The Clinical Noncompliance of Oral Sotalol/Magnesium for Prophylactic Treatment of Atrial Fibrillation After Coronary Artery Bypass Grafting

Abstract

Postoperative atrial fibrillation has been refractory to many attempted pharmacologic prevention methods and, when effective, side effects have been described. The present aim was to study the clinical compliance of a suggested prophylactic treatment, oral sotalol, and magnesium. Coronary-bypass patients without clinical contraindications to receive oral sotalol (80 mg twice daily) and magnesium supplementation were enrolled (n = 49) with an intention-to-treat strategy and being compared with a matched control group (n = 844). A protocol listed exclusion criteria of clinical compliance that was postoperatively evaluated prior to and during treatment. Twenty-seven of the 49 enrolled patients (55%) were compliant to sustain the treatment according to the protocol. The remaining patients were postoperatively excluded, mainly because of hemodynamic reasons, of whom 14 were noncompliant to initiate any treatment. The AF occurrence in the compliant group was 7% versus 36% in noncompliant patients (p = 0.035), and 24% in the control group (p = 0.076). However, with an intention-to-treat policy the overall AF incidence became 18%. The subgroups of enrolled patients demonstrated skewing phenomena. The noncompliant group had higher requirement for inotropic support (p = 0.029) and longer aortic cross-clamp time (p = 0.048) compared to compliant patients. Further, the body weight of noncompliant patients was markedly lower than in the compliant counterpart (p = 0.015). The tested treatment protocol showed limited compliance among routine cardiac-surgery patients, and further, introduced a biased selection of patients that skewed the results and may have partly explained the treatment effect.