Ejection Fraction and Contractility: Key Distinctions and Clinical Implications

Introduction to Ejection Fraction and Contractility

The European Society of Cardiology notes that ejection fraction (EF) is not an index of contractility, as it is a load-dependent parameter reflecting preload, afterload, heart rate, valvular function, and ventricular volumes 1
EF represents stroke volume divided by end-diastolic volume, making it a volumetric ratio rather than a measure of intrinsic muscle function 1
The American Heart Association indicates that contractility refers to the intrinsic ability of myocardial muscle to generate force, independent of loading conditions 3, 4

In patients with aortic stenosis and concentric hypertrophy, EF may remain normal or elevated despite depressed intrinsic contractility, as noted by the American College of Cardiology 3, 4
In heart failure with preserved ejection fraction (HFpEF), EF is preserved, but intrinsic myocardial function may be impaired, as evidenced by reduced global longitudinal strain (GLS), according to the European Society of Cardiology 5
The European Society of Cardiology recommends considering the clinical context, including loading conditions, valvular function, and chamber geometry, when interpreting EF 1

The American Heart Association states that the inverse relationship between systolic wall stress and EF is maintained, as long as wall stress is normal, EF is preserved regardless of underlying contractility 3, 4
Preload manipulation dramatically affects EF, and ventricular dilation in heart failure with reduced ejection fraction (HFrEF) may maintain stroke volume despite severely reduced contractility, as noted by the European Heart Journal 1

Load-independent contractility measures, such as end-systolic elastance (Ees) and preload recruitable stroke work (PRSW), have incremental prognostic value over EF, according to the American College of Cardiology 3, 4
Global longitudinal strain (GLS) detects subclinical myocardial dysfunction even when EF is preserved, particularly in HFpEF, as recommended by the European Society of Cardiology 5

The American College of Cardiology recommends always interpreting EF in clinical context, considering loading conditions, valvular function, and chamber geometry 1
When EF is reduced, determine if this reflects true contractile dysfunction or excessive afterload/inadequate compensation, as suggested by the American Heart Association 3, 4
The European Society of Cardiology advises against equating preserved EF with preserved contractility, particularly in HFpEF, concentric hypertrophy, or valvular disease 1, 5