What is the clinical evidence from this study?

Study design: Cohort. Population: Decompensated heart failure (n=2331). Intervention: Heart failure with preserved ejection fraction (HFpEF) vs. Heart failure with reduced ejection fraction (HFrEF). Primary outcome: Sudden cardiac death (SCD) (p=<0.01).

October 23, 2025Scientific Reports1 citationsOpen Access

Distinct mortality patterns and sudden cardiac death mechanisms in heart failure with a preserved ejection fraction

Q: What are the key findings of this study?

Patients with HFpEF had a significantly lower incidence of sudden cardiac death (5.9%) compared to those with HFrEF (16.7%) and HFmrEF (13.8%), with asystole being the predominant mechanism.

YSYoshihiro SobueFujita Health University Hospital EWEiichi WatanabeUniversity of North Carolina at Charlotte MYMasanobu YanaseFujita Health University

Key Result

Patients with HFpEF had a significantly lower incidence of sudden cardiac death (5.9%) compared to those with HFrEF (16.7%) and HFmrEF (13.8%), with asystole being the predominant mechanism.

Study Design

Type

Cohort (n=2,331)

Multicenter

Structured PICO

Population

2,331 consecutive patients hospitalized for decompensated heart failure (stratified into HFpEF n=754, HFmrEF n=369, HFrEF n=1208), mean age 74, 57% male, based in Japan. Key exclusions: in-hospital death, NYHA class IV at discharge, newly diagnosed HF within 3 months, acute coronary syndrome within 40 days, recent coronary revascularization within 90 days, prior implantation of an ICD or CRT-D for secondary prevention, end-stage kidney disease requiring dialysis, hypertrophic cardiomyopathy, or cardiac amyloidosis.

Outcome

Sudden cardiac death (SCD), defined as an unexpected, non-traumatic fatal event occurring within 24 h of symptom onset (including documented VT/VF or appropriate ICD therapy) over a median 25-month follow-up.hard clinical

In patients with HFpEF, sudden cardiac death is less frequent than in HFrEF and is predominantly caused by asystole, with NYHA class III and prolonged QTc interval serving as independent predictors.

Main Result

Absolute Event Rate: 5.9% vs 16.7%

p-value: p=<0.01

Limitations

Single center study limiting generalizability
Low autopsy rates (4.0%) affecting accuracy of SCD classification
Uncertainty about preceding arrhythmias for cases categorized as asystole upon hospital arrival
Echocardiographic assessments only performed at discharge
Small number of SCD events in HFpEF patients (n=45) limiting statistical power
Unable to assess impact of ARNI and SGLT2 inhibitors
No data on non-sustained VT

Abstract

Sudden cardiac death (SCD) is a leading cause of mortality in heart failure (HF), yet its incidence, mechanisms, and predictors in heart failure with preserved ejection fraction (HFpEF) remain poorly characterized. We conducted a prospective study of 2331 patients hospitalized for decompensated HF, stratifying them into HFpEF (n = 754), HF with mid-range ejection fraction (HFmrEF, n = 369), and HF with reduced ejection fraction (HFrEF, n = 1208). Over a median 25-month follow-up, 298 patients (12.8%) experienced SCD. HFpEF patients had the lowest SCD incidence (5.9%) compared to HFmrEF (13.8%) and HFrEF (16.7%) (p 480 ms (csHR 1.63, 95% CI 1.03-2.55, p = 0.01; sHR 1.57, 95% CI 1.04-2.38, p = 0.03) independently predicted SCD in patients with HFpEF. These findings reveal distinct SCD patterns in HFpEF and underscore the need for phenotype-specific risk stratification and prevention strategies.

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