lOMoARcPSD|21646696
Ch 25- Assessment of Cardiac Function
, lOMoARcPSD|21646696
Ch 25- Assessment of Cardiac Function
Overview of Anatomy and Physiology
● Three layers
○ Endocardium- inner layer, lines the inside of the heart and valves
○ Myocardium- made up of muscle fibers and is responsible for the
pumping action
○ Epicardium- the exterior layer of the heart
● Four chambers- two top chambers are atria and two bottom
chambers are ventricles
○ Right side has less pressure, left side has more pressure
● Heart valves
○ Atrioventricular valves- tricuspid (right side of heart), bicuspid/
mitral (left side of the heart)
○ Semilunar valves - aortic semilunar (left side of the heart),
pulmonary semilunar (right side of the heart)
● Vasculature
○ The left and right coronary arteries which branch of the aorta
supply the heart tissue, which extracts 70-80% of the oxygen
○ Tachycardia can lead to myocardial ischemia in patients due to a
decrease in diastolic time for the coronary arteries to perfuse the
heart
Conduction system (extra notes)
- SA node- primary pacemaker of the heart, in the right atrium, fires
60-100bpm inherently.
- AV node- secondary pacemaker of the heart
- Bundle of His- relays the impulse down the septum
- Perkinje fibers- the conduction impulse gets distributed throughout the
ventricles
- The nodal and perkinje cells generate and transmit electrical
impulses, and the myocytes contract
Terms - Cardiac Action Potential
● Depolarization: electrical activation of cell caused by influx of sodium
into cell while potassium exits cell
, lOMoARcPSD|21646696
● Repolarization: return of cell to resting state caused by re-entry of
potassium
into cell while sodium exits
● Refractory periods
○ Effective refractory period: phase in which cells are
incapable of depolarizing (phase 0-middle of phase 3)
○ Relative refractory period: phase in which cells require
stronger-than- normal stimulus to depolarize (end of phase 3)
● Repeated action of depolarization and repolarization is known as
the cardiac action potential
Cardiac Action Potential
Great Vessel and Heart Chamber Pressures
Cardiac Hemodynamics
● HR x SV = Cardiac output
- An increase in either of these will cause an
increase in CO Hemodynamics
Ch 25- Assessment of Cardiac Function
, lOMoARcPSD|21646696
Ch 25- Assessment of Cardiac Function
Overview of Anatomy and Physiology
● Three layers
○ Endocardium- inner layer, lines the inside of the heart and valves
○ Myocardium- made up of muscle fibers and is responsible for the
pumping action
○ Epicardium- the exterior layer of the heart
● Four chambers- two top chambers are atria and two bottom
chambers are ventricles
○ Right side has less pressure, left side has more pressure
● Heart valves
○ Atrioventricular valves- tricuspid (right side of heart), bicuspid/
mitral (left side of the heart)
○ Semilunar valves - aortic semilunar (left side of the heart),
pulmonary semilunar (right side of the heart)
● Vasculature
○ The left and right coronary arteries which branch of the aorta
supply the heart tissue, which extracts 70-80% of the oxygen
○ Tachycardia can lead to myocardial ischemia in patients due to a
decrease in diastolic time for the coronary arteries to perfuse the
heart
Conduction system (extra notes)
- SA node- primary pacemaker of the heart, in the right atrium, fires
60-100bpm inherently.
- AV node- secondary pacemaker of the heart
- Bundle of His- relays the impulse down the septum
- Perkinje fibers- the conduction impulse gets distributed throughout the
ventricles
- The nodal and perkinje cells generate and transmit electrical
impulses, and the myocytes contract
Terms - Cardiac Action Potential
● Depolarization: electrical activation of cell caused by influx of sodium
into cell while potassium exits cell
, lOMoARcPSD|21646696
● Repolarization: return of cell to resting state caused by re-entry of
potassium
into cell while sodium exits
● Refractory periods
○ Effective refractory period: phase in which cells are
incapable of depolarizing (phase 0-middle of phase 3)
○ Relative refractory period: phase in which cells require
stronger-than- normal stimulus to depolarize (end of phase 3)
● Repeated action of depolarization and repolarization is known as
the cardiac action potential
Cardiac Action Potential
Great Vessel and Heart Chamber Pressures
Cardiac Hemodynamics
● HR x SV = Cardiac output
- An increase in either of these will cause an
increase in CO Hemodynamics
