IHD Flashcards
IHD manifests as either … or …
- Angina
- Myocardial infarction
Associated with atherosclerosis within the coronary artery. Impaired Blood flow/ Temoblic occlusion
Non-Modifiable risk factors for IHD
- Male gender
- Family history
Modifiable risk factors for IHD
- Smoking
- Diabetes
- Hypercholesterolaemia
- Hypertension
- Sedentary lifestyle
- Obesity
Two types of anigna
Stable: Atherosclerotic disease, limits hearts ability to respond to demand
- Symptoms on exertion, relieved at rest
Unstable: plaque rupture and non-occlusive thromboembolism, or vasospasm
- Symptoms at rest
Diagnosing IHD
A history/clinical diagnosis
In stable angina:
- Pain induced by exercise, relieved by rest/GTN
ECG: ST segement depression is associated with ischaemia
Coronary artery angiography reveals stenosis
IHD managment
- Lifestyle advice
- CABG most effective approach
- Angioplasty with stenting
Drug classes for IHD management
- Nitrates
- B-Blockers
- Calcium channel blockers
- ACEIs
- Potassium channel activators
- Antiplatelet drugs
Nitrates MOA in IHD
Via release of nitric oxide
- Venodilator, leading to decrease in prpeload and reduction in cardiac work
- Coronary vasodilatation, imporves coronary blood flow
b-Blockers MOA in IHD
- First choice for prevention
- -ve inotropic and chronotropic effects, reducing cardiac work and preventing symptoms
- Coronary flow only occures during diastole then by slowing the heart the diastolic period will be increased, as will the time for coronary blood flow
- Anti-arrhytmic effects and reduces risk of MI
Calcium channel blockers in IHD
- Vasodilatation and improve coronary blood flow, so preventing symptoms.
- Verapamil (and to a lesser extent diltiazem) also have myocardial depressant and bradycardic actions, so reducing cardiac work.
- Verapamil also exerts Class IV anti-arrhythmic activity.
ACEIs in IHD
•HOPE trial indicated that ramipril reduced mortality in patients with IHD
Potassium channel activators in IHD
- Nicorandil: combined NO donor and activator of ATP-sensitive K-channels.
- The target is the ATP-sensitive K+-channel (KATP): … hyperpolarization
Anitplatelet drugs in IHD
Low dose aspirin
- Favours prostacyclin production over thromboxane as inhibits both endothelial and platelet cyclo-oxygenase (COX). Endothelial cell as nucleated and can regenerate COX, platelets lack nuclei and can not
- Ibuprofen may oppose beneficial actions
Clopidogrel
- ADP receptor antagonist (prevents platelet aggregation)
- Equally effective aspirin
- Used in pts who can not receive aspirin (e.g. in asthma)
Drug choice for IHD prevention
1st choice: b-blockers for more pronounced stable and unstable angina
- But not Prinzmetal angina
- Oral long-acting nitrates might be added.
2nd choice: if a b-blocker is ineffective or contra-indicated, then verapamil (or diltiazem) would be used or failing that a long-acting dihydropyridine (DHP).
Calcium channel blockers are particularity effective at reversing vasospasm
- First choice drugs for Prinzmetal angina.
In refractory disease: a b-blocker plus DHP but not with verapamil. Nicorandil might also be added to therapy.
Stable and unstable angina treatment overview
In unstable angina add low molecular weight heparin
