Cardiac Cycle Flashcards
Where does contraction of the ventricles begin?
Apex of the heart
What is the first heart sound?
- S1
- Closing of the AV valves
- signal end of diastole and beginning of systole
What is isovolumetric ventricular contraction?
- Early ventricular contraction
- pressure in ventricles has not yet exceeded aorta and pulmonary arteries
- no change in volume yet
What is isovolumetric ventricular relazation?
- After ventricles pump blood
- Ventricular pressure is still greater than atria, so AV valves are closed
What is the second heart sound?
- S2
- Pulmonary and aortic valves close
- signal the end of systole, and beginning of diastole
What is valvular stenosis?
- if valve doesn’t open as easily or is narrowed
- more pressure needed to overcome stenosis, therefore more work
- results in turbulent flow/murmer
What is an incompetent valve?
- AKA regurgitant
- Valve can’t hold pressure back, so some blood leaks backwards into ventricle
- Results in turbulent flow/murmer
When would the time between S2 sounds be greatest?
-during inspiration
What is the equation for ejection fraction?
EF = SV/EDV
SV = systolic volume EDV = End diastolic volume
At what EF would a heart transplant be necessary?
<25%
What does the sequential contraction of the atria and ventricle depend on?
Cardiac pacemaker and conduction system
IS the intrinsic heart rate of the AV node faster or slower than the SA node?
Slower
What does the P wave represent?
-Atrial depolarization
What does the QRS complex represent?
-Ventricular depolarization
What does the T wave correspond to?
-Ventricular repolarization
What does the QT-interval correspond to?
The time from the first ventricular depolarization to the last ventricular repolarization
What does the PR-interval correspond to?
-Time from initial atrial depolarization to initial ventricular depolarization
What qualifies as bradychardic?
<60 BPM
What qualifies as Tachycardic?
> 100 BPM
What does S3 represent?
decrease in the contractility of the ventricles
What condition leads to increased preload?
Congestive Heart Failure
How does afterload affect stroke volume?
- Inverse relationship
- Increased afterload = decreased stroke volume
What is the ideal ejection fraction?
60% of end systole
What is AOA Asian Dude’s formula for MAP?
MAP-RAP = CO-SVR
- RAP = Right atrial pressure
- SVR = Systemic Vascular Resistance
