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 graf t (CABG) surgery that is associated with adverse patient outcomes. We evalu ated whether preexisting abnormalities of cardiac structure or function det ected with transesophageal echocardiography (TEE) are prevalent in patients later developing atrial fibrillation after CABG surgery. TEE imaging was p erformed after induction of general anesthesia, but before primary CABG sur gery, in 62 consecutive patients without cardiac valvular disease or preexi sting atrial fibrillation. Measurements included left atrial diameter, left ventricular wall thickness, left ventricular end-systolic and end-diastoli c dimensions and fractional area change. Pulsed-wave Doppler measurements o f pulmonary venous and trans-mitral blood flow velocity were obtained. Cont inuous monitoring with telemetry electrocardiography for the development of atrial fibrillation was performed. Eighteen patients (29%) developed posto perative 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 at rial fibrillation. After adjusting for age and duration of aortic cross-cla mping, there were no differences in the transmitral Doppler diastolic filli ng variables between these same groups. These data suggest that atrial fibr illation commonly occurs after CABG surgery in the absence of atrial enlarg ement or Doppler-derived cardiac functional abnormalities. The data imply t hat the use of TEE immediately before surgery would be an insensitive means for routine identification of patients susceptible to this arrhythmia.