Left ventricular ejection fraction: clinical, pathophysiological, and technical limitations

Area of Science:

• Cardiology
• Echocardiography
• Cardiovascular Physiology

Background:

• Left ventricular ejection fraction (LVEF) is a cornerstone in cardiovascular guidelines for risk stratification and treatment decisions in heart failure (HF).
• Current guidelines rely heavily on LVEF for critical choices like valve replacement timing and implantable cardioverter-defibrillator selection.
• However, LVEF is a global measure affected by loading conditions, geometry, and image quality, leading to significant variability.

Purpose of the Study:

• To critically analyze the clinical, pathophysiological, and technical limitations of LVEF in cardiovascular disease.
• To highlight how LVEF may not accurately reflect myocardial contractile function despite its widespread use.
• To discuss the implications of LVEF variability and limitations in guiding patient management.

Main Methods:

• This review synthesizes existing literature on LVEF.
• It examines the pathophysiological basis of LVEF measurement and its determinants.
• Clinical and technical factors influencing LVEF accuracy are analyzed.

Main Results:

• LVEF reflects global cavity volume changes, not direct myocardial contractility, and can be normal even with impaired myofibril function.
• Subtle myocardial ischemia may be masked by compensatory mechanisms of other myocardial fiber layers, preserving LVEF.
• The dynamic nature of heart failure and interventional outcomes can alter LVEF, impacting its reliability for treatment guidance.

Conclusions:

• LVEF possesses inherent limitations that challenge its role as a sole determinant for critical cardiovascular decisions.
• Understanding these limitations is crucial for accurate patient assessment and effective therapeutic strategies in cardiovascular pathologies.
• Alternative or complementary methods may be needed to better assess systolic function and guide management in complex cardiovascular conditions.