Cardiac SEE Flashcards
What is
Inotropy
Chronotropy
Dromotropy
Lusitropy
Inotropy - Contractility
Chronotropy - HR
Dromotropy - Conduction velocity
Lusitropy - Myocardial relaxation during diastole
What is the RMP and TP of the cardiac myocyte?
TP, -55
RMP, -70
What happens to the RMP when potassium is increased or decreased
Decreased K - Decreases RMP
Increased K - Increases RMP
What is the primary determinant of TP? How does hyper/hypo affect it?
Ca
Increased Ca - TP becomes positive
Decreased Ca - TP becomes more negative
What happens when RMP becomes closer to TP? What about further away?
Closer - more easily depolarized
Further - Harder to depolarize
What is the sodium-potassium ATPase pump?
Restores balance towards RMP
For every 3 Na lost, 2 K enters the cell
What drug inhibits the Sodium-potassium ATPase pump?
Digoxin
Cardiac Conduction
What happens in phase 0 of the myocyte action potential
Sodium enters the ICF
(depolarization)
What happens in phase 1 of the myocyte action potential
Cl- enters the ICF
K+ leaves the ICF
(Initial repolarization)
What happens in phase 2 of the myocyte action potential
Ca+ enters and K+ leaves
(Plateau)
What happens in phase 3 of the myocyte action potential
K leaves the ICF
(Final repolarization)
What happens in phase 4 of the myocyte action potential
Resting phase
K out
Na/K/ATPase pump working
Between what phases is the absolute refractory period?
End of phase 1 to middle of phase 3
When is the relative refractory period?
End of phase 3
What is the conduction pathway through the heart?
SA node
Internodal Tracts
AV node
Bundle of HIS
Bundle branches
Purkinje fibers
Cardiac conduction potential
What is phase 4 of the cardiac conduction potential?
Spontaneous depolarization
Na in through leaky channels
Ca channels open (T type)
What is phase 0 of the cardiac conduction potential?
Depolarization
Ca enters through L channels
What is phase 3 of the cardiac conduction potential?
Repolarization
K out
What are the RMP and TP of cardiac conduction?
RMP, -60
TP, -45
What is Reynolds number? What does it signify?
Can predict flow
<2,000 laminar
2000-4000 transitional
>4000 turbulent
How much does atrial kick contribute to Cardiac output?
20-30%
Wiggers Diagram
On the wiggers diagram when do the aortic and mitral valves open and close?
Opposite corners
On the wiggers diagram when does isovolumetric contraction and relaxation occur?
When the valves are closed
Cardiac Cycle
Normal EF? Severe?
Normal >50%
Mild > 41-49%
Moderate > 26 - 40%
Severe < 25%
Increased Preload on diagram
Decreased Preload on diagram
Increased contractility on diagram
Decreased contractility on diagram
Increased afterload on diagram
Decreased afterload on diagram
What does the Left coronary artery divide to?
Left anterior Descending and the circumflex
What does the LAD perfuse? What leads?
anterolateral and apical walls of the LV and the anterior two thirds of the septum
V1
V2
V3
V4
What does the circumflex artery perfuse? What leads?
Left atrium and posterior walls of LV
Lead I
aVL
V5
V5
What does the RCA perfuse? What leads?
R atrium
R ventricle
II
III
aVF
What does the PDA perfuse? Where does it arise from?
inferior wall
RCA
What does the Great Cardiac Vein drain?
LAD
What does the middle cardiac vein drain?
PDA
What does the anterior cardiac vein drain?
RCA
Where does almost the blood return to?
Coronary sinus
Cardiac Leads
What is the best TEE view for LV ischemia?
Midpapillary muscle level short axis
How much cardiac output does the coronaries get?
5%
What does the coronary blood flow autoregulate to?
MAP 60-140
What is a potent coronary vasodilator?
Adenosine (by product of ATP metabolism)
