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. 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 pressure Ventricular pressure Atrial pressure Ventricular volume Electrocardiogram Arterial flow (optional) Heart sounds (optional)
The Wiggers diagram clearly illustrates the coordinated variation of these values as the heart beats, assisting one in understanding the entire cardiac cycle.
Events Phase EKG Heart sounds Semilunar valves Atrioventricular valves A Atrial systole P S4* closed open B Ventricular systole – Isovolumetric/isovolumic contraction QRS S1 ("lub") closed closed C1 Ventricular systole – Ejection 1 ST open closed C2 Ventricular systole – Ejection 2 T open closed D Ventricular diastole – Isovolumetric/isovolumic relaxation – S2 ("dub") closed closed E1 Ventricular diastole – Ventricular filling 1 – S3* closed open E2 Ventricular diastole – Ventricular filling 2 – closed open
Note that during isovolumetric/isovolumic contraction and relaxation, all the heart valves are closed; at no time are all the heart valves open. *S3 and S4 heart sounds are associated with pathologies and are not routinely heard.
Additional images
See also Pressure volume diagram
References