Cardiac Cycle And Performance Flashcards
Atrial Systole is represented by what on the ECG?
P wave.
Briefly describe the events of atrial systole.
Atria contracts, The mitral valves open, blood rushes from atrium into ventricles causing an increase in ventricular pressure.
Relating to heart sound, what is S1?
S1 is the Lub of a normal heartbeat. It occurs during the closure of the mitral and tricuspid valves (AV valves).
Relating to heart sound, what is S2?
S2 is the dub of the normal heartbeat. It is the closure of the aortic and pulmonary valves.
Which part of am ECG is represented by the isovolumetric ventricular contraction?
QRS complex
Briefly describe isovolumetric ventricular contraction (B)
Includes the left ventricle contracting and the mitral and tricuspid valve closing. Once closed, ventricular pressure increases drastically but the ventricle volume remains constant due to the valves being closed.
Describe Part C of the cardiac cycle.
C is referred to as the Rapid ventricular ejection. This is where the ventricles continue to contract until maximum.
Once he ventricle pressure > aortic pressure, the aortic valves open and blood then rushes into the aorta.
Ventricle pressures decreases and aortic pressure increases. The atria pressure then slowly begins to increase.
Part C is represented as the end of the ST segment on a ECG.
Describe part D of the cardiac cycle.
D refers to as the reduced ventricular ejection.
This is where the ventricles pushed blood into the arteries. Ventricle pressure and volume decreases
D represents the T wave on an ECG.
Describe part E of the cardiac cycle.
E refers to as the Isometric volume relaxation. Once ventricle pressure is < aortic pressure, the aortic valve closes.
Once the aortic valve close is produces a dicrotic notch
Represents the end of the T wave
Describe part F & G of the cardiac cycle.
F & G represents Rapid and Reduced ventricular fillings.
F- Rapid ventricular filling - ventricles is relaxed. Once left ventricle reaches slight below atria pressure, the mitral valve opens and the same process is repeated as Part A.
G- Reduced ventricular fillings- ventricles relaxed. Longest part of the cardiac cycle.
When inotrophy is increased, what is the effect on the frank sterling curve?
When increased, the FS curve shifts up and to the left. There is an increase in SV and a decrease in LVEDP.
When inotrophy is decreased, what is the effect on the frank sterling curve?
When there is a decreased, the FS curve shifts down resulting in an decrease in SV and a increase in LVEDP.
Discuss how the preload, afterload and contractility affect cardiac output.
If Preload and contractility increases, SV increases therefore increase CO
If Afterload increases, SV decreases and CO decreases.
Explain the stages of the ventricular volume- pressure loop.
(4-1) Ventricular filling -> mitral valves closes -> Isovolumetric contraction (1-2) -> Aortic valves open -> Ventricular ejection (2-3) -> Aortic valves closes -> Isovolumetric relaxation (3-4) -> Mitral valves open
What effect does the afterload have on the stroke volume of the ventricular volume pressure loop?
Once the afterload increases, the stroke volume decreases, and aortic pressure increases.
What effect does the preload have on the stroke volume of the ventricular volume pressure loop?
If the preload increases, SV increases.
What effect does the contractility have on the stroke volume of the ventricular volume pressure loop?
In contractility increases, SV increases and ESV decreases
What caused the spilling of the second heart (S4) sounds?
When the aortic valve closes before the pulmonary valve.
A delay in the closing of the pulmonary valve.
State the significance/ effect of digitalis (Digoxin).
It inhibits the Na/K+-ATP — increases intercellular NA+ — decreases the NA+ gradient — increases the intercellular Ca2+ via the Na+-Ca++ exchanger.
List positive intropic factors.
— NE
— HR
— Drugs ex. Digitalis (Digoxin)
— Epinephrine
— ECF Ca2+
Note: these factors increase contractility.
List negative intropic factors.
— AcH and cholinergic agonists
— B- blockers (Propranolol, atenolol)
— Ca channel blockers
— Removal of Ca2+ from ECF
— Acidosis & hypoxia
— HF
Note: these factors decrease contractility.
