Atrial fibrillation (AF) results in the loss of atrial booster pump function and portends poorer outcome in aortic valve stenosis (AS). However, its characteristics and impact on medically managed AS remained under-recognised. We compared these patients with AF to sinus rhythm (SR).

In total, 347 consecutive patients with medically managed severe AS (aortic valve area <1 cm²) and preserved left ventricular ejection fraction (>50%) were studied, in terms of echocardiographic characteristics and clinical outcomes. Appropriate univariate and multivariate models were used, while Kaplan–Meier curves and Cox regression models were constructed to compare clinical outcomes (mortality, admissions for congestive cardiac failure, and stroke).

Ninety (90) (25.9%) patients had AF. Patients with AF had lower body mass index (BMI 18.5±10.4 vs 23.8±6.2 g/m²; p<0.001), larger left ventricular mass index (LVMI 127.9±39.0 vs 116.7±36.5; p=0.017), and left atrial volume index (53.2±20.0 vs 31.0±9.2 mL/m²; p=0.004). Atrial fibrillation was associated with higher mortality (52.2% vs 37.4%; Kaplan-Meier log-rank 7.18; p=0.007), admissions for congestive cardiac failure (log-rank 6.42; p=0.011), and poorer composite outcomes (log-rank 6.29; p=0.012). The incidence of stroke in both groups were similar on follow-up (log-rank 0.08; p=0.776). After adjusting for age, BMI, LVMI, and left atrial volume index on Cox regression, AF remained independently associated with poorer composite clinical outcomes (hazard ratio, 1.66; 95% confidence interval 1.07–2.58).

Atrial fibrillation remained an important comorbidity affecting a quarter of patients with medically managed severe AS. It was independently associated with poorer clinical outcomes and may thus aid in prognostication and management.