Class 7 Flashcards
What is defined as the property of the contractile myocytes that account for the strength of contraction?
Contractility
Contractibility is also known as
Inotropic state, strong or weak
What is contractility related to?
Intrinsic cellular mechanisms that regulate the interaction between actin and myosin
Is contractility independent of the preload and afterload?
Yes
What haemodynamic parameters can be employed to evaluate the cardiac performance? (5)
- Ventricular end diastolic pressure
- Cardiac index
- Stroke volume
- Ejection fracture
- Peak rate of ventricular pressure development during isovolumetric contraction
- End systolic pressure volume relationship
- Maximum velocity of muscle shortening
Any condition resulting in inadequate systolic emptying will lead to what happening to the ESV?
Increase in ESV
Regardless of its compliance an increase in EDV will give rise to what happening to EDP?
Increase
How to give a cardiac output the heart with a greater contractility will result in a higher or lower EDP?
Lower
In a failing heart, any increase in preload will do what two stroke volume?
Has very little effect on stroke volume
Concentric hyper trophy is what to wall thickness?
Increasing well fitness
An increase in contracutility will do what to stroke volume at a given preload and thus generate a higher or lower cardiac index?
Increase, higher
What indirectly reflects the extent of ventricular fibre shortening 
Stroke volume
What is defined as a fraction of end-diastolic volume ejected from the ventricle during each systolic contraction?
Ejection fraction
How do you calculate ejection fraction?
EF = SV/EDV
EF depends on the variation of what?
Afterload
What is the value corresponding to the rate of pressure rises in the ventricular chamber during isovolumetric contraction?
Peak rate of ventricular pressure development
Stronger the force of contraction, is the slope steeper or less steep for rate of ventricular pressure development?
Steeper
When is the highest DP/DT?
Just before the opening of semi lunar valves
Series of successfully stronger contraction can be observed when the muscle fibre receives closely spaced stimuli describes what phenomenon?
Treppe or Bowditch effect
What ion is immediately toxic to the heart?
Calcium
Any increase in entropy will do what to the ESPVR?
Shift it upward to the left
What is the true indicator of contractility at a given inotropic state?
Maximum velocity of muscle shortening or Vmax
Can you measure Vmax?
No
When contractility of the ventricle is increased, what happens to the force velocity curve?
It shift up and to the right
Increase in Vmax means an increase in contractility, what does it do to ejection velocity, stroke volume, ESV, and ESP?
- increase ejection velocity
- Increase stroke volume
- Reduce ESV
- Reduce ESP
With an increase in contractility, what does it do to ESV, EDV and stroke volume?
- large decrease in ESV
- moderate decrease in EDV
- Overall increase in stroke volume
Narrow opening of aortic valve with resistance to flow describes what?
Aortic stenosis
Ian aortic stenosis can the valve close completely open completely?
Close completely, cannot be fully opened
When will you hear a systolic murmur?
During aortic stenosis, between S1 and S2, During the ejection phase or when the aortic valve is supposed to open
Aortic stenosis does what to velocity of the blood?
Increases
Aortic stenosis causes an increase or decrease in LVP do to increase and after load?
Increase
Increase in afterload causes a huge increase or decrease in ESV?
Increase
Aortic stenosis result in a decrease or increase in stroke volume?
Decrease
Chronic left ventricular volume and pressure overload from aortic stenosis will lead to onset of what?
Pulmonary hypertension
Pulmonary hypertension results in what?
Right ventricular disfunction and eventually congested heart failure
Increase resistance to flow across the mitral valve during ventricular filling and giving rise to the elevation of the left atrial pressure describes what?
Mitral stenosis
Mitral stenosis could lead to a huge reduction in what?
LVEDV
Huge reduction in LVEDD from mitral stenosis does what two stroke volume in cardiac output?
Decreases both
With mitral stenosis when do you hear a diastolic murmur?
Between S2 and S one due to higher velocity of blood flow through stenotic mitral valve into left ventricle
What is aortic insufficiency?
Incomplete closure of aortic valve, no problem opening
What does incomplete closure of aortic valve give rise to?
Regurgitation of blood back to the left ventricle
Regurgitation does what to pre-load?
Increase it
When is there no true ventricular isovolumetric relaxation or contraction phase?
In an aortic regurgitated heart/aortic insufficiency
When do you hear a diastolic murmur in aortic insufficiency?
Between us two and S one, during ventricular diastolic due to backflow of blood from aorta back to left ventricle
What is the incomplete closure of the mitral valve?
Mitral insufficiency
What does mitral insufficiency do?
Incomplete closure of mitral valve, Bloodflows back to left atrium during ventricular contraction
When blood flows back to left atrium during ventricular contraction what does this due to left atrial pressure?
Causes sharp rise in pressure during ventricular system
When can you hear the systolic murmur for mitral insufficiency?
Between S1 and S2, the backflow of blood to left atrium during ventricular systole
Is there a true isovolumetric relaxation and contraction phase is in my phone regurgitated heart?
No
In mitral regurgitated heart what happens to afterload?
Left ventricle afterload is reduced because total outflow resistance is reduced
My troll insufficiency leads to what happening to LVEDV and LVESV?
Sharp Increase, huge decrease
