end-diastolic dimensions and fractional area change. Pulsed-wave Doppler measurements of pulmonary venous and trans-mitral blood flow velocity were obtained. Continuous monitoring with telemetry electrocardiography for the development of atrial fibrillation was performed. Eighteen patients (29%) developed postoperative atrial fibrillation. There were no significant differences in left atrial or left ventricular TEE variables or pulsed-wave Doppler pulmonary venous flow measurements between patients with and without postoperative atrial fibrillation. After adjusting for age and duration of aortic cross-clamping, there were no differences in the transmitral Doppler diastolic filling variables between these same groups. These data suggest that atrial fibrillation commonly occurs after CABG surgery in the absence of atrial enlargement or Doppler-derived cardiac functional abnormalities. The data imply that the use of TEE immediately before surgery would be an insensitive means for routine identification of patients susceptible to this arrhythmia.