This lecture discusses how electrical activity in the heart is recorded outside the body as an electrocardiogram (ECG) and how the electrical activity gives rise to cardiac contraction.
Pre-lecture reading CVSL5 – ECG, E-C coupling
- The ECG is a recording of the electrical events occurring in the heart from the surface of the body.
- Cyclical depolarization and repolarization gives rise to waves on the ECG.
- The ECG provides information on the cardiac rate and rhythm, pattern of depolarization, mass of actively depolarizing muscle and presence of cardiac ischemia / infarction.
- Cardiac depolarization leads to cardiac contraction.
- The key event triggering cardiac contraction is the entry of calcium during depolarization.