Cardiac misc Flashcards
CO equation
CO = SV x HR
SV is determined by preload, afterload and contractility.
MAP and it’s equation
MAP is the measure of the average pressure in the arterial system during ventricular contraction and relaxation. (60% of diastolic pressure and 40% of systolic pressure).
MAP = CO x PVR
What 2 factors determine PVR?
Changes of the radius of arterioles and viscosity of the blood.
In what 2 general ways does the body maintain blood pressure?
1 Adjusting CO to compensate for changes in PVR
2 Adjusting PVR to compensate for changes in CO
What 3 factors reflect systolic blood pressure
1 Stroke Volume: The volume of blood ejected from the ventricles with each beat.
2 The rate and force with which blood is ejected.
3 The elasticity, or compliance of the aorta and large arteries.
What are the 4 phases of the cardiac cycle
Ventricular systole :
1 Isovolumetric contraction period
2 Contraction period
Diastole:
1 Isovolumetric relaxation
2 Rapid filling period
The difference between end diastolic volume and end systolic volume is known as?
Stroke Volume
What is preload?
Represents the volume work of the heart or the amount of blood the ventricle must pump.
It is considered the end-diastolic pressure when the ventricle has been filled.
What is the Frank-Starling mechanism?
The increased force of contraction that accompanies an increase in ventricular end-diastolic volume.
What is after load?
The pressure in which the muscle exerts its contractile force in order to move blood into the aorta.
What impacts after load?
Blood pressure : Systemic for L heart, Pulmonary for R heart.
Narrowing of the aortic valve.
Two broad categories of heart failure and two more specific.
Right and Left
AND
Systolic dysfunction and diastolic dysfunction
Systolic dysfunction (reduced ejection fraction) ie impacted by what two determinants?
Impaired contractility: 1) CAD 2) chronic volume overload ( 3) dilated cardiomyopathy and Increased afterload: 1)advanced aortic stenosis 2)uncontrolled severe hypertension
