Ischaemic Heart Disease Flashcards
How does IHD manifest?
Angina or Myocardial Infarction
What is the most common cause of IHD?
Impaired blood flow/thromboembolic occlusion
Due to atherosclerosis w/i coronary artery
What are the non-modifiable risk factors for IHD?
Male gender
Family history
What are the modifiable risk factors for IHD?
Smoking Diabetes Hypercholesterolaemia Hypertension Sedentary lifestyle Obesity
What are the two classifications of Angina Pectoris?
Stable
Unstable
Describe stable angina
Atherosclerotic disease limiting the heart’s ability to respond to increased demand
Symptoms on exertion, relieved by rest
Describe unstable angina
Generally due to plaque rupture, formation of non-occlusive thromboembolism or vasospasm (Prinzmetal)
Symptoms at rest
What is angina diagnosis based on?
History
ECG
Angiography revealing stenosis
What is the defining characteristic of ischaemic present on an ECG?
ST-segment depression
How is angina managed non-pharmacologically?
Lifestyle advice (smoking, exercise, diet, weight reduction) Coronary artery bypass grafting (CABG) Angioplasty w/ stenting
How does angioplasty w/ stenting work?
Balloon catheter dilates/destroys stenosis
Intraluminal stent prevents restenosis
How is angina managed pharmacologically?
Nitrates - release of NO
NO causes venodilation AND coronary vasodilation
What clases of drugs can be used for the prevention of IHD?
1 - Beta-Blockers
2 - Calcium Channel Blocker
Refractory disease - Beta-Blocker + DHP
How are Beta-Blockers used for the prevention of IHD?
-ve inotropic and chronotropic effects reduce cardiac work
Slowing heart increases diastolic period (coronary flow)
Anti-arrhythmic effects AND reduced risk of MI
How are Calcium Channel Blockers used for the prevention of IHD?
Vasodilation
Improved coronary blood flow
Verapamil/Diltiazem also myocardial depressant/bradycardic
Verapamil also anti-arrhythmic
Do ACEIs have any value in IHD?
Ramipril shown to reduce mortality
How are Potassium Channel Activators used for the prevention of IHD?
Target ATP-sensitive K+ channel - leads to hyperpolarisation
What is Nicorandil?
A combined NO donor and kATP activator
What antiplatelet drugs are available for treating IHD?
Low dose aspirin
Clopidogrel
How does low dose aspirin work?
Inhibits endothelial AND platelet COX
Favours prostacyclin production (decreased thromboxane)
What are the effects of Prostacyclin and Thromboxane?
Prostacyclin - Vasodilator
Thromboxane - Vasoconstrictor AND platelet aggregator
Which type of cells can regenerate COX?
Endothelial cells (nucleated) NOT platelets
What drug may oppose the beneficial effects of low dose aspirin?
Ibuprofen
How does clopidogrel work?
ADP receptor antagonist (preventing platelet aggregation)
When is clopidogrel used?
In patients who cannot receive aspirin
Equally effective
What is the ideal treatment regimen for angina?
Low dose aspirin AND/OR clopidogrel
BP controlled to <140/85
Hypercholesterolaemia to <5mmol (LDL<3)
GTN spray (symptomatic relief)
What drug should be added when treating unstable angina?
Low molecular weight heparin
