CAD/Angina Flashcards
Systolic Injury Current
Why are ischemic cells more negative?
What phases does it occur in?
What direction does current flow?
Systolic Injury Current
1) ischemic cells have shorter AP
2) phases 2 & 3
3) positive current flows from normal to ischemic area
During pharmacological stress testing, how does Dobutamine increase contractility/HR?
How do Adenosine/Dipyridamole influence coronary arteries? What risk do they carry?
Dobutamine: stimulate beta1 receptors
Adenosine: coronary vasodilator
Dipyridamole: inhibits adenosine degradation
Since less stenotic arteries will be more responsive, there is the risk of coronary steal.
Name the 7 anti-platelet agents (A, 2C, D, P, 2T)
Aspirin Clopidogrel Cilostazol Dipyridamole Prasugrel Ticlopidine Ticagrelor
How does aspirin inhibit platelet aggregation?
In what 3 groups of patients is aspirin used to reduce the risk of adverse CV events?
Irreversible COX inhibitor –> inhibit TXA2 prod
stable angina, unstable angina, acute MI
Ticlopidine is an anti-thrombotic that is an alternative to aspirin. It reduces blood viscosity by decreasing plasma fibrinogen, and increases RBC deformability.
How else does it work?
What 2 side effects does it have?
inhibits ADP-induced platelet aggregation
neutropenia, TTP (rare)
Is Clopidogrel’s anti-thrombotic effect greater or lesser than Ticlopidine?
How does Clopidogrel block activation of the 2b/3a complex?
stronger anti-thrombotic
selectively/irreversibly inhibit ADP binding to its platelet receptors
Prasugrel reduces thrombotic events in what patients?
What ADP GPCR does it irreversibly bind to?
Patients during ACS who have received PCI.
Prasugrel irreversibly binds to the P2Y12 receptor.
Prasugrel is a more potent anti-platelet agent than Clopidogrel, but it carries a higher risk of bleeding. So it is limited to what patient population?
Limited to patients 60kg with no Hx of stroke or TIA
Describe Ticagrelor’s mechanism of action.
Why does Ticagrelor have a fast onset of action compared to Clopidogrel/Prasugrel?
Reversible blockade of ADP receptors at a binding site different from ADP
It does not require hepatic activation.
Compare Ticagrelor to Clopidogrel in terms of efficacy and bleeding risk in patients with ACS?
Ticagrelor: more potent anti thrombotic, but a higher risk of bleeding
Dipyridamole increases platelet intracellular cAMP. How does this effect PDE, AC, and adenosine uptake from vascular endothelium and RBCs?
Dipyridamole –> increase cAMP
- -inhibit PDE
- -activate AC
- -inhibit adenosine uptake
How is Dipyridamole used?
It is rarely used due to what side effect?
Therapy
- -adjunct for treating peripheral vascular disease
- -stress test of heart
Side Effect
–coronary artery vasodilation can enhance exercise-induced ischemia
How does Cilostazol inhibit platelet aggregation?
What is it’s therapeutic use?
What side effect limits its use, especially in HF patients?
inhibit PDE –> increase cAMP
Treats claudication in peripheral vasc disease
Causes vasodilation, which may increase M&M in HF patients
Name the 6 ACE inhibitors, which all end in -pril.
CELFRQ
Captopril Enalapril Lisinopril Fosinopril Ramipril Quinapril
Describe the mechanism of action for how ACE inhibitors lower BP?
inhibit ACE –> block Ang2 formation –> prevent Ang2 mediated vasoconstriction & Na/H2O retention