The larger QRS complex of ventricular depolarization (up to 10 milliseconds), consisting of one or more of the following:
-the Qwave, a downward deflection from septal depolarization -the R wave, an upward deflection from ventricular depolarization -the S wave, a downward deflection following an R wave
A T wave of ventricular repolarization, or recovery (duration relates to QRS).
The electrical impulse slightly precedes the myocardial contraction that it stimulates. The relation of electrocardiographic waves to the cardiac cycle is shown below.
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