Po-02-192 new onset, recurrence and progression of atrial fibrillation after cardiac surgery during 2.5 years of continuous rhythm monitoring

Atrial fibrillation (AF) in the early postoperative phase (POAF) is a frequent complication after cardiac surgery which is also associated with late AF-recurrences. However, it is unknown how POAF-burden (percentage of time in AF) progresses in the time following surgery. Recent studies suggested that AF-burden is associated with increased risk of stroke and therefore identifying factors associated with a higher POAF-burden is desirable. To investigate POAF-burden progression patterns and factors associated with increased POAF-burden after cardiac surgery during 2.5 years of continuous rhythm monitoring. Patients with and without history of AF undergoing cardiac surgery were included. Preoperatively, all patients underwent transthoracic echocardiography, electrocardiography, and blood biomarker analysis. Continuous rhythm monitoring was performed over a period of 2.5 years with an implantable loop recorder. POAF-burden progression was calculated as percentage of time in AF for different time intervals (0-3, 3-12, and 12-30 months). Classification of burden was performed based on the cut-off values for tertiles. In addition, AF-characteristics such as episode duration and ventricular rate were analyzed as potential surrogate markers of POAF-burden. The study population consisted of 98 patients which completed 2.5 years of rhythm FU. Highest POAF-burden was observed in the first 3 postoperative months with a significant reduction between 3-12 moths (p=0.007) (Figure 1). In the period between 12-30 months an increase in POAF burden was observed for all groups (p<0.001), however the burden remained lower as compared to the first 3 postoperative months (Figure 1). Univariable differences between patients with and without progression of POAF-burden are shown in Table 1. Multivariable analysis showed no independent predictors of POAF-burden progression. Individual postoperative POAF-burden was strongly associated with the longest POAF-episode (Spearman’s rho=0.86, 95%CI: 0.75-0.92, p<0.001), and to a lower extent with the duration of the median episode (Spearman’s rho=0.38, 95%CI: 0.13-0.58, p=0.001). Patients developing POAF have the highest POAF-burden in the first 3 postoperative months. Increased atrial volumes and reduced atrial ejection fraction seem to be associated with AF-burden progression. Also, AF-burden seems to be highly correlated to the longest individual episode duration.