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A Wiggers diagram, named after its developer, Carl Wiggers, is a unique diagram that has been used in teaching cardiac physiology for more than a century. [1] [2] In the Wiggers diagram, the X-axis is used to plot time subdivided into the cardiac phases, while the Y-axis typically contains the following on a single grid: Blood pressure. Aortic ...
[2] In practice, a-vO 2 diff may be determined using the Fick Principle rather than by taking direct blood samples. In order to do so oxygen consumption (VO 2) may be measured using a spirometer to detect gaseous concentrations in exhaled air compared to inhaled air, while cardiac output can be determined using a Doppler ultrasound. [3]
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 ...
Modalities applied to measurement of ejection fraction is an emerging field of medical mathematics and subsequent computational applications. The first common measurement method is echocardiography, [7] [8] although cardiac magnetic resonance imaging (MRI), [8] [9] cardiac computed tomography, [8] [9] ventriculography and nuclear medicine (gated SPECT and radionuclide angiography) [8] [10 ...
Therefore, using the assumed Fick determination, the approximated cardiac output for an average man (1.9 m3) is: Cardiac Output = (125 mL O 2 /minute × 1.9) / (200 mL O 2 /L − 150 mL O 2 /L) = 4.75 L/min. Cardiac output may also be estimated with the Fick principle using production of carbon dioxide as a marker substance. [3]
Pulse pressure is calculated as the difference between the systolic blood pressure and the diastolic blood pressure. [3] [4]The systemic pulse pressure is approximately proportional to stroke volume, or the amount of blood ejected from the left ventricle during systole (pump action) and inversely proportional to the compliance (similar to elasticity) of the aorta.
Impedance cardiography (ICG) is a non-invasive technology measuring total electrical conductivity of the thorax and its changes in time to process continuously a number of cardiodynamic parameters, such as stroke volume (SV), heart rate (HR), cardiac output (CO), ventricular ejection time (VET), pre-ejection period and used to detect the impedance changes caused by a high-frequency, low ...
The Frank-Starling mechanism allows the cardiac output to be synchronized with the venous return, arterial blood supply and humoral length, [2] without depending upon external regulation to make alterations. The physiological importance of the mechanism lies mainly in maintaining left and right ventricular output equality. [1] [3]