CCP 216 - Cardiovascular Emergencies Flashcards
Why is TNKase preferred over alteplase in the fibrinolysis of AMI?
It is associated with a lower rate of non-cerebral bleeding complications.
Described in the ASSENT-2 trial.
Summarize the eight benefits of beta blockers in AMI:
1) Decreased MVO2.
2) Decreased risk of VF.
3) Decreased automaticity.
4) Prolonged diastole & coronary perfusion.
5) Reduction in remodelling.
6) Slows progression of atherosclerosis.
7) Inhibits platelet aggregation and thromboxane synthesis.
8) Reduction in reperfusion injury.
When are beta blockers indicated in STEMI?
Certain benefit when no reperfusion strategy is used.
Probable benefit following PCI/fibrinolysis.
What are the five types of MI?
1) Occlusive
2) Demand
3) Sudden death
4) PCI-related
5) CABG-related
80% of VF/VT occurs within the ___ hours following AMI.
12 hours.
What receptors are responsible for acute modifications of HR and inotropy?
Baroreceptors.
When does the majority of ventricular filling occur?
EARLY diastole. This is because of the huge initial pressure gradient.
T or F:
Coronary plaque lesions are often < 50% following AMI.
True.
This indicates that the most important factors of AMI are plaque rupture, platelet aggregation, and thrombus formation.
How does mitral stenosis sound on auscultation?
MS is heard as an “opening snap” at the beginning of diastole, followed by a mid-diastolic rumble that tapers off in sound, and a final crescendo during atrial systole prior to ventricular contraction.
What is the S3 heart sound?
Ventricular gallop. Classically produced by VOLUME overload. Occurs during the rapid filling phase during early diastole. Occurs because of the tensing of the chordinae tendonae when fluid slams against the mitral valve.
What is the S4 heart sound?
Atrial gallop. Classically produced by PRESSURE overload. Occurs when the atria contract at the end of ventricular diastole. S4 is the sound of the atria contracting into a stiff ventricle.
What is the wall tension equation?
Wall tension = (P x Radius) / Wall thickness
P = Delta P (ie. P1-P2)
What is the oxygen delivery equation?
DO2 = (HR x [EDV x EF]) x ([SaO2 x 1.34 x Hgb] x [PaO2 x 0.0031])
Simplified:
DO2 = CO x CaO2
How many much ATP is produced in the Kreb cycle?
36 ATP.
What is the cardiac index?
CI = CO / TBSA
SVR is highest at the ____.
Distal capillaries.
How do right atrial pressure and CVP differ?
The RA is more compliant the SVC/IVC.
What is normal RAP?
< 5
What is normal RVP?
< 25 / < 5
What is normal LAP?
< 10
What is normal LVP?
< 130 / < 20
For CVP to be nearly identical to RVEDP, three factors need to be present:
I) Tricuspid needs to be functioning properly
II) Compliance of RA needs to be identical to vena cava.
III) An open column needs to be present between vena cava & RV.
Explain why CVP can’t be considered identical to RAP:
The RA is dynamic (ie. with respiration), and there is rarely a point in time where RAP is able to equalize with CVP.
Explain the importance of improving contractility prior to reducing afterload:
Sudden decreases in afterload prior to improvement of contractility may cause a rebound increase in HR.
What is tachyphylaxis?
Rapid decrease in response to a drug following administration.
Aortic regurgitant disease should be managed by:
Increasing HR.
This reduces diastolic regurgitation time into the LV.
Aortic stenotic disease should be managed by:
Increasing EDV and slowing HR.
This facilitates a high LV pressure to promote LV outflow.
What are the four causes of hypoxia?
1) Hypoxic
2) Histotoxic
3) Hypemic
4) Stagnant
What are the five causes of hypoxemia?
1) Low FiO2
2) VQ mismatch
3) Diffusion impairment
4) Hypoventilation
5) Shunt (venous admixture)
What is cardiac steal?
Coronary perfusion following the path of least resistance.
For example: Nitrate vasodilation of the LAD during occlusion of the LCX may shunt blood to the LAD, further reducing perfusion of the LCX.
What components of the DO2 equation are modifiable?
1) Cardiac output
2) Hgb
3) SaO2
4) PaO2 (environmental PO2)
Why is unstable angina disappearing as a diagnosis?
UA is essentially early NSTEMI that has not yet produced detectable troponin.
What are the contraindications of nitrates in the realm of critical care?
1) Cardiogenic shock
2) Fixed occlusive lesion (cardiac steal)
3) Preload dependent AMI (ie. RV MI)
Who needs rescue PCI?
1) Persistent STE that hasn’t decreased by at least 50%.
2) Persistent C/P.
What is the time-frame for rescue PCI?
Preferably within 2 hours. Necessary within 24 hours.
STEMI management includes:
1) DAPT
2) Anticoagulation
3) Reperfusion
What is the preferred P2Y12 inhibitor for primary PCI?
Ticagrelor (180mg) or prasugrel.
If clopidogrel, double the usual dose.
What is the preferred anticoagulant in primary PCI?
UFH (5000U + infusion).
UFH can be reversed and controlled better than GP IIb/IIIa inhibitors.
What is the preferred P2Y12 inhibitor for primary fibrinolysis?
Clopidogrel (Age ≤ 75 300mg; Age > 75 75mg).
What is the preferred anticoagulant in primary fibrinolysis?
UFH (4000U + infusion), because it can be reversed with protamine sulphate.
Enoxaparin is acceptable, but enoxaparin eliminates the opportunity for rescue PCI is required.
What is the MOA of P2Y12 inhibitors?
Irreversible blockade of the P2Y12 component of the ADP receptor on platelet surface.
What is the MOA of ASA?
Irreversibly inhibits COX 1 and COX 2 enzymes, ultimately irreversibly inhibiting formation of thromboxane A2, inhibiting platelet aggregation.