2- Cardiovascular II Flashcards
At therapeutic doses, CCBs act selectively on:
Peripheral arterioles
Arterioles and arteries of the heart
THEY DO NOT EFFECT VEINS
Calcium channels in the myocardium, SA node, and AV node are activated by:
Beta 1 receptors
How do the actions of CCBs and Beta Blockers on the heart differ?
They don’t! They’re targeting the exact same thing
CCBs are stopping calcium channels from responding to Beta 1 activation
Beta blockers are preventing that activation from taking place to begin with
What are the three big actions of CCBs?
Negative Inotrope
Negative Chronotrope
Decreases AV conduction
What is the MOA of Verapamil?
Nondihydropyridine CCB: in blood vessels AND the heart
What is the MOA of Nifedepine?
Dihydropyridine CCB: Acts primarily on arterioles and NOT the heart
What are the five actions of Verapamil?
- Arteriole Blockade: Decreased BP
- Coronary artery dilation: improved coronary perfusion
- SA Blockade: Reduced Heart Rate
- AV blockade: Decreased conduction. MOST IMPORTANT ONE.
- Myocardial blockade: decreased contractility
What is the net effect of verapamil? Why?
Verapamil triggers baroreceptor reflexes, which tends to neutralize the HR, Conduction, and contractility effects
The only thing that dramatically changes, then, is vasodilation and increased coronary perfusion
When is Verapamil used?
Angina
Essential HTN
Cardiac Dysrhythmias
Which patients should never receive Verapamil?
Patients with sick sinus syndrome or 2nd or 3rd degree block
What is the MOA of Diltiazem?
Nondihydropyridine CCB: Same as Verapamil
CCs in the heart AND vessels
What is the MOA of Nifedipine?
Dihydropyridine: Blocks CCs in VSM but NOT in the heart
Which drug will most likely increase a patient’s heart rate: Diltiazem or Nifedipine?
Nifedipine
Both of them trigger reflex tachycardia from vasodilation, but only Diltiazem has cardio-suppressive effects. In the case of Nifedipine, that reflex tachycardia is unopposed
If you give Nifedipine as a slow release, really isn’t a problem
How do the MOAs of Hydralazine and Nipride differ?
Hydralazine selectively dilates arterioles
Nipride dilates arterioles and veins
What is the underlying cause of orthostatic hypotension?
VENOdilation
Does hydralazine cause postural hypotension?
Not so much, because it ONLY EFFECTS ARTERIES
If a patient presents with essential hypertension and no compelling indications, what is the first line drug?
A Thiazide Diuretic
Why would you want to combine a vasodilator with a beta blocker?
You can negate the reflex tachycardia caused by the vasodilator with the beta blocker
In addition to salt and water retention, why is RAAS activation so deleterious in heart failure?
It promotes remodeling and fibrosis, impairing pumping and increasing the probability of dysrhythmias
Activates the SNS and inhibits NE uptake in the heart
promotes vascular fibrosis
Promotes baroreceptor dysfunction
Aldosterone Antagonists have one major AE:
Hyperkalemia
Benefits of Digoxin include:
symptomatic relief
NOT A FIRST LINE AGENT
What is the MOA for digoxin?
Inhibits Na-K ATPase, promoting calcium accumulation within myocytes
the calcium augments contractile force
What is the relationship between potassium levels and digoxin effect?
Potassium competes with dig for binding
It potassium levels are low, dig is hyperactive
If potassium levels are high, dig is hypoactive
Patients with HF signs and symptoms should not take which three drugs? Why?
Antidysrhythmics - have cardiosuppressant and prodysrhythmic actions that can worsen HF
CCBs: Can make HF worse EXCEPT Norvasc
NSAIDs: promote sodium retention and peripheral vasoconstriction
The cardiac effects of Beta blockers are nearly identical to:
the effects of CCBs
Class I Antidysrhythmics are:
Sodium Channel Blockers
Slow impulse conduction in the SA, AV, and Purkinjes
Class II Antidysrhythmics are:
Beta Blockers
Class III antidysrhythmics are:
Potassium Channel Blockers
Class IV Antidysrhythmics are:
CCBs
Class 1B
Prototype
MOA
Lidocaine
Accelerates Repolarization
Amiodarone carries a black box warning for:
Pulmonary Toxicity
AND
Liver Toxicity
CLASS III
Prototype
MOA
Potassium Channel Blockers
Amiodarone
Delays repolarization of rapid action potentials
How will potassium channel blockers alter the ECG?
They prolong repolarization, so they’ll prolong the QT
Only to calcium channel blockers are able to block Ca channels in the heart:
Verapamil
Diltiazem
Blockade of calcium channels in the heart has three effects:
- Slowing of SA node automaticity
- Delay of AV conduction
- Reduced contractility
CCBs are not indicated for:
ventricular dysrhythmias
They only effect the SA and AV conduction
Moderate cardiac atherosclerotic disease usually first manifests as:
Angina
What is the function of lipoproteins in the body>
Binding to fats (which are insoluble) and transporting them in the blood
What is the role of LDLs in the body?
delivering cholesterol to non-hepatic tissues
Which lipoprotein makes the greatest contribution to coronary artery disease?
LDLs
For every 1% drop in LDL levels, the risk for ACS reduces 1%
What is the function of HDLs in the body?
Take cholesterol from the peripheral tissues and return it to the liver
Promote cholesterol Removal!
Why is it so problematic to have high levels of LDLs?
The real problems arise when LDLs enter the subendothelium and become oxidized
Once oxidized, they:
- Attract monocytes, which morph into macrophages
- Inhibit macrophage mobility, thereby trapping them at the site of atherogenesis
- Undergo uptake by macrophages (which only eat oxidized LDLs)
- Damage the vascular endothelium, as they are cytotoxic
What happens when macrophages ingest oxidized LDLs?
They become foam cells: contain large vacuoles filled with cholesterol
They accumulate beneath the arterial epithelium and form a fatty streak
Which is more likely: having an infarction develop at the site of a mature lesion or an immature one?
An immature one
Once the fibrous cap is well established, it’s unusual for a thrombus to develop
Atherosclerosis involves cholesterol, but it is primarily a ________ disease
chronic inflammatory
Is diabetes a risk factor for developing atherosclerotic disease?
No, it is considered a risk equivalent
If you have diabetes, it doesn’t matter if you have or do not have risk factors. You are automatically considered at risk for having a heart attack due to atherosclerotic disease
What are the four behavior modifications proven to reduce LDLs?
Diet
Exercise
Weight Control
Smoking Cessation
Metabolic Syndrome Includes:
Three or more of the following:
- High TG levels
- Low HDL levels
- Hyperglycemia
- Hypertension
- Waist circumference
What is the other name for Statins?
HMG-CoA Reductase Inhibitors
Aside from balancing cholesterol and TG levels, what are the positive benefits of Statins?
- Reduce inflammation at plaque sites
- Stabilize existing plaque sites
- Inhibit platelet deposition and aggregation
- Suppress production of thrombin
What is the MOA of statins?
- Inhibit synthesis of new LDLs by inhibiting HMG-CoA Reductase (the rate limiting enzyme in LDL production)
- Increase the number of LDL receptors on hepatocytes, making the liver more capable of breaking down cholesterol
What are the therapeutic uses of statins?
- Hypercholesterolemia (obviously)
- Prevention of CV events (both in people who have and have not yet had an event)
- Primary prevention in people with normal LDL levels but increased risk
- Post-MI
- Diabetes (controlling CV risk factors is just as important as controlling high BG!)
Statins are primarily excreted by:
the liver, into the bile
What are the major adverse effects of Statins?
- Myopathy and Rhabdomyolysis
- Hepatotoxicity
- New-onset diabetes
What should be done if a statin is causing myalgia?
Replacing Vitamin D
Switching Statins
Coenzyme Q10
Which patients with impaired liver function can take statins?
Patients with viral or alcoholic hepatitis CANNOT
Patients with NASH CAN and SHOULD (they actually help halt the disease process)
Which statins are preferred with renal disease?
Atorvastatin and Fluvastatin
If you need to start a statin in an Asian patient, what should you keep in mind?
Will probably need a lower dose, especially with Rosuvastatin
Start with the lowest available dosage and monitor closely
Which drugs are used as adjuncts to statins when therapy is insufficient with a statin alone?
Bile acid sequestrants
For which patient populations do the risk of statins far outweigh the benefits
Hepatitis and Pregnancy
What is the prototypical bile acid sequestrant?
Ezetimibe
If you see a drug that ends in -cumab, you should think:
monoclonal antibody