cardiac cycle

CARDIAC CYCLE

• one cardiac cycle : one complete cycle that encompasses atrial and ventricle contraction and relaxation

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• P wave	atrial depolarization & contraction	fills the ventricles	cuspid valves open while valves of vena cava and pulmonary veins are closed
  QRS complex	atrial repolarization and relaxation & simultaneous ventricular depolarization and contraction	empties the ventricles	cuspid valves are closed while semilunar valves are open
  T wave	ventricular repolarization and relaxation	heart relaxes	cuspid and semilunar valves are closed
  pause	myocardium at rest	atria fill after a pause of some length	valves of vena cava and pulmonary veins open so atria can fill