Cardiovascular anatomy and physiology 4 Flashcards
What are the four phases of the ventricular pressure-volume loop?
period of ventricular filling (bottom horizontal line)
isovolumetric contraction (right vertical line)
ventricular ejection (top horizontal line)
isovolumetric relaxation (left vertical line)
_________ is the percentage of how much blood is pumped by the heart during each beat
The ejection fraction
The amount of work the ventricle must do to eject its stroke volume is called
the external work
The LV’s external work can be estimated by
multiplying the stroke volume (width) by the mean aortic pressure (height)
An EF of ___________ indicates severe dysfunction
<25%
An EF of ____________ indicates moderate dysfunction
26-40%
An EF of __________- indicates mild dysfunction
41-49%
An EF of ____________- is normal
> 50%
The morphology of the pressure-volume loop is affected by changes in
preload, contractility, and afterload
How does an increased preload affect the PV loop?
PV loop gets wider but returns to the original end-systolic volume
How does a decreased preload affect the PV loop?
PV loop gets narrower but returns to the original end-systolic volume
How does an increased contractility affect the PV loop?
PV loop gets wider, taller, and shifts to the left
How does a decreased contractility affect the PV loop?
PV loop gets narrower, shorter, and shifts to the right
How does an increased afterload affect the PV loop?
PV loop gets narrower, taller, and shifts the ESV to the right
How does a decreased afterload affect the PV loop?
PV loop gets wider, shorter, and shifts the ESV to the left
An example of decreased preload would be
furosemide
The _____ & _______________ arise from the aortic root
left and right coronary arteries (LCA & RCA)
The LCA divides into the
left anterior descending and circumflex arteries
The left anterior descending artery perfuses the
anterolateral & apical walls of the left ventricle as well as the anterior two thirds of the interventricular septum
The EKG leads that correlate with the left anterior descending artery are
V1-V4
The circumflex artery supplies the
left atrium
lateral & posterior walls of the LV
The EKG leads that correlate with the circumflex arteries are the
I, aVL, V5-V6
The right coronary artery perfuses the
right atrium, right ventricle, interaterial septum and the posterior third of the interventricular septum
The EKG leads that correlate with the right coronary artery include
II, III, aVF
The posterior descending artery perfuses the
inferior wall
Blood returning to the left side of the heart by way of the Thebesian circulation contributes to
a small amount of anatomic shunt
When using TEE/TTE, the best view for diagnosing myocardial ischemia is
the midpapillary muscle level in short-axis
The coronary sinus resides on the
heart’s posterior surface and it returns cardiac venous blood to the right atrium
The origin of the posterior descending artery defines
coronary dominance
The SA node receives its blood supply from the _______ in about 70% of patients
RCA
The AV node receives its blood supply from the ________ in about 80% of patients
RCA
The Bundle of His is perfused by the _______ in about 75% of patients
LCA
The left and right bundle branches are almost exclusively supplied by the
LCA
What are the three main coronary veins and their corresponding arteries?
great cardiac vein (LAD)
middle cardiac vein (PDA)
anterior cardiac vein (RCA)
Most blood returns to the
coronary sinus which can be cannulated to administer retrograde cardioplegia
The second best view for diagnosing left ventricular ischemia is the
apical segment also in short axis
Mediators of coronary vasodilation include: (select 2)
a. adenosine
b. beta-2 stimulation
c. alpha-1 stimulation
d. hypocapnia
a. adenosine
b. beta-2 stimulation
The heart matches its blood flow to
its metabolic needs
At rest, the coronary blood flow is
225-250 mL/min.
What is the coronary blood flow equation?
coronary blood flow= Coronary perfusion pressure/coronary vascular resistance
What is the coronary perfusion pressure equation?
coronary perfusion pressure= aortic DBP-LVEDP
Coronary blood flow autoregulates between a MAP of
60-140 mmHg
_________ is the most important determinant of coronary vessel diameter.
Local metabolism
Autoregulation of coronary blood flow is the net effect of three things:
local metabolism
the myogenic response
the autonomic nervous system
A good example of when the ANS affects coronary vascular tone over that of local metabolism is
patients with prinzmetal angina have overactive coronary alpha receptors that cause intense vasoconstriction and chest pain
