Cardiac Exam Lecture 6

Question 1

Draw Wiggers Diagram

Question 2

Identify the phases of the cardiac cycle as delineated by valve openings and closings

Question 3

Explain the mechanisms responsible for “a, c, and v” waves of the venous pulse

Answer 3

Venous Pulse:

a wave: atrial contraction/ atrial kick

c wave: contraction of ventricles

v wave: as blood accumulates on venous side, mitral valve opens,

Question 4

Explain the causes of the first and second heart sounds and their position in the cardiac cycle

Answer 4

First Heart Sound: Mitral Valve Closing (loud and violent because ventricles are contracting/ “isovolumetric contraction”)

Second Heart Sound: Aortic Valve Closing (start of isovolumetric relaxation)

Question 5

Draw and explain a normal LV pressure-volume diagram and how changes in preload, afterload, and contractility affect stroke volume

Question 6

Define systolic heart failure

Answer 6

Heart Failure: a condition in which the heart fails to provide cardiac output to meet the needs of the body (decreased ventricular contractility)

Question 7

Define ejection fraction

Answer 7

Ejection Fraction:

The fraction of blood ejected during one stroke of the heart

Normal is about 60%

Clinical index of LV contractility

(EDV-ESV)/EDV x 100

Question 8

Define the various factors that determine and affect preload, afterload and contractility

Answer 8

Preload:

• pressure gradient btw atria and ventricles
• time for ventricular filling
• ventricular compliance
• atrial kick

Afterload:

• aortic pressure (hypertension)
• Ventricular outflow tract resistance (stenosis or insufficiency)
• Ventricular size (dilated hearts have higher tension, larger afterload)

Contractility:

• SNS and PSNS
• Drugs (positive inotropic agents)
• Disease

Question 9

Define heart failure