Cardiac cycle Flashcards
Cardiac Cycle: Atrial Systole
the contraction of the R and L atria pushing blood into the ventricles
Cardiac Cycle: Atrial Diastole
the period between atrial contractions when atria are repolarizing
Cardiac Cycle: Ventricular Systole
contraction of the R and L ventricles pushing blood into the pulmonary arteries and aorta
Cardiac Cycle: Ventricular Diastole
the period between ventricular contractions when the ventricles are repolarizing
Cardiac Cycle: Preload
refers to the tension in the ventricular wall at the end of diastole. reflects the venous filling pressure that fills the left ventricle during diastole
Cardiac Cycle: Afterload
refers to the forces that impede the flood of blood out of the heart, primarily the pressure in peripheral vasculature, the compliance of the aorta and the mass and viscosity of blood.
Cardiac Cycle: Stroke Volume (SV)
refers to volume of blood ejected by each contraction of the L ventricle. Normal SV ranges from 60-80 ml depending on age, sex, and activity
Cardiac Cycle: Cardiac Output (CO)
the amount of blood pumped from the L or R ventricle per minute. CO = SV x HR. Normal CO for adult male at rest is 4.5-5.0 L/min can increase up to 25 L/min during exercise
Cardiac Cycle: P wave
atrial depolarization
Cardiac Cycle: PR interval
time for atrial depolarization and conduction from SA node to AV node (.12-.20 sec)
Cardiac Cycle: QRS Complex
Ventricular depolarization and atrial repolarization. (0.06-0.10 sec)
Cardiac Cycle: QT Interval
time for both ventricular depolarization and repolarization. (0.20-0.40 sec)
Cardiac Cycle: ST segment
Isoelectric period following QRS when ventricles are depolarized
Cardiac Cycle: T wave
ventricular depolarization
