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In cardiovascular physiology, stroke volume (SV) is the volume of blood pumped from the ventricle per beat. Stroke volume is calculated using measurements of ventricle volumes from an echocardiogram and subtracting the volume of the blood in the ventricle at the end of a beat (called end-systolic volume [note 1]) from the volume of blood just prior to the beat (called end-diastolic volume).
Major factors influencing cardiac output – heart rate and stroke volume, both of which are variable. [1]In cardiac physiology, cardiac output (CO), also known as heart output and often denoted by the symbols , ˙, or ˙, [2] is the volumetric flow rate of the heart's pumping output: that is, the volume of blood being pumped by a single ventricle of the heart, per unit time (usually measured ...
Ventricular stroke work (SW) is defined as the work performed by the left or right ventricle to eject the stroke volume into the aorta or pulmonary artery, respectively. The area enclosed by the PV loop is a measure of the ventricular stroke work, which is a product of the stroke volume and the mean aortic or pulmonary artery pressure ...
A blood volume increase would cause a shift along the line to the right, which increases left ventricular end diastolic volume (x axis), and therefore also increases stroke volume (y axis). The Frank–Starling law of the heart (also known as Starling's law and the Frank–Starling mechanism ) represents the relationship between stroke volume ...
The difference between EDV and ESV is the stroke volume (SV). The ejection fraction is the fraction of the end-diastolic volume that is ejected with each beat; that is, it is stroke volume (SV) divided by end-diastolic volume (EDV): [23] (%) = Where the stroke volume is given by:
End-systolic volume (ESV) is the volume of blood in a ventricle at the end of contraction, or systole, and the beginning of filling, or diastole. ESV is the lowest volume of blood in the ventricle at any point in the cardiac cycle. The main factors that affect the end-systolic volume are afterload and the contractility of the heart.
The flow through the LVOT, or LV stroke volume (in cm 3), can be calculated by measuring the LVOT diameter (in cm), squaring that value, multiplying the value by 0.78540 (which is π/4) giving a cross sectional area of the LVOT (in cm 2) and multiplying that value by the LVOT VTI (in cm), measured on the spectral Doppler display using pulsed ...
Afterload is a determinant of stroke volume (in addition to preload, and strength of myocardial contraction). [ 1 ] Following Laplace's law , the tension upon the muscle fibers in the heart wall is the pressure within the ventricle multiplied by the volume within the ventricle divided by the wall thickness (this ratio is the other factor in ...