Stroke Volume Calculator

Stroke Volume equals End Diastolic Volume minus End Systolic Volume

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What Is Stroke Volume?

Stroke volume (SV) is the volume of blood ejected from the left ventricle with each heartbeat. It is calculated as the difference between the end-diastolic volume (the volume of blood in the ventricle at the end of filling) and the end-systolic volume (the volume remaining after contraction). A typical resting stroke volume for a healthy adult is 60 to 80 mL.

Worked Example

An echocardiogram reports an end-diastolic volume (EDV) of 120 mL and an end-systolic volume (ESV) of 50 mL for a patient. Using the formula SV = EDV - ESV, the stroke volume is 120 - 50 = 70 mL. The ejection fraction is (70 / 120) × 100 = 58.3%, which is within the normal range of 55–70%.

Ejection Fraction

The ejection fraction (EF) represents the percentage of blood ejected from the left ventricle with each contraction: EF = (SV / EDV) × 100. A normal EF is typically 55\u201370%. Values below 40% indicate systolic heart failure (HFrEF), while preserved ejection fraction heart failure (HFpEF) involves an EF above 50% but with diastolic dysfunction. This calculator automatically computes EF when all three volumes are known.

Frequently Asked Questions

How is stroke volume measured?

Echocardiography is the primary noninvasive method for measuring stroke volume. The Simpson biplane method estimates ventricular volumes by tracing the endocardial border at end-diastole and end-systole. Doppler echocardiography can also calculate SV from the left ventricular outflow tract diameter and velocity-time integral.

What factors affect stroke volume?

Three main factors govern SV: preload (Frank-Starling mechanism), afterload (aortic resistance), and contractility (myocardial force generation). Increasing preload or contractility raises SV, while increased afterload tends to decrease it.

What is a normal end-diastolic volume?

Normal left ventricular end-diastolic volume is approximately 110\u2013120 mL in adult males and 90\u2013100 mL in adult females. Values above these ranges may indicate volume overload or dilated cardiomyopathy.

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