Cardiac Exam Lecture 6 Flashcards
Draw Wiggers Diagram
Identify the phases of the cardiac cycle as delineated by valve openings and closings
Explain the mechanisms responsible for “a, c, and v” waves of the venous pulse
Venous Pulse:
a wave: atrial contraction/ atrial kick
c wave: contraction of ventricles
v wave: as blood accumulates on venous side, mitral valve opens,
Explain the causes of the first and second heart sounds and their position in the cardiac cycle
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)
Draw and explain a normal LV pressure-volume diagram and how changes in preload, afterload, and contractility affect stroke volume
Define systolic heart failure
Heart Failure: a condition in which the heart fails to provide cardiac output to meet the needs of the body (decreased ventricular contractility)
Define ejection fraction
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
Define the various factors that determine and affect preload, afterload and contractility
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
Define heart failure