03 Mechanical Properties 2

Question 1

List the cardiac cycle in sequence

Answer 1

Atrial systole
Isovolumetric contraction
Rapid ejection
Reduced ejection
Isovolumetric relaxation
Rapid filling
Reduced filling

Question 2

Briefly describe the significant events that occur during atrial systole

Answer 2

• P wave
• Contraction of atria to force blood into ventricles through open atrioventricular valves
• “a” wave sent to the jugular vein
• May have abnormal 4th heart sound which can be caused by tricuspid valve incompetence, pulmonary embolism or congestive HF

Question 3

Briefly describe the significant events that occur during isovolumetric contraction

Answer 3

• This is ventricular contraction without change in volume
• QRS wave
• 1st heart sound - lub

Question 4

Briefly describe the significant events that occur during rapid ejection

Answer 4

• This is when semilunar valves open to allow ventricular ejection of blood into arteries
• Ventricular pressure exceeds aortic pressure
• c wave into jugular vein from the right ventricles

Question 5

Briefly describe the significant events that occur during reduced ejection

Answer 5

• End of systole
• T wave
• Valves begin to close

Question 6

Briefly describe the significant events that occur during isovolumetric relaxation

Answer 6

• 2nd heart sound - dub
• v wave into the jugular veins as blood push against tricuspid valve
• Dichrotic notch due to rebound pressure wave against aortic valve as distended aortic wall relaxes

Question 7

Briefly describe the significant events that occur during rapid filling

Answer 7

• Atrial pressure exceeds ventricular pressure
• Opening of atrioventricular valves
• Abnormal 3rd heart sound may occur due to turbulent flow by mitral valve incompetence or hypertension

Question 8

Describe the differences between pulmonary and systemic cardiac cycle

Answer 8

Pattern identical

Quantitatively: pressure is lower in the right side

Question 9

Define cardiac contractility and what is a simple measurement of it

Answer 9

Contractile capability of the heart

Measured from ejection fraction