Prognostic impact of the HFA-PEFF and H2FPEF scores in patients with sick sinus syndrome

Background Sick sinus syndrome (SSS) frequently coexists with atrial fibrillation (AF) and may represent a clinical manifestation of atrial cardiomyopathy (AtCM). Many patients with AtCM have preserved left ventricular ejection fraction (LVEF), and heart failure with preserved ejection fraction (HFpEF) commonly overlaps with AF. The HFA-PEFF and H2FPEF scores were developed to aid HFpEF diagnosis and have shown prognostic relevance in various settings. However, their utility in patients with SSS following pacemaker implantation remains unclear. We investigated whether these scores predict cardiovascular outcomes and AF progression in this population. Methods In this multicenter observational study, 206 patients with SSS and LVEF ≥50% who underwent dual-chamber pacemaker implantation between 2020 and 2021 were included. Patients with persistent AF, prior AF ablation, structural cardiomyopathy, or conduction system pacing were excluded. HFA-PEFF and H2FPEF scores were calculated using echocardiographic and clinical parameters obtained two days after implantation. The primary endpoint was a composite of heart failure hospitalization, ischemic stroke, or cardiovascular death. The secondary endpoint was new-onset persistent AF (≥7 days), detected by continuous device monitoring. Results Median age was 81 (IQR 75–85) years; 49.5% were female, and 54.9% had prior paroxysmal AF. According to HFA-PEFF classification, 45.6% were categorized as high probability (score 5–6). Over a median follow-up of 36 months, 35 patients experienced the primary endpoint and 45 developed persistent AF. Higher HFA-PEFF scores were independently associated with the primary endpoint (adjusted HR 1.44, 95% CI 1.03–2.02, p=0.031), whereas H2FPEF was not. The AUC for predicting the primary endpoint was 0.70 for HFA-PEFF and 0.61 for H2FPEF. Similarly, higher HFA-PEFF scores independently predicted new-onset persistent AF (adjusted HR 1.44, 95% CI 1.09–1.90, p=0.011), while H2FPEF showed no independent association. The AUC for persistent AF was 0.69 for HFA-PEFF and 0.65 for H2FPEF. Conclusions In patients with SSS and preserved LVEF after pacemaker implantation, the HFA-PEFF score—but not the H2FPEF score—independently predicted cardiovascular events and AF progression. These findings suggest that structural and functional markers of diastolic dysfunction and atrial remodeling captured by the HFA-PEFF score may reflect the underlying AtCM phenotype in SSS. The HFA-PEFF score may serve as a practical tool for risk stratification in this high-risk population.