PURPOSE: Post-operative atrial fibrillation (AFIB) associated with cardiac surgery leads to increased morbidity and length of post-operative hospital stay. Previous studies have investigated risk factors and interventions to decrease the incidence of post-operative AFIB but few have addressed the influence of sympathometic infusions or the influence of post-operative time to administration of various risk modifying medications (aspirin (ASA), beta-blockers (BB), ace-inhibitors (ACE-I), and statins.) Our study addresses the influence of these variables on the incidence of post-operative AFIB.
METHODS: A retrospective medical record review of all cases in 2003 of post-operative AFIB after coronary bypass (CABG) for a single tertiary medical center in Northern America. Valvular surgeries or patients developing intraoperative AFIB were excluded. 60 cases (21% incidence) of new onset AFIB were identified and controls (n=57) were matched for age and sex.
RESULTS: There was no significant difference between AFIB patients and controls in age, sex, percent diabetes mellitus, pre-operative and post-operative medication exposure (ASA, BB, ACE-I, statins), or Mg/K concentrations. The total number of patients included was 117 (AFIB + control). No difference in times to administer BB (p .23) or ACE-I (p .33) medications was identified. In the post-operative period, later administration of ASA and statins as well as dopamine infusion immediately post-operatively was associated with decreased incidence of AFIB (multivariant analysis: ASA (rr .92 CI .86-.996 p .04); statins (rr .98 CI .97-.997 p .02); dopamine (rr .35 CI .13-.91 p .03)). Administration of either epinephrine or norepinephrine is associated with an increased likelihood of developing AFIB (rr 2.75 CI 1.03–7.35 p .04).
CONCLUSION: Exposure to epinephrine and norepinephrine infusions increased the risk of AFIB. Early post-operative administration of ASA and statins increased the likelihood of post-operative AFIB. Low dose dopamine infusion may decrease the risk. The timing of BB and ACE-I administration had no effect on the incidence of AFIB.
CLINICAL IMPLICATIONS: Avoidance of epinephrine and norepinephrine infusions post-operatively in CABG may decrease the incidence of AFIB. Further prospective study of our observations is warranted.
DISCLOSURE: Shea Eckardt, None.