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16 Cards in this Set
- Front
- Back
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What is the major strategy in all forms of angina treatment?
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Reduce myocardial demand for O2.
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List the types of medication used
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Beta blockers
Nitric vasodilators (used acutely) Ivabridine Calcium channel blockers Statins ( |
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How do Beta Blockers decrease myocardial demand for O2?
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By way of Comp Revers Antag of B1 AR
Dec HR and Dec myocardial work |
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List example drugs
What are there side effects |
Propanolol(1&2) atenolol (1)
Exarcerbate Asthma (block of B2) Exercise intolerance Hypoglycaemia blockage may lead to A1 mediated constriction in coronaries |
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How does Ivabridine decrease myocardial demand for O2?
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Blocks I(f) Na+ current that contributes to SA node depolarisation towards threshold
Decreases the Heart rate but not force |
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How does dilation of arteries/veins contribute to decreased o2 demand?
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Arteries: Dec after load
Dec Myocardial work Veins: Decrease Pre-load Venous dilation decreases all of the following: *Venous return *Pre-load *Stretch of ventricle *Strength of contraction *Myocardial work *myocardial O2 Demand |
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List some nitrovasodilators
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Isosorbide mononitrate
Isosorbide dinitrate Glycerl trinitrate Amyl nitrate |
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Explain how glyceryl trinitrate and amyl nitrate are used and why they would be given
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GTN: sublingual spray or tablet (not orally active)
AN: Vial inhaled Uses: Prophylaxis in stable angina (before exercise) Rapid relief of ongoing anginal attacks |
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How are the other Nitrovasodilators given and why?
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ID & IM: taken orally and have a slower onset and more prolonged duration than GTN.
Uses: Sustaining prophylaxis in all forms of angina |
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Describe how nitrovasodilators exert their effect
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Lipophillic=>enter SMCs and are reduced to NO
They mimic the action of endogenous NO NO=> soluble guanylate cyclase SGC contains a ferrous haem on its receptor. No binds this and activated the conversion of GTP to cGMP. This increase in cGMP results in vasodilation |
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Do NVDs work beter on arteries or veins?
Why is this? Any side effects? |
Venous dilation>arterial dilation
Venous dilation decreases pre load=decreases myocardial work headache (cerebral dilation of arteries) Tolerance on prolonged use |
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List some L-type Voltage gated calcium channel blockers.
Outline their effectiveness on Cardiac muscle and smooth muscle |
Verapamil
Nifedipine Diltiazem SMC: Nifedipine>diltiazem>verapamil Cardiac muscle: Verapamil>diltiazem>Nifedipine |
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Describe the the mechanism of Ca blockers
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1) Open channel block (Verapamil and diltiazem)
2) Allosteric modulaion (Nifedipine) - reduce channel opening |
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What are the anti anginal effects of Ca blockers?
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Dilation of arteries (decrease after load)
Decrease HR and Force CAs dilation (good in variant angina, coronary steal in other) |
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Adverse effects of Ca blockers in Anti angina treatment?
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Coronary steal
headache Constipation Extreme overdose -heart block -Cardiac failure |
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What is the algorithm for angina treatment?
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Step 1: GTN plus Beta blocker or Calcium channel blocker
-antiplatelet, lipid lowering, anti-HT Step 2: Beta and Calcium channel blocker Step 3: long acting nitrovasodilator or Ivabridine Step 4: Surgical intervention: Stent/Coronary artery bypass grafting |
