Impact of stroke volume on prognostic outcome in patients with atrial fibrillation and concomitant heart failure with preserved ejection fraction

Background Atrial fibrillation (AF) can lead to a decrease in stroke volume (SV) despite a preserved left ventricular ejection fraction (LVEF). However, no previous studies have evaluated the prognostic importance of the decreased SV in patients with AF and concomitant heart failure with preserved ejection fraction (HFpEF). Methods We retrospectively studied the cases of 1520 consecutive patients who had undergone right heart catheterization. HFpEF (New York Heart Association functional class ≥II and LVEF ≥50%) was observed in 574 patients. We selected 47 patients with persistent AF with a heart rate of 40–110 bpm and HFpEF without other underlying heart diseases. Results Among a total of 47 patients, 16 (34%) had normal SV [SV index (SVI) >35 ml/m2 and 31 (66%) patients had low SV (SVI ≤ 35 ml/m2)]. During the follow-up period of 1115 ± 305 days, 14 patients (30%) met the composite endpoint defined as cardiac death and admission due to worsening heart failure. Cox proportional hazard ratio analysis showed that SVI was a predictor of the endpoint, independently of the cardiac index and other parameters. Kaplan–Meyer analysis showed that low SVI was significantly associated with a poor prognosis, with an event-free rate of 58% at the mean follow-up period of 991 days (log-rank p = 0.02). In the multiple regression analysis, a high systemic vascular resistance index and a high heart rate were independent determinants of low SVI. Conclusions Our findings suggest that low SV had a significant impact on prognosis in patients with AF despite the preserved LVEF. The SVI depended on the heart rate and SVRI.