Look for the examples of Wiggers diagrams on this page. You can review while studying the diagram. The diagram is named after its developer, Dr. Carl J. Wiggers and is used in teaching cardiac physiology. The first Wiggers diagram is shown in the figure below along with the explanation. View the diagrams and learn about them in the following images.
A Wiggers diagram shows the changes in ventricular pressure and volume during the cardiac cycle. Often these diagrams also include changes in aortic and atrial pressures, the EKG, and heart sounds. Diastole starts with the closing of the aortic valve (the second heart sound). Shortly after, ventricular filling begins when the mitral valve open. This is the lowest volume on the ventricular volume curve. Volume rapidly increases as the atria and ventricles fill. Now take a look at the following diagram that is drawn manually and the one with the heart on it.
Ventricular pressure remains low during this filling. Ventricular volume increases a little more when the atria contract. This contraction causes a small increase in atrial and ventricular pressures (and is associated with the P wave of the ECG). By illustrating the coordinated variation of these values, it becomes easier to illustrate the relationship between these values in the cardiac cycle.
Studying this diagram will give you more insight into the cardiac cycle. All of the diagrams are printable in high quality, so just click the save menu and you can print it out from your browser!