What does LVEDF (Left Ventricular Ejection Fraction) mean in circulation studies?

LVEF (Left Ventricular Ejection Fraction) in Circulation Studies

LVEF in circulation studies refers to Left Ventricular Ejection Fraction, which is the percentage of blood ejected from the left ventricle during contraction of the heart, calculated as ([EDV-ESV]/EDV) × 100, where EDV is end-diastolic volume and ESV is end-systolic volume. 1, 2

Definition and Calculation

• LVEF is defined as the proportion of blood ejected during left ventricular contraction of the heart, expressed as a percentage 1
• The formula for calculating LVEF is: LVEF = ([EDV-ESV]/EDV) × 100 1, 2
  • EDV (End-Diastolic Volume): Volume of blood in the left ventricle at the end of ventricular filling 2
  • ESV (End-Systolic Volume): Volume of blood remaining in the left ventricle at the end of ventricular ejection 2

Classification of LVEF Values

• Normal: 50% to 70% (left ventricular systolic function is normal) 3, 2
• Hyperdynamic: Greater than 70% (greater than normal proportion of blood is ejected during systole) 1, 3
• Mildly reduced: 40% to 49% (slightly reduced proportion of blood ejected compared to normal) 1, 3
• Moderately reduced: 30% to 39% (moderately smaller proportion of blood ejected than normal) 1, 3
• Severely reduced: Less than 30% (considerably less proportion of blood ejected than normal) 1, 3

Measurement Methods

• Quantitative measurement of LVEF is preferred over qualitative assessment 1
• LVEF can be measured using various imaging modalities, with a preferred hierarchy of 1:
  • Radionuclide ventriculography
  • Magnetic resonance imaging (MRI)
  • Echocardiography (2D or 3D)
  • Contrast ventriculography
  • Technetium myocardial perfusion imaging

Clinical Significance

• LVEF is a key parameter in diagnosing and classifying heart failure 3, 4:

  • HFrEF (Heart Failure with reduced EF): LVEF ≤40%
  • HFmrEF (Heart Failure with mid-range EF): LVEF 41%-49%
  • HFpEF (Heart Failure with preserved EF): LVEF ≥50%
  • HFimpEF (Heart Failure with improved EF): Previous LVEF ≤40% with follow-up measurement >40%

• LVEF is a strong predictor of clinical outcomes in cardiovascular disease 5:

  • Low normal LVEF (50-55%) is associated with a 3.64 times higher risk of developing heart failure compared to normal LVEF (≥55%)
  • LVEF <50% is associated with a 9.52 times higher risk of developing heart failure

Important Considerations and Limitations

• LVEF measurement varies between imaging modalities and interpreters 3, 2
• A single LVEF measurement at one time point may not be adequate, particularly for values in the mildly reduced range (41-49%) 3
• LVEF ≤55% may be a significant cutoff point for predicting future progression from preserved to mildly reduced ejection fraction 6
• Newer parameters like first-phase ejection fraction (LVEF-1) may provide earlier detection of cardiac dysfunction even when standard LVEF appears normal 7