Measuring Ejection Fraction Using Ultrasound

Standard Measurement Technique

The European Society of Cardiology recommends using the biplane method of discs (modified Simpson's rule) obtained from apical four-chamber and two-chamber views to measure ejection fraction, which is particularly reliable in abnormally shaped ventricles 1
The American College of Emergency Physicians suggests using a phased array cardiac transducer (optimal) or a 2-5 MHz curved array abdominal probe with a small footprint if a cardiac probe is unavailable 2
Activate cardiac presets on the machine to optimize image quality, and both portable and cart-based ultrasound machines are acceptable 2

Obtain the apical four-chamber view as the primary view for biplane Simpson's method 1
Obtain the apical two-chamber view as the second view required for biplane Simpson's method 1
The parasternal long-axis view provides complementary information 2
The parasternal short-axis view provides additional assessment of ventricular function 2

Trace the endocardial border at end-diastole (largest cavity size) in both apical four-chamber and two-chamber views 1
Trace the endocardial border at end-systole (smallest cavity size) in the same views 1
The machine calculates volumes using the biplane method of discs (modified Simpson's rule) by integrating segmental areas 1

For rapid bedside assessment, emergency physicians with limited training can accurately estimate EF visually, with normal function being EF > 50% 2
Moderately depressed EF is 30-50% 2
Severely depressed EF is < 30% 2

Three-dimensional measurements are more accurate than 2D when available, particularly validated against cardiac MRI 3
Provides better assessment in patients with good acoustic windows 3
Reduces inter-study variability compared to 2D methods 1

Avoid geometric assumptions, as linear measurements (Teichholz or Quinones methods) are not recommended as they depend on geometric assumptions that fail in abnormally shaped ventricles 1
Harmonic imaging improves reproducibility of 2D LV volumes but uses lower frequencies that may reduce spatial resolution 1
EF varies between imaging modalities and interpreters - a single measurement may not be adequate, particularly for borderline values (41-49%) 4
Load dependency: EF cannot distinguish between preload, afterload, and intrinsic contractility in pressure overload conditions 1
In critically ill patients on ventilatory support, normal EF values are not well established 4
Atrial fibrillation and tachycardia make measurements more challenging - average multiple cardiac cycles 5

When EF appears preserved but dysfunction is suspected, consider global longitudinal strain (GLS), with values < -16% indicating mild depression, and < -10% severe reduction 4
GLS is highly feasible and reproducible, detecting subclinical LV dysfunction before EF impairment 3

Document the indication for the examination, views obtained and image quality, quantitative EF measurement or qualitative assessment, and store images as part of the medical record when feasible 2

A normal left ventricular ejection fraction (LVEF) ranges from 50% to 70%, with a midpoint of 60% according to current American College of Cardiology/American Heart Association guidelines 6
LVEF is classified as follows:
- Hyperdynamic: Greater than 70% 6
- Normal: 50% to 70% 6
- Mildly diminished/reduced: 40% to 49% 6, 7
- Moderately diminished/reduced: 30% to 39% 6, 7
- Severely diminished/reduced: Less than 30% 6, 7

Heart failure is categorized into distinct types based on LVEF, including HFrEF (LVEF ≤40%), HFmrEF (LVEF 41%-49%), and HFpEF (LVEF ≥50%) 8, 9
HFimpEF is defined as previous LVEF ≤40% with follow-up measurement >40% 8

LVEF is calculated as: (EDV-ESV)/EDV × 100, where EDV is end-diastolic volume and ESV is end-systolic volume 10
Quantitative measurement of LVEF is preferred over qualitative assessment 7
The preferred modality for measuring LVEF is: Radionuclide ventriculography, Magnetic resonance imaging (MRI), Echocardiography (2D or 3D), Contrast ventriculography, and Technetium myocardial perfusion imaging 7

LVEF measurement varies between imaging modalities and interpreters 10
A single LVEF measurement at one time point may not be adequate, particularly for values in the mildly reduced range (41-49%) 8

A patient with ST-segment elevation myocardial infarction who was successfully treated with balloon angioplasty and stenting had a normal LVEF of 55% 11
In patients with severe aortic stenosis, preserved ejection fraction is typically defined as ≥50% 12

The American Heart Association recommends that athletes with normal ventricular function (EF ≥50%) can participate in all competitive sports without restriction, as evidenced by a 27-year-old male with an EF of 55% having adequate ventricular function for all activities including competitive athletics 13
No specific cardiac intervention, medication, or activity restriction is warranted based on a normal ejection fraction of 55% in a young adult, according to guidelines from the American College of Cardiology 13

The European Society of Cardiology recommends that the established normal range for LVEF is 53% to 73% (mean 63 ± 5%) using the biplane method of disks, regardless of age, gender, or body size 14, 15
The American College of Cardiology states that normal LVEF is 50-70% with midpoint of 60% 16

2D Echocardiography (Biplane Simpson's) has a normal range of 53-73%, with mean 63 ± 5% 14, 15
3D Echocardiography has a normal range for women of 52-72% with mean LVEF of 62 ± 5% 15

The European Heart Journal suggests that an LVEF of 75% in a 53-year-old woman should be considered normal to mildly hyperdynamic, but requires clinical correlation 14, 15
The American College of Cardiology recommends verifying measurement quality, assessing clinical context, and considering alternative metrics such as global longitudinal strain (GLS) if there is clinical suspicion of dysfunction despite preserved LVEF 17, 18
The European Heart Journal advises documenting ventricular size to ensure the ventricle is not abnormally small 19

The European Heart Journal states that volume status, such as hypovolemia or dehydration, can artificially elevate LVEF 14
The European Heart Journal also notes that a small ventricular cavity may produce artificially high LVEF calculations (>70%) 19
The American Heart Association suggests that compensatory mechanisms, such as early mitral regurgitation or other conditions with reduced afterload, can also contribute to elevated LVEF 17

The European Heart Journal warns against assuming that higher LVEF always means better cardiac function, as LVEF is load-dependent and cannot distinguish between preload, afterload, and intrinsic contractility 14
The European Heart Journal also advises against relying on a single LVEF measurement for clinical decision-making, particularly for borderline values, and recommends serial measurements using the same equipment and methodology 14
The European Society of Cardiology recommends assessing left atrial size and diastolic parameters if heart failure symptoms are present to exclude diastolic dysfunction, which can coexist with preserved or hyperdynamic systolic function 20