CAM201 Lecture Notes - Lecture 2: Wiggers Diagram, Cardiovascular Physiology, Coronary Artery Disease
Learning Objectives
• Describe the electrophysiological basis fro impulse generation
• Describe the basic components of the ECG waveforms and normal values of the major
intervals
• Understand and relate the orientation of ECG leads to the electrical events that occur in the
heart
Introduction to Dipoles
Two adjacent cells with different electrical potentials create a dipole
• Dipole: a pair of equal and oppositely charged poles separated by a distance
• Current will flow from negative/reference point to the positive/sensor
When both cells are depolarised, there is no potential difference
When the first cell depolarises, the dipole then reverses
• There is now current flow from right to left
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• When both cells are repolarised, there is no potential difference and no dipole
A dipole will set up a current in a conductive medium like water
• Orientation of dipole and placement of electrodes matter
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find more resources at oneclass.com
The Heart and Dipoles
Our bodies are around 90% water and are very good at conducting electrical impulses/signals
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find more resources at oneclass.com
Document Summary
Two adjacent cells with different electrical potentials create a dipole: dipole: a pair of equal and oppositely charged poles separated by a distance, current will flow from negative/reference point to the positive/sensor. When both cells are depolarised, there is no potential difference. When the first cell depolarises, the dipole then reverses: there is now current flow from right to left, when both cells are repolarised, there is no potential difference and no dipole. A dipole will set up a current in a conductive medium like water: orientation of dipole and placement of electrodes matter. Our bodies are around 90% water and are very good at conducting electrical impulses/signals. Fun fact: 2 billion cells in the heart, depolarisation occurs on a huge scale: the spread of depolarisation in the heart involves many dipoles, oriented in different directions simultaneously, these dipoles have many different directions. The measured voltage at any instant results from the net dipole.
