Stroke volume

Stroke volume (SV) is the volume of blood pumped from the left ventricle per beat. It is measured in milliliters (ml) and varies depending on various factors such as heart rate, contractility, and blood pressure. Stroke volume is a crucial component of cardiac output, which is the total volume of blood pumped by the heart per minute.

Calculation[edit | edit source]

Stroke volume is calculated using the formula: SV = EDV - ESV. Where:

EDV (End Diastolic Volume) is the total volume of blood in the ventricle immediately before a contraction (systole).
ESV (End Systolic Volume) is the volume of blood left in the ventricle after contraction.

Factors affecting stroke volume[edit | edit source]

Several factors can affect stroke volume, including:

Preload: The initial stretching of the cardiac myocytes prior to contraction. It is related to ventricular filling.
Afterload: The pressure that the heart must work against to eject blood during systole.
Contractility: The inherent vigor of contraction of the heart muscles, independent of preload.

Clinical significance[edit | edit source]

Stroke volume is an important indicator of cardiac health. Abnormal stroke volume can be a sign of several heart conditions, including heart failure, cardiomyopathy, and valvular heart disease. It is also a critical parameter in the management of shock and sepsis.