Cardiac Cycle

Question 1

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 !

Answer 1

Diagnosis = congenital defect/valvular heart disease

Question 2

One cardiac cycle

Answer 2

Systole —> next systole

About 0.8 seconds

Question 3

3 stages of ventricular systole

Answer 3

1. Isovolumetric contraction - volume doesn’t change
2. Rapid ejection
3. Reduced ejection

Question 4

Ventricular diastole

Answer 4

2/3 of the cardiac cycle

1. Isovolumetric relaxation
2. Rapid filling
3. Reduced filling

Question 5

Function of the heart diaphragm

Answer 5

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

Question 6

Isovolumetric contraction (systole)

Answer 6

All 4 valves are closed

Ventricles are contracting

Pressure is super high…right before pushes open aortic/pulm valves

Question 7

Isovolumetric relaxation

Answer 7

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

Question 8

Increased afterload =

Answer 8

Aortic valve opens later

EDV doesnt change

But ESV is increased…therefore SV decreases

Question 9

Increased preload

Answer 9

EDV increases

SV volume increases as a result

Question 10

Increased contractility

Answer 10

Lowers ESV

Therefore increases SV

Question 11

1st heart sound

Answer 11

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

Question 12

2nd heart sound

Answer 12

Short and low intensity

Happens during the isovolumetric relaxation phase

Closure of aortic/pulm valves

Question 13

3rd heart sound

Answer 13

Usually not audible

Caused by vibration of the ventricular wall during ventricular rapid filling

Question 14

4th heart sound

Answer 14

Also known as atrial heart sound

Usually not audible

Caused by oscillation of blood in atria during contraction

Question 15

Fallot’s tetralogy

Answer 15

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