SMALL heart size is linked to higher mortality risk in individuals with normal ejection fraction , particularly in women and those with high-normal ejection fraction.
This study investigated the relationship between small heart size and mortality in 366,484 adults with normal left ventricular ejection fraction (LVEF ≥50%). Historically, research has focused on the negative outcomes associated with large heart size or reduced ejection fraction, but little attention has been paid to the potential risks of small cardiac volumes. By leveraging the National Echocardiography Database of Australia, this research provides new insights into the clinical implications of small heart size in individuals with preserved or high-normal LVEF.
Using echocardiographic data, participants were categorised into quartiles based on left ventricular end-diastolic volume (LVEDV) and LVEDV indexed to body surface area (LVEDVi). Over 2 million person-years of follow-up, 65,241 deaths were recorded. Smaller LVEDVi was consistently linked to higher all-cause mortality, with individuals in the lowest quartile showing 14–18% greater odds of death over five years compared to those with larger hearts. The effect was particularly pronounced in individuals with high-normal LVEF (≥60%) and in women, who experienced a 30% increased risk of cardiovascular mortality in the lowest quartile. Men, however, showed no significant association between small heart size and cardiovascular mortality. A U-shaped relationship emerged between LV chamber size and all-cause mortality, suggesting that both extremely small and large hearts may pose risks.
These findings challenge the conventional focus on larger cardiac volumes and highlight the need for increased awareness of the potential risks associated with small heart size in clinical practice. For women and those with high-normal LVEF, small cardiac size may reflect an underlying pathophysiological phenotype requiring closer monitoring and tailored management. Future research should aim to elucidate the mechanisms driving these associations and explore interventions to improve outcomes for this subset of patients. Clinicians should remain alert to the implications of small cardiac size in patients with normal ejection fraction, integrating these insights into personalised treatment strategies.
Katrina Thornber, EMJ
Reference
Rowe SJ et al. Small heart size and premature death in 366,484 individuals with normal ejection fraction. JACC Adv. 2025;4(1):101444.
