2) QRS Wave (Complex) : represents rapid ventricle depolarization as the AP spreads through ventricular contractile fibres. 3) T Wave : represents ventricular repolarization occurring just as the ventricles are starting to relax.
Time span between waves is also taken into account.
P-Q Interval : beginning of P to beginning of QRS waves and represents conduction time from beginning of atrial excitation to the beginning of ventricle excitation. Another way: time for an AP to travel through the atria, AV node, and the remaining fibres of the conduction system. S-T Segment : beginning at the end of S wave and ends at the beginning of the T wave representing the time when the ventricular contractile fibres are depolarized during plateau phase. Q-T Interval : beginning of the QRS complex to the end of the T wave and represents the time from beginning of ventricular depolarization to the end of ventricular repolarization.
Cardiac Cycle
Single Cardiac Cycle : all the events associated with one heartbeat.
Systole : Refers to phase of contraction
Diastole : Refers to phase of relaxation
1) Atrial Systole/Ventricular Diastole :
The Atria are CONTRACTING (0.1 sec) – Ventricles are RELAXED
End-Diastolic Volume (EDV): the blood volume each ventricle contains at the end of its relaxation period.
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