Ejection Fraction Calculator

Variables and formula

The above calculator determines ejection fraction in percentage based on stroke volume and end diastolic volume. EF is defined as the outbound blood pumped during each heartbeat and is obtained via:

EF (%) = SV / EDV x 100

Stroke volume (the amount of blood pumped by the heart in one minute) can be obtained by:

1) EDV – ESV (when end systolic volume is known)

2) Cardiac output in mL/min / Heart rate in bpm

Normal end diastolic volume for the left ventricle (systemic circulation) is between 121 mL and 163 mL.

About ejection fraction

EF is a measure of cardiac function and, being dependent on the condition of the myocardial muscle and of the arteries, indicates the severity of systolic heart failure.

During an echocardiogram, the volumes of heart chambers and their modification across the cardiac cycle are recorded and measured, including the EF. Sound waves produce images of the blood pumping function.

Cardiovascular magnetic resonance imaging creates a magnetic field and radio waves to visualize cross sectional images of the heart.

Computerized tomography (CT) uses x-rays to create cross sectional images while during a nuclear medicine scan radioactive material is injected in the bloodstream to detect blood flow.

Normal EFs are between 50 and 65%.

In athletes and individuals in great physical condition, EF can reach up to 90% during exercise because of the high increase in stroke volume. Increased vascular resistance or sympathetic stimulation also increase EF.

EF tends to decrease below 40% in these conditions:

■ Systolic congestive heart failure;

■ Myocardial damage caused by MI;

■ Dilated cardiomyopathy;

■ Atrial fibrillation;

■ Persistent hypertension.

References

1. Wandt B, Bojo L, Tolagen K, Wranne B. Echocardiographic assessment of ejection fraction in left ventricular hypertrophy. Heart. 1999; 82(2): 192–198.

2. Feng B, Sitek A, Gullberg GT. Calculation of the left ventricular ejection fraction without edge detection: application to small hearts. J Nucl Med. 2002; 43(6):786-94.

3. Wisneski JA, Pfeil CN, Wyse DG, Mitchell R, Rahimtoola SH, Gertz EW. Left ventricular ejection fraction calculated from volumes and areas: underestimation by area method. Circulation. 1981; 63(1):149-51.