Small left ventricle identifies a high-risk phenotype in patients hospitalized for heart failure with preserved or mildly reduced ejection fraction.

In heart failure with mildly reduced (HFmrEF) or preserved ejection fraction (HFpEF), a smaller left ventricular end-diastolic diameter (LVEDD) has been associated with lower stroke volume and functional capacity. However, its association with clinical outcomes remains unexplored. We evaluated the prognostic impact of small LV in patients hospitalized with acute HFpEF. We performed a single-center retrospective analysis of a prospectively collected cohort of patients admitted for acute heart failure (AHF) with LVEF >40%. Small LV was defined according to ASE guidelines. The primary outcome was in-hospital mortality; secondary outcomes included worsening renal function and need for inodilators. Among 369 patients, 82 (22.2%) had a small LV. These patients had fewer traditional comorbidities but more amyloid cardiomyopathy and lower systolic blood pressure. In-hospital mortality was significantly higher in the small LV group (12.2% vs 3.5%, p = 0.002). In multivariable analysis, small LV was independently associated with mortality (adjusted OR 7.15). These findings suggest that in HFpEF or HFmrEF, small LV represents a high-risk phenotype.