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Atrial systole overlaps the end of the diastole, occurring in the sub-period known as ventricular diastole–late (see cycle diagram). At this point, the atrial systole applies contraction pressure to 'topping-off' the blood volumes sent to both ventricles; this atrial contraction closes the diastole immediately before the heart again begins ...
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 ...
A Wiggers diagram, showing various events during systole (here primarily displayed as ventricular systole, or ventricular contraction). The very short interval (about 0.03 second) of isovolumetric, or fixed-volume, contraction begins (see upper left) at the R peak of the QRS complex on the electrocardiogram graph-line. + Ejection phase begins ...
During most of the cardiac cycle, ventricular pressure is less than the pressure in the aorta, but during systole, the ventricular pressure rapidly increases, and the two pressures become equal to each other (represented by the junction of the blue and red lines on the diagram on this page), the aortic valve opens, and blood is pumped to the body.
Wiggers diagram of the cardiac cycle, with isometric contraction marked at upper left. In cardiac physiology, isometric contraction is an event occurring in early systole during which the ventricles contract with no corresponding volume change (isometrically). This short-lasting portion of the cardiac cycle takes place while all heart valves ...
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 ...
In human physiology, the atria facilitate circulation primarily by allowing uninterrupted venous flow to the heart during ventricular systole. [22] [23] By being partially empty and distensible, atria prevent the interruption of venous flow to the heart that would occur during ventricular systole if the veins ended at the inlet valves of the ...
English: A Wiggers diagram, showing the cardiac cycle events occuring in the left ventricle. In the atrial pressure plot: wave "a" corresponds to atrial contraction, wave "c" corresponds to an increase in pressure from the mitral valve bulging into the atrium after closure, and wave "v" corresponds to passive atrial filling.