Cardiac Cycle Flashcards
What is the cardiac cycle?
Which ventricle does the cycle generally refer to?
All the events associated with one heart beat. Contract then relax.
Left Ventricle during contraction.
What is the Q-T interval from the ECG? and what does it mean in the cardiac cycle?
Time from the onset of the QRS complex to the end of the T wave and is an estimate of the time the ventricles are contracting.—ventricular systole.
What is the T-Q interval from the ECG? and what does it mean in the cardiac cycle?
Time from the end of the T wave to the beginning of the QRS complex and is an estimate of the time the ventricles are relaxing…Ventricular diastole.
Systolic period.
What is happening to the ventricle?
What are the two phases of this period?
Ventricle is CONTRACTING.
Isovolumic contraction phase.
Ventricular ejection phase.
Diastolic period.
What is happening to the ventricle?
What are the two phases of this period?
Ventricle is RELAXED.
Isovolumic relaxation phase.
Passive ventricular filling phase.
Atrial systolic phase.
What is the maximum volume of the left ventricle? What is this called?
What is the minimum volume of the left ventricle? What is this called?
What is the difference, and what is this value called?
Converted into a percentage of question 1, what is the number and what does this represent? What is the normal average?
130 mL EDV–End Diastolic Volume.
60 mL ESV–End Systolic Volume.
70 mL SV–Stroke Volume.
54% SV/EDV = Ejection Fraction.
What happens during the Passive Ventricular Filling Phase?
What is open and why? Use numbers.
How much blood moves?
What interesting action happens with the ECG?
The Bicuspid (mitral) valve is open, Lt atrial pressure (10 - 12) > Ventricular P (9).
The aorta is closed LV 9 < LA 100.
80% of blood volume enters atria and ventricle during this time.
ECG P wave begins (depolarization) before the atria actually contracts in Atrial Systole.
Atrial Systolic Phase
What happens to the atria.
What is the change in blood volume?
What is the change in pressure?
ECG P wave–depolarizes the atria, then the atria contract. Pressure in the atria forces blood into the ventricle.
Blood volume in the ventricle only increases about 5 mL.
The increase in ventricular blood volume creates a rise in both atrial > and ventricular pressure.
Isovolumetric Contraction
WHat valve closes?
What does the ventricle do?
What happens with pressure? Where do aortic and ventriclar pressures intersect?
Mitral valve shuts due to increase vent. pressure.
The ventricle initiates a isovolumic (no change in volume) contraction.
Pressure in the Ventricle builds significantly.
The ventricle and Aorta pressures meet at 80mmHg.
Aorta valve opens.
Ventricular Ejection
What happens?
How does pressure change?
Blood flows out of and through the aorta.
Ventricular pressure rises to a peak and then begins to decline. When it falls below aortic pressure, the semilunar valves close.
