Stroke Volume Calculator
Calculate your stroke volume using End Diastolic Volume (EDV) and End Systolic Volume (ESV).
Your Stroke Volume:
— mLUnderstanding Stroke Volume and How to Calculate It
Stroke Volume (SV) is a fundamental measurement in cardiology that represents the volume of blood ejected from the left ventricle (or the right ventricle) of the heart during one contraction (heartbeat). It is a critical determinant of cardiac output, which is the total volume of blood pumped by the heart per minute.
A healthy stroke volume indicates efficient heart function. Deviations from the normal range can be indicative of various cardiovascular conditions, such as heart failure, hypertrophic cardiomyopathy, or aortic valve stenosis.
The Calculation Formula
The calculation of stroke volume is straightforward, provided you have the values for End Diastolic Volume (EDV) and End Systolic Volume (ESV).
The formula is:
Stroke Volume (SV) = End Diastolic Volume (EDV) – End Systolic Volume (ESV)
- End Diastolic Volume (EDV): This is the maximum volume of blood in the ventricle at the end of diastole (when the ventricle is fully relaxed and filled with blood). It's the volume the ventricle holds before it contracts.
- End Systolic Volume (ESV): This is the minimum volume of blood remaining in the ventricle at the end of systole (when the ventricle has contracted). It's the volume left in the ventricle after it has ejected blood.
The difference between the volume at its fullest (EDV) and the volume left after contraction (ESV) gives you the precise amount of blood that was pumped out during that single beat. The standard unit for stroke volume is milliliters (mL).
Why is Stroke Volume Important?
- Cardiac Output Determination: SV is a key component of cardiac output (CO). CO = SV x Heart Rate. Understanding SV helps in assessing how much blood the heart is pumping to the body.
- Heart Health Assessment: Changes in SV can signal underlying heart problems. A decreased SV might suggest the heart is not contracting effectively, which is common in heart failure. An abnormally high SV could also indicate certain conditions.
- Treatment Monitoring: For patients with cardiovascular diseases, monitoring changes in SV can help doctors evaluate the effectiveness of medications or other treatments.
- Exercise Physiology: During exercise, both heart rate and stroke volume typically increase to meet the body's higher demand for oxygen. Understanding SV helps analyze the body's cardiovascular response to physical activity.
How to Obtain EDV and ESV
EDV and ESV are typically measured using non-invasive cardiac imaging techniques such as:
- Echocardiography (Ultrasound of the heart): This is the most common method. It uses sound waves to create images of the heart, allowing measurements of chamber dimensions and blood volume at different points in the cardiac cycle.
- Cardiac Magnetic Resonance Imaging (CMR): Provides highly detailed images of the heart and can accurately quantify blood volumes.
- Other methods: Less commonly, techniques like cardiac catheterization (invasive) or impedance cardiography might be used.
These values are usually determined by trained medical professionals in a clinical setting.
Example Calculation
Let's consider a patient whose echocardiogram reveals the following:
- End Diastolic Volume (EDV) = 130 mL
- End Systolic Volume (ESV) = 45 mL
Using the formula:
SV = 130 mL – 45 mL = 85 mL
Therefore, the stroke volume for this individual is 85 mL. This value falls within the typical healthy range for adults at rest.