Cardiology Flashcards
Nifedipine and amlodipine
-Block L type Ca channels mosty on smooth muscle of arteris, acts like a nitrate
Verapamil and Diltiazam
-Block cardiac L type Ca channel and leads to decrease ionotropy and slowed conduction at AV node
Hydralazine
- Increase cGMP leading to vasodilation
- Used in malignant HTN and pregnancy
- Often co-administered with beta blockers to prevent reflex tachycardia
Nitroprusside
- Release of nitrate for rapid vasodilation
- Can caues cyanide poisoning, treat with thiosulfate to generate thiocyanide which is less toxic
Fendolopam
- D1 agonist, Increase cAMP causing vasodilation (B2)
- Used in malignant HTN
Nitrates and beta blockers
-Often given together in angina to decrease work of heart. Combined cause decrease in all parameters.
Lipoprotein E
- Mediates uptake by liver
- On all but VLDL
Lipoprotein C
-Cofactor for LPL on HDL, Chylpmicrons, VLDL
A-1
-Esterifies lipids only on HDL
B-48
-Necessary for chylomicron assembly
B-100
-Necessay for LDL uptake
Statins
- Competetive inhibitors of HMGCOA reuctase. Decreased melovenate
- Decrease LDL levesl
- Can cause rhabdomyolysis and liver damage
Niacin
- Mainly increases HDL
- Inhibits lypolysis in adipose tissue leading to increased VLDL secretion (contain apo E and can become HDL)
- Flushing is most common S/E (Give aspirin)
- Hyperglycemia and hyperuricemia
Bile Acid binders (Cholestyramine)
- Prevent Bile reabsorption in terminal llleum leading to increased secretion.
- Lowers LDL levels
- Causes GI disturbance, foul taste, and may predispose to cholesterol gal stones
FIbrates
- Decrease triglycerides
- Increase LPL and removes circulating triglycerides
- May cause myostis and hepatic injury
Ezetimibide
-Prevents cholesterol absorption in the gut
Digoxin mechanism and use
- Binds to K binding site of ATPase leading to increased intracellular Na levels and an impaired Na/Ca exchange. Elevated intracellular Ca leads to increased contractility.
- Also has stimulatory effects on vagus leading to block at AV node and bradychardia
- Use CHF, A FIb (rate control)
DIgoxin S/E
- Hyperkalemia
- Yellowing of vision
- Vagal activit leading to GI distress
- AV block and arryhtmia
- Elevated PR and depressed QT
Digoxin overdose Tx
- fAB to digoxin
- normalize K
- Lidocaine
- Mg
Factors that cause digoxin overdose
-Poor renal function
-hypokalemia
-Quinidine
-
Class I Antiarrythmics
- Na Channel blockers leading to alterations in AP duration, blockage of conduction (phase 0) and increase firing threshold.
- If patient is hyerkalemic will increase toxicity
Quindine, Procainamide, Disopyramdie (Class IA)
- Cause an increase in AP duration leading to longer refractory period
- Used in SVT ectopic and re-entry rythms
- Toxicity is Torsades because of longer QT interval
- Quinidine Specifically has Tinnitus and Headaches
- Procaianamide has reversible lupus like syndrome (Hydralazine)
- Disopyramide can cause heart failure
Lidocaine, Tocanide, mexiletene, phenytoin (Class IB)
- Decrease AP duration and refracractory period, especially in damaged tissues
- Used to prevent Arrythmia post MI and Digoxin overdose
Flecainide, Propafenone (class IC)
- Rarely used except if others have failed
- Can cause torsades and other arryhtmias, contraindicated post MI
Beta Blockers (Class 2)
-Decrease cAMP intracellularly leading to decreased contractility, decreased slope of phase 4 and decreased HR
-Used as rate control in SVT and ventricular arrythmias
-Strongest at AV node and cause a prolonged PR interval
Tox: Sedation, may exacerbate asthma, exercise intolerance, impotence, masks hypoglycemia
-Overdose Tx with glucagon. Increase intracellular cAMP
-Esmolol has short half life
-
Amiodarone, Sotalol, Dofetilitide (Class III)
- Block K channels leading to elongated refractory period
- Generally used if others have failed
- All can cause torsades
Amiodarone
- Has properties of all types of anti-arrythmics (structurally similair to thyroid hormone)
- Commonly given if conventional have failed
- Tox: Pulmonary fibrosis, hyper or hypothyroidism, Corneal and skin deposits, Bradycardia, constipation, hepatotox
Verapamil and Diltiazem (Class 4)
- Decrease contractility and conduction velocity
- Increase refrctory period and PR interval
- Most commonly used as rate control in nodal arryhmias, similar to beta blockers
- Tox: AV nodal block, flushing, constipation, hypotension, etc
Adenosine
- Causes K efflux from cardiomyocytes leading to hyperpolarization and abolish of rythm
- Abolishes SVT, makes heart stop
- Effects blocked by caffeine/theophyline
- Short acting, 15 seconds
- Tox: Flushing, hypotension, chest pain
Mg
Used to treat torsades and Siezures of eclampsia
-Similiar structurally to K
