The 3S-AF scheme, rather than the 4S-AF scheme, predicts progression in patients with paroxysmal atrial fibrillation: data from RACE V study

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): support from the Netherlands Cardiovascular Research Initiative: an initiative with support of the Dutch Heart Foundation, CVON 2014-9: Reappraisal of Atrial Fibrillation: interaction between hyperCoagulability, Electrical remodelling, and Vascular destabilisation in the progression of AF (RACE V). Purpose To assess whether the 4S-AF scheme predicts AF progression, cardiovascular hospitalizations and mortality in patients with self-terminating paroxysmal AF. Methods We analysed well-phenotyped patients with paroxysmal AF from the Reappraisal of Atrial Fibrillation: Interaction between HyperCoagulability, Electrical remodelling, and Vascular Destabilisation in the Progression of AF (RACE V study). From the 417 patients included in RACE V, 341 (82%) had echocardiography available. Patient had continuous monitoring with implantable loop recorders or pacemakers. Primary endpoint of RACE V was AF progression, defined as (1) progression to persistent or permanent AF, or (2) progression of PAF with >3% burden increase. Median follow-up was 2.2 (1.6-2.8) years. Patients were given a score based on the components of the 4S-AF scheme (St, stroke=1; Sy, symptoms=2; Sb, Severity of burden=2; Su, Substrate=5) to a total maximum of 10 points (table 1). Left atrial fibrosis was not evaluated in our patients and therefore not included into the score. A score of zero (0) in the AF burden domain was given to all patients due to the presence of paroxysmal AF in all. A modified 4S-AF scheme was designed by eliminating the symptom domain, resulting in a 3S-AF scheme. Logistic regression was performed to assess AF progression and the composite endpoint of cardiovascular hospitalizations and mortality, C-statistic to assess prediction of the score, for both using the 4S-AF and the modified 3S-AF scheme. Results Mean age was 65 (IQR 58-71) years, 149 (44%) were women, 103 (48%) had heart failure (HFrEF 6 [2%]; HFpEF 97 [46%]), 276 (81%) had hypertension, 38(11%) had coronary artery disease and 162(48%) atherosclerosis (Table 2, Panel A). Based on the 4S-AF scheme, patients had an average score of 4.5±1.3, the majority had a score under 5 (n=272, 80%), 20% of the score was explained by the S1 domain (stroke), 16% of the score was explained by the Sy domain (symptoms), and 64% of the score was explained by the Su domain (substrate). The score points from the 4S