Cardiac Ischemia Flashcards
How does dilation of veins/decreasing prelaod affect heart blood flow
Less Oxygen consumption and improved myocardial perfusion
How does dillation of the arteries/decreasing afterload affect the heart
Decrease leads to lower Oxygen consumption
Two broad strategies utilized to improve myocardial ischemia?
Agents increasing O2 supply and agents decreasing O2 demand
Examples of agents that increase O2 supply to heart
Vasodilators (like Ca entry blockers), Statins, Antithrombotics
Examples of agents that help decrease heart O2 demand
Beta blockers
Organic Nitrates
Ca entry blockers
Agents used to treat Stable and Variant Angina
Organic Nitrates
calcium Channel Blockers
Beta-Blockers
Primary effect of organic nitrates in Angina
Marked dilation of veins
How can Organic Nitrate resistance be avoided?
Brief periods (several hours) without the drug
How do Calcium channel blockers help with angina?
Decreased Ca diminishes trigger for contraction
Dilation of arteries, decrease in afterload
What is the role of beta-blockers in Angina
Block epinephrine stimulation of the myocardium
Negative inotropic and chronotropic effect
Lower HR increases Perfusion
OVERALL – Lower Oxygen demand
SA and aV nodal automaticity is caused by…
HCN2/4 channels
HR is increased by…
Hypokalemia Beta agonists Fiber stretch Acidosis Injury
How do beta adrenergic antagonists slow the HR
Inhibit HCN conductance, hyperpolarizing the membrane
Small molecule used to modify HCN?
Ivabradine (Procoralan)
How does Ivabradine work?
Selective blocker of HCN
Approved for patients WHO CAN’T take beta-blockers
What combination therapy is particularly effective in stable angina?
Organic Nitrates + Beta adrenergic antagonists
Combination therapy used for stable angina refractory of organic nitrate/beta-blocker combination
Calcium channel blockers + beta blockers
Which CCB should you use?
Use DHP because it doesn’t inhibit the heart
Combination used for severe vasospastic or stable angina, but NOT for angina+HF
CCB + Organic Nitrates
What to try if none of the double therapies work?
Triple therapy. Bitch.
Beta blocker, Nitrates, Diltiazem, DHPs, Verapamil.
Who causes hypotension, flushing, headaches?
Nitrates and DHPs
Beta blocker, Nitrates, Diltiazem, DHPs, Verapamil.
Who causes LV dysfunction
beta blockers, Verapamil, Diltiazem
Beta blocker, Nitrates, Diltiazem, DHPs, Verapamil.
Who causes major Brady + AV block
beta blocker ad Verapamil
Beta blocker, Nitrates, Diltiazem, DHPs, Verapamil.
Which is heavily associated with GI distress?
Verapamil
Beta blocker, Nitrates, Diltiazem, DHPs, Verapamil.
Which one is a bronchoconstrictor
beta blockers
Effect of Ranolazine?
Inhibits late Na current
Typically in Cardiac Ischemia, the late Na current would lead to Na overload. This would trigger Ca overload. Elevated Calcium would trigger mechanical and electrical disruptions.
What is Ranolazine used for?
To prevent anginal attacks
NOT to terminate currently active ones
Risks of Ranolazine?
Can cause Dizziness
May cause lengthening of QT interval
Three factors that promote plaque instability
Large Lipid Pool
Thin Fibrous Cap
Inflammation
List some strategies to stabilize lipid plaques
Reduce LDL, Increase HDL
Inhibit MMPs, Inflammation
Inhibit Cholesterol crystallization
Two drugs that are used in stents
Paclitaxel
Sirolimus
What is Paclitaxel
Stent drug that binds microtubules and stablizes polymerization
What is sirolimus?
A stent drug macrolide that binds FKB12 and inhibits mTOR to stop cell cycle progression.
Net effect of stent drugs?
Present restenosis by inhibiting smooth muscle cell proliferation
