Abstract 15080: Higher Mortality Risk in Very Severe Aortic Stenosis Associated With Atrial Fibrillation

Background: Atrial fibrillation (AF) in severe aortic stenosis (AS) is associated with worse outcomes compared to sinus rhythm (SR). The prevalence of AF and its impact on outcomes in very severe AS (vsAS) is unknown. Objectives: To determine the prevalence and prognostic significance of AF in vsAS. Methods: A total of 563 patients with vsAS (transaortic valve peak velocity ≥5 m/sec) were identified retrospectively out of 3139 with aortic valve area ≤1.0 cm 2 or ≤0.6 cm 2 /m 2 and left ventricular ejection fraction (LVEF) ≥50%. Patients were divided by rhythm (AF vs SR) at the time of index transthoracic echocardiogram. Outcomes in AF versus SR were compared in propensity-matched analyses (2 SR:1 AF). Results: AF was present in 50/563 patients (9%) and SR in 513/563 (91%). In propensity-matched analyses (100 SR:50 AF), the mean age was 83.2±7.3 years, 54% were female. There was no difference in comorbidity index (p=0.84). There was no difference in AF compared to SR in aortic valve area (0.7±0.1 vs 0.7±0.1 cm 2 , p=0.94), peak velocity (5.3±0.3 vs 5.3±0.3 m/sec, p=0.32), LVEF (63±7 vs 65±7%, p=0.14) or E/e’ (23±13 vs 21±12, p=0.48), but patients with AF had larger left atrial volume index (60±16 vs 48±15 mL/m 2 , p<0.001), higher right ventricular systolic pressure (52±15 vs 41±16 mmHg, p<0.001), and higher prevalence of moderate or more tricuspid regurgitation (33% vs 5%, p<0.001) and right ventricular systolic dysfunction (23% vs 6%, p=0.003). Age-, sex-, comorbidity index-adjusted all-cause mortality was higher in AF vs SR (HR 2.33 [1.40, 3.87], p=0.001) ( Figure: Observed overall survival ). Aortic valve replacement (AVR) was associated with improved survival (HR 0.44 [0.25, 0.76], p=0.004) with no evidence of interaction of AVR and rhythm (p=0.15). Conclusion: AF was not uncommon among patients with vsAS and identified a subset of patients with vsAS at much higher risk of mortality. Whether AVR should be considered earlier in vsAS when associated with AF needs to be investigated.