Wiggers diagram

Wiggers Diagram, showing various events of a cardiac cycle.

A Wiggers diagram is a standard diagram used in cardiac physiology.

The X axis is used to plot time, while the Y axis contains all of the following on a single grid:

• Blood pressure
  • Aortic pressure
  • Ventricular pressure
  • Atrial pressure
• Ventricular volume
• Electrocardiogram
• Arterial flow (optional)
• Heart sounds (optional)

By illustrating the coordinated variation of these values, it becomes easier to illustrate the relationship between these values in the cardiac cycle.

Etymology

It is named after Dr. Carl J. Wiggers, M.D.. The diagram is frequently called a "Wigger's diagram", but this is incorrect.

Events

	Phase	EKG	Heart sounds	Aortic valve	Mitral valve
A	Atrial systole	P	S4*	closed	open
B	Ventricular systole - Isovolumetric/isovolumic contraction	QRS	S1 ("lub")	closed	closed
C1	Ventricular systole - Ejection 1	-		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

• 

  Ventricular systole

• 

  Cardiac diastole

• 

  ECG

• 

  The EKG complex. P=P wave, PR=PR interval, QRS=QRS complex, QT=QT interval, ST=ST segment, T=T wave

See also

• Pressure volume diagram

External links

• Flash animation at utah.edu
• Diagram at mmi.mcgill.ca
• Slides at ouhscphysio.org
• Diagram at arizona.edu
• Diagram at cals.ncsu.edu
• Biography of Carl Wiggers
• isometric+period+of+cardiac+cycle at eMedicine Dictionary