Egill Gauti Þorsteinsson¹

Nanna Sveinsdóttir¹

Leon Arnar Heitmann¹

Sunna Rún Heiðarsdóttir¹

Mary Rezk^2,3

Amar Taha^2,4

Anders Jeppsson^2,3,5

Tómas Guðbjartsson^1,5

¹Faculty of Medicine, University of Iceland, ²Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden, ³Departments of Cardiothoracic Surgery and ⁴Cardiology, Sahlgrenska University Hospital, Gothenburg, Sweden, ⁵Department of Cardiothoracic Surgery, Landspitali University Hospital.

Correspondence: Tómas Guðbjartsson, tomasgud@landspitali.is

Key words: New-onset postoperative atrial fibrillation (POAF), coronary artery bypass grafting (CABG), incidence, time length, POAF duration, treatment, short-term outcome, 30 day mortality.

INTRODUCTION: The aims of this retrospective study were to investigate the incidence, clinical course and short term outcomes of new-onset postoperative atrial fibrillation (POAF) following coronary artery bypass surgery (CABG).

MATERIALS AND METHODS: A nation-wide study on 1622 patients who underwent CABG from 2006–2020 at Landspitali University Hospital. Clinical data were extracted from registries and 121 patients with pre-existing AF excluded, leaving 1501 patients for further analysis. Patient charts and postoperative ECGs were manually reviewed for determining details of POAF, which was defined as a postoperative episode of AF before discharge lasting at least 5 minutes. Patients with POAF (n=483) were compared to non-POAF patients (n=1018).

RESULTS: Altogether 483 (32.2%) patients developed POAF; the annual incidence decreasing over time (tau= -0,45, p=0.023). Most patients were diagnosed on the second day postoperatively (43.5%) and over 90% were diagnosed within 4 days. The median number of POAF episodes was 3 (IQR: 1-5), the first episode lasting 1-6 hours in half of the cases and the total POAF-duration being 12 hours median (IQR: 5-30). Over 94% of cases converted to sinus rythm before discharge, with 25 (5.3%) patients being discharged in AF. Most patients were treated with beta-blockers (98.8%), amiodarone (95%) and 14.9% with electric cardioversion. POAF-patients were older, had higher EuroSCORE II and a longer hospital stay, however, they had similar rates of early postoperative stroke and 30 day mortality.

CONCLUSION: The incidence of POAF remains high and was associated with prolonged hospital stay, but not significantly higher 30 day mortality or early postoperative stroke compared to patients in sinus rhythm. POAF-episodes were predominantly transient and almost 95% of patients were discharged in sinus rythm.