Summary: Teaching Experiment
SPB08c Page 1 of 11 30 May 2004
Electrocardiogram and Heart Sounds
An introduction to the recording and analysis of electrocardiograms, and the sounds of
Written by Staff of ADInstruments
The beating of the heart is accompanied by both electrical activity and sound. The pattern of electrical
activity produced by each heart beat cycle is called the electrocardiogram or ECG. The aim of this session
is to record and analyze an ECG from a student volunteer, and to examine the relationship between the ECG
and the characteristic sounds of the heart.
The heart is a dual pump that pushes blood around the body and through the lungs. Blood enters the atrial
chambers of the heart at a low pressure and leaves the ventricles at a higher pressure; it is this high
arterial pressure that provides the energy to force blood through the circulatory system. Figure 1 shows the
organization of the human heart and the circulatory system, in schematic form. Blood returning from the
body arrives at the right side of the heart and is pumped through the lungs to pick up oxygen and release
carbon dioxide. This oxygenated blood then arrives at the left side of the heart, from where it is pumped
back to the body.