3.6. Prevention Of Atrial Fibrillation After Cardiac Surgery

Public examination of a doctoral dissertation in the field of cardio-thoracic surgery

Doctoral candidate: Lic Med Jari Halonen

Time and venue: 3.6.2011 at 12 noon, Kuopio University Hospital, Auditorium 1

Atrial fibrillation (AF) is the most common arrhythmia to occur after cardiac surgery. It is associated with postoperative complications, including increased risk of stroke, prolonged hospital stay and increased costs. The purpose of this study was to find a reliable, effective, safe and well tolerated tools for the prevention of postoperative AF after cardiac surgery. The study consisted of three prospective, randomized clinical trials.

In study I we randomized 240 patients to receive either oral or intravenous metoprolol for 48 hours after cardiac surgery. The incidence of postoperative AF was significantly lower in the intravenous metoprolol group (16.8%) than in oral group (28.1%), (p=0.036). Intravenous metoprolol administration was feasible and easy and turned out to be welltolerated in postoperative patients.

In study II a total of 241 patients were scheduled to receive either intravenous hydrocortisone or placebo postoperatively for 84 hours. The incidence of postoperative AF was 30.0 % in the hydrocortisone group compared with 47.9% in the placebo group and the relative risk reduction was 37%. Intravenous hydrocortisone therapy turned out to be well tolerated. In addition, no serious complications were associated with intravenous corticosteroid therapy.

In study III intravenous metoprolol therapy showed to be as effective as intravenous amiodarone in the prevention of AF after cardiac surgery. Three hundred and sixteen patients were randomized to receive either metoprolol or amiodarone intravenously starting on the first postoperative morning after cardiac surgery. The incidence of postoperative AF was 23.9% in the metoprolol group and 24.8% in the amiodarone group with no statistical difference between the groups. However, because of the wide range of the confidence intervals, we can not conclude that intravenous metoprolol and amiodarone are equally effective in the prevention of AF after cardiac surgery.

In summary, we suggest that intravenous metoprolol therapy should be a part of routine medication to prevent AF in all patients undergoing cardiac surgery, unless contraindicated. Moderate-dosage corticosteroid (hydrocortisone) should be considered for the prevention of AF in high risk patients undergoing cardiac surgery. Amiodarone should be used for the prevention of postoperative AF only if beta-blocker therapy is contraindicated.

The doctoral dissertation of Licenciate of Medicine , Specialist, Master of Arts (Education) Jari Halonen, entitled Prevention of atrial fibrillation after cardiac surgery will be examined at the Faculty of Health Sciences. The opponent in the public examination will be Docent Jussi Rimpiläinen of the University of Oulu and the custos will be Docent Tapio Hakala of the University of Eastern Finland and of the North Carelia Central Hospital.

Publishing year: 2011

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