Stroke volume

The stroke volume , specifically, the stroke volume (English stroke volume , SV abbreviation) is a technical term of the physiology . It is used to describe the volume of blood that is ejected from the left ventricle when the heart beats . The stroke volume is the quotient of the heart work and the mean arterial blood pressure . The cardiac output is the product of cardiac work and heart rate and also the product of cardiac output and blood pressure. The stroke work is the product of stroke volume and blood pressure.

Calculation and measurement

Determination of stroke volume
in echocardiography

The stroke volume can be estimated and calculated from the impedance cardiography , the echocardiography or the cardiac catheter examination . The stroke volume can also be calculated using cardiac CT ( computed tomography ), cardiac MRI ( magnetic resonance imaging ) or myocardial scintigraphy .

The stroke volume is usually calculated as the difference between the (left ventricular) end diastolic and end systolic volume (EDV and ESV):

${\displaystyle SV=EDV-ESV}$

Two other important functional parameters of the heart can be derived from the stroke volume:

• the ejection fraction as the ratio of stroke volume to end-diastolic volume:

${\displaystyle EF={\frac {SV}{EDV}}=1-{\frac {ESV}{EDV}}={\frac {EDV-ESV}{EDV}}}$

• the cardiac output as the product of stroke volume and heart rate :

${\displaystyle {\begin{aligned}HZV&=SV\cdot HF\\&=EDV\cdot EF\cdot HF\end{aligned}}}$

The stroke volume in relation to the body surface is called the stroke index (SI) , analogous to the heart index .

Normal value and lowered values

The normal value of the stroke volume in both chambers is around 70 to 100  ml . The stroke volumes of the right and left ventricles are essentially the same. The ejection fraction averages 0.6 to 0.7.

A decreased stroke volume is often found in heart attacks , heart muscle and heart valve diseases .

physiology

A distinction must be made between the gross blow volume and the net blow volume. Their difference is called the pendulum volume or regurgitation volume . The causes are heart valve defects or septal defects . With each heartbeat, all four stroke volumes of the four heart cavities are different. The enddistolic cavity volumes and the associated net ejection fractions are also always different for each heartbeat; only your product must be identical. This product is the net beat volume of each heart cavity.

See also

• pump
• Frank Starling Mechanism
• physiology
• Inotropy
• Heart failure
• peripheral resistance

literature

• Reinhard Larsen: Anesthesia and intensive medicine in cardiac, thoracic and vascular surgery. (1st edition 1986) 5th edition. Springer, Berlin / Heidelberg / New York et al. 1999, ISBN 3-540-65024-5 , p. 217 f.
• Wolfgang Trautwein , Otto Heinrich Gauer , Hans-Peter Koepchen : Heart and Circulation , Urban & Schwarzenberg , Munich, Berlin, Vienna 1972, ISBN 3-541-05411-5 .

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !

Individual evidence

1. ^ Walter Bleifeld, Christian Wilhelm Hamm : Heart and Circulation , Springer-Verlag, Berlin, Heidelberg, New York 1987, ISBN 3-540-17931-3 , ISBN 0-387-17931-3 , p. 23.