To Örebro University

Introduction: Atrial fibrillation (AF) is associated with an increased risk of stroke, heart failure and cardiovascular death. Initial treatment focuses on rhythm or rate control and anticoagulation after risk assessment. Catheter abla-tion (CA) is an option in highly symptomatic patients but is less effective in long-standing persistent AF(LSPAF). Total endoscopic ablation is an alternative, but its clinical role needs further evaluation. In patients undergoing aortocoronary bypass graft (CABG) surgery, up to 9 % present with preoperative AF. One-third experience postoperative AF, which is associated with increased hospital stay, risk of stroke and decreased long-term survival. The long-term effects on heart rhythm have not been studied.

Methods and Results: 571 patients undergoing CABG from 1999 to 2000 were followed for six years. Postoperative AF was the strongest independent risk factor for late AF and an age-independent risk factor for late mortality. 615 pa-tients from the same cohort, including patients with preoperative AF, were fol-lowed up at 15 years. Death due to cerebral ischaemia, heart failure and sudden death were most common in the pre- and postoperative AF groups. The presence of pre- or postoperative AF was an independent risk factor for late mortality.

In our first ten patients, total endoscopic ablation of AF using a right-sided unilateral approach was feasible and safe with acceptable results. 36 patients with symptomatic LSPAF were then randomized to total endoscopic ablation or rate control. Loop recorders were implanted in all patients. In the control group, all patients were in permanent AF for 12 months. In the ablation group, 12/15 patients (80%) were in SR without antiarrhythmic drugs at 12 months. Median freedom of AF at 3–12 months was 95%, and 8/15 (53%) had an AF burden of < 5%. Myocardial function, physical working capacity(PWC) and subjective physical and mental health improved.

Conclusions: Postoperative AF patients have an eightfold increased risk of future AF and a doubled long-term cardiovascular mortality. Both pre- or post-operative AF in CABG patients is a major risk factor for late cardiovascular morbidity and mortality. Total endoscopic ablation of AF is feasible and safe. In patients with LSPAF, it significantly reduced AF burden at 12 months compared with controls. Myocardial function, PWC and subjective physical and mental health improved.

Atrial fibrillation (AF) is associated with an increased risk of stroke, heart failure, and cardiovascular death. Ablation therapy can reduce AF symptoms, arrhythmia burden and mortality, and is performed endovascularly or surgically. Coronary revascularization involve surgical or endovascular techniques. New-onset AF is more commonly reported following surgery, but systematic heart rhythm monitoring strategies are rare. This thesis aimed to investigate the short- and long-term outcomes of totally endoscopic surgical ablation, as well as the short- and long-term incidence, risk factors, and burden of AF after cardiac revascularization.

Study I was a randomized controlled trial comparing totally endoscopic epicardial box lesion ablation of the left atrium to medical therapy in patients with long-standing persistent AF (LSPAF). At 1 year, 80% of ablated patients were in sinus rhythm (SR) without the need for antiarrhythmic drugs. Ablation improved physical working capacity, left ventricular systolic function, and self-reported quality of life.

Studies II, III, and IV were prospective cohort studies conducted in a real-world population of patients undergoing coronary artery bypass graft (CABG) or per-cutaneous coronary intervention (PCI). A systematic in-hospital and outpatient arrhythmia detection strategy was employed to determine the short-term (30-day) and long-term (24-month) cumulative incidence of new-onset AF. New-onset AF was common after CABG, with most events occurring within the first 30 days, whereas it was rare after PCI, with an even distribution over the 24 months. Undergoing CABG was a significant risk factor for developing new-onset AF. For patients who underwent CABG and developed postoperative AF, the arrhythmia burden was low during the first postoperative year.

Study V was a retrospective cohort study investigating the long-term rhythm out-come of the patients from Study I. At a mean follow-up of 9 years, most patients were in AF. The mean time for freedom from AF after totally endoscopic box lesion ablation for LSPAF was 23 months.