Cardiac Cycle Flashcards
8 month old
Rapid and labored breathing (O2 hungry)
Fatigue on feeding (weakness)
Slow weight gain
Cyanotic, palpable thrill (systolic murmur) over left lower sternal border
Mother’s history = rubella infection during pregnancy !
Diagnosis = congenital defect/valvular heart disease
One cardiac cycle
Systole —> next systole
About 0.8 seconds
3 stages of ventricular systole
- Isovolumetric contraction - volume doesn’t change
- Rapid ejection
- Reduced ejection
Ventricular diastole
2/3 of the cardiac cycle
- Isovolumetric relaxation
- Rapid filling
- Reduced filling
Function of the heart diaphragm
Changes the pressure in the ventricles..to allow filling or ejection
Pulling out diaphragm = larger volumer —> filling…aortic/pulm valves close and tricupsid and mitral open
Isovolumetric contraction (systole)
All 4 valves are closed
Ventricles are contracting
Pressure is super high…right before pushes open aortic/pulm valves
Isovolumetric relaxation
Pressure falls as blood flows out of ventricles…and its not good enough to keep outflow valves open
All 4 valves become closed
AV valves open since ventricular pressure is so low
Increased afterload =
Aortic valve opens later
EDV doesnt change
But ESV is increased…therefore SV decreases
Increased preload
EDV increases
SV volume increases as a result
Increased contractility
Lowers ESV
Therefore increases SV
1st heart sound
Loudest and longest
During isovolumetric contraction phase
Caused by:
Oscillation of blood in ventricular chambers
Vibration of chamber wall during contraction
Closing of mitral and tricupsid valves
2nd heart sound
Short and low intensity
Happens during the isovolumetric relaxation phase
Closure of aortic/pulm valves
3rd heart sound
Usually not audible
Caused by vibration of the ventricular wall during ventricular rapid filling
4th heart sound
Also known as atrial heart sound
Usually not audible
Caused by oscillation of blood in atria during contraction
Fallot’s tetralogy
Common if mother has a rubella infection while pregno
VSD
Obstruction to RV outflow
Overriding aorta that receives blood from both ventricle
RV hypertrophy
—> has to pump against greater pressure