Does prophylactic sotalol and magnesium decrease the incidence of atrial fibrillation following coronary artery bypass surgery: a propensity-matched analysis
V Aerra
2
M Kuduvalli
2
AN Moloto
2
AK Srinivasan
2
AD Grayson
0
1
Fabri
2
AY Oo
2
0
Senior Clinical Information Analyst, Clinical Governance Department. The Cardiothoracic Centre- Liverpool
,
Thomas Drive, Liverpool, L14 3PE
,
UK
1
Department of Research and Development. The Cardiothoracic Centre Liverpool
,
UK
2
Department of Cardiothoracic Surgery. The Cardiothoracic Centre Liverpool
,
UK
Background: Atrial fibrillation can occur in up to 40% of patients undergoing coronary surgery. Methods: We retrospectively analysed 103 consecutive coronary surgery patients under the care of one surgeon between April 2003 and September 2003. These patients received 40 mg of sotalol orally twice daily from the first post-operative day for 6 weeks and 2 g of magnesium intravenously immediately post surgery and on the first post-operative day. We developed a propensity score for the probability of receiving sotalol and magnesium after coronary surgery. 89 patients from the sotalol and magnesium group were successfully matched with 89 unique coronary surgery patients who did not receive either sotalol or magnesium with an identical propensity score. Results: Preoperative characteristics were well matched between groups. There was no significant difference with respect to in-hospital mortality between groups (sotalol and magnesium 1.1% versus control 4.5%; p = 0.17). The incidence of atrial fibrillation in the sotalol and magnesium group was 13.5% compared to 27.0% in the controls (p = 0.025). Conclusion: The combination of sotalol and magnesium can significantly reduce the incidence of post-operative atrial fibrillation following coronary surgery.
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Introduction
Atrial Fibrillation is the most common complication
following cardiac surgery with a reported incidence between
20% and 40% [1,2]. It usually occurs between the second
and fourth post-operative day. However, although this
complication occurs frequently, the mechanism behind
its development is less understood.
Numerous studies have identified and enumerated a
variety of risk factors for the development of atrial fibrillation.
These include increased age, male gender, history of atrial
fibrillation, discontinuation of preoperative eta-blocker
therapy, congestive heart failure, electrolyte depletion
(low potassium and magnesium), cardiopulmonary
bypass, left atrial dysfunction, severity of coronary artery
In an effort to prevent the occurrence of atrial fibrillation
in the post-operative period, various treatment modalities
have been implemented indicating its unclear
pathophysiology. The key role of eta blockers in prevention of atrial
fibrillation is well recognised in many randomised
control trials [8,9]. Sotalol has an acceptable safety profile
and is emerging as a key drug in the prevention of this
complication [9,10]. The role of magnesium supplements
is less clear [11-17].
The present study was done to examine the beneficial role
of sotalol and magnesium prophylaxis in the prevention
of atrial fibrillation in routine coronary artery bypass graft
(CABG) surgery.
Materials and methods
Patient population
Between 1st April 2003 and 30th September 2003, 103
consecutive patients undergoing first time isolated CABG
surgery under the care of one surgeon (AYO) were routinely
administered sotalol and magnesium (see sotalol and
magnesium). These patients were matched to a control group
taken from the remaining 487 consecutive patients who
SM (n = 89)
received first time isolated CABG surgery performed
during the same time period by other surgeons at our
institution (see statistical methods).
Exclusions
Patients undergoing CABG that was in addition to heart
valve repair or replacement, resection of a ventricular
aneurysm or other surgical procedure were not included.
Also excluded were patients who had received previous
cardiac surgery or patients with a history of atrial
arrhythmias.
Data collection
Definitions and data collection methods are available
from http://www.nwheartaudit.nhs.uk. Data was
collected prospectively during the patient's admission as part
of routine clinical practice and entered into our cardiac
surgery registry on the variables listed in Table 1.
Postoperative atrial fibrillation, in-hospital mortality, and
length of hospital stay were also documented.
Sotalol and Magnesium
Patients received 40 mg of sotalol orally twice daily from
the first post-operative day for 6 weeks and 2 g of
magnesium intravenously immediately post-coronary surgery
Control (n = 89)
SM, Sotalol and Magnesium; CPB, Cardiopulmonary Bypass; EuroSCORE, European System for Cardiac Operative Risk Evaluation; CAD, Coronary
Artery Disease; LIMA, Left Internal Mammary Artery. Categorical variables are shown as a percentage. Continuous variables are shown as a median
with 25th and 75th percentiles.
PFrigoupernes1ity-matched incidence of atrial fibrillation
Propensity-matched incidence of atrial fibrillation.
and on the first post-operative day. No patients from the
con (...truncated)