Predictors of atrial fibrillation post coronary artery bypass graft surgery: new scoring system

BACKGROUND: Atrial fibrillation (AF) following coronary artery bypass graft surgery (CABG) is common and results in significant increases in hospital stay and financial encumbrance. OBJECTIVE: Determine and use the predictors of postoperative AF (POAF) following CABG to develop a new predictive screening tool. METHOD: A retrospective case–control study evaluated 388 patients (98 developed POAF and 290 remained in sinus rhythm) who undertook CABG surgery at Townsville University Hospital between 2016 and 2017. The demographic profile, risk factors for AF including hypertension, age≥75 years, transient ischaemic attack or stroke, chronic obstructive pulmonary disease (HATCH) score, electrocardiography features and perioperative factors were determined. RESULTS: Patients who developed POAF were significantly older. On univariate analysis HATCH score, aortic regurgitation, increased p-wave duration and amplitude in lead II and terminal p-wave amplitude in lead V1 were associated with POAF; as were increased cardiopulmonary bypass time (103.5±33.9 vs 90.6±26.4 min, p=0.001) and increased cross clamp time. On multivariate analysis age (p=0.038), p-wave duration ≥100 ms (p=0.005), HATCH score (p=0.049) and CBP Time ≥100 min (p=0.001) were associated with POAF. Receiver operating characteristic curve demonstrated that with a cut-off of ≥2 for HATCH score, POAF could be predicted with a sensitivity of 72.8% and a specificity of 34.7%. Adding p-wave duration in lead II >100 ms and cardiopulmonary bypass time >100 min to the HATCH score increased the sensitivity to 83.7% with a specificity of 33.1%. This was termed the HATCH-PC score. CONCLUSION: Patients with HATCH scores ≥2, and those with p-wave duration >100 ms, or cardiopulmonary bypass time >100 min were at greater risk of developing POAF following CABG.