Involvement of Sympathetic Activity in the Onset of Atrial Fibrillation following Cardiac Surgery

(Division of Cardiovascular Surgery, Kamo Hospital, Toyota, Japan and Department of Cardiothoracic Surgery, Nagoya University Graduate School of Medicine*, Nagoya, Japanj

Takeru Shimomura Akihiko Usui* Yuichi Ueda*
Although atrial fibrillation is a complication frequently encountered after cardiac surgery in routine practice, no effective measure is available to prevent its onset, and surgeons often have great difficulties in managing their patients with this condition. On suspicion of the involvement of increased sympathetic activity in the onset, the pre-onset status of 57 patients was examined. The patients were supposedly at low risk of developing atrial fibrillation after cardiac surgery. Additionally, plasma concentrations and 24-hour cumulative urinary excretion of norepinephrine, a biochemical indicator of sympathetic activity, were measured before surgery and on days 3 and 7 of disease. As a result, a group of patients with atrial fibrillation were found to have higher pre-onset heart rates and significantly increased plasma norepinephrine concentrations and 24-hour cumulative urinary norepinephrine excretion compared to controls. Hence, increased sympathetic activity is considered to play a major role in the onset of atrial fibrillation following cardiac surgery.
@Jpn. J. Cardiovasc. Surg. 35: 309-314 (2006)