Stroke volume

The stroke volume (SV) is referred to as the volume of blood ejected into the aorta or main pulmonary artery during each cardiac cycle. The stroke volume index (SVI) is the stroke volume corrected for the body surface area (BSA).

Usage

The stroke volume is another integral parameter used for the assessment of cardiac function, the calculation of ejection fraction and cardiac output.

Measurement

Echocardiography

Stroke volume may be derived using echocardiography from measurements of the area of the left ventricular outflow tract (LVOT) and the stroke distance. A transthoracic parasternal long axis view allows measurement of the diameter of the left ventricular outflow tract, from which one can determine the cross-sectional area (as one would calculate the area of a circle). An apical 5-chamber view may then be acquired with pulsed wave Doppler interrogation of the left ventricular outflow tract yielding a spectral envelope, the area of which represents the velocity-time integral (VTI) or stroke distance. Stroke volume may then be calculated as follows ⁴:

SV = LVOT area x LVOT VTI [mL]

Alternative anatomical locations which can be interrogated similarly to calculate stroke volume include:

• right ventricular outflow tract (RVOT) area and velocity-time integral (VTI)
  • requires competent aortic and pulmonic valves
• mitral valve annular area and velocity-time integral (VTI)
  • obtained from an apical 4-chamber view in mid-diastole

MRI

The stroke volume is derived from the difference between end-diastolic (EDV) and end-systolic volumes (ESV) as:

SV = EDV – ESV [mL]

The stroke volume index (SVI) can be calculated in the same fashion or calculated from stroke volume as:

SVI = SV/BSA [mL/m²]

Interpretation

Normal values differ for the left and right ventricle depending on gender and age and with the imaging modality used ^1,2:

MRI

Normal values are derived from the publication by Kawel-Boehm with papillary muscles included in ventricular volumes ¹:

Left ventricle

Women (16-83 years):

• SV [mL]:           47-99 mL
• SVI [mL/m²]:   30-59 mL/m²

Men (16-83 years):

• SV [mL]:           55-127 mL
• SVI [mL/m²]:   30-66 mL/m²      

Right ventricle

Women (20-83 years):

• SV [mL]:           39-109 mL
• SVI [mL/m²]:   29-66 mL/m²

Men (20-83 years):

• SV [mL]:           43-146 mL
• SVI [mL/m²]:   28-75 mL/m²

​See also

• end-diastolic volume
• end-systolic volume
• cardiac output and cardiac index
• cardiac MRI
• echocardiography
• cardiac volumes and measurements