MP323 - ANGINA Flashcards
ischaemia
- insufficiency in blood supply
- coronary artery is the only blood source for the heart
- coronary arteries are blocked, the blood supply to the heart will reduce, which may result in chest pain; angina
angina pectoris (angina)
result of ischaemia caused by an imbalance between myocardial blood supply and oxygen demand
main symptom is chest pain
3 types of pathophysiology of angina
stable
unstable
Prinzmetal’s
unstable angina
- rapidly worsening chest pain on minimal exertion or at rest
- associated with an ulcerated atheroma and thrombus formation. produces a greater reduction of coronary blood flow to produce angina at rest.
stable angina
occurs when coronary perfusion is impaired by fixed or stable atheroma of coronary arteries
Prinzmetal’s angina
coronary artery spasm: sudden involuntary contraction of smooth muscle tissue in coronary artery
usually occurs at rest
spasm temporarily narrows the artery
stable angina classification
- exertional angina
- angina equivalent syndrome
- syndrome-X
- silent ischaemia
- decubitus angina
- nocturnal angina
exertional/classical angina
- arises from an increase in myocardial oxygen demand during exertion or emotion. relief occurs by rest and nitroglycerine
- coronary artery obstructions are not sufficient to result in resting myocardial ischaemia
angina equivalent syndrome
- caused by myocardium ischaemia
- symptoms: shortness of breath, pain at other site than chest (e.g. arm or jaw)
syndrome X
- typical, exertional angina with positive exercise stress test
- reduced capacity of vasodilation in microvasculature
silent ischaemia
- very common
- difficult to diagnose
- Holter monitor
- exercise testing
- people with previous heart attack or diabetes are high risk
decubitus angina
- chest pain occurs only when lying down (relieved by standing or sitting)
- associated with impaired left ventricular function and coronary artery disease
- cause: gravity redistributes fluids in body, makes heart work harder
nocturnal angina
- awakes patient from sleep
- may be provoked by vivid dreams
- may occur due to coronary artery spasm
Holter monitor
- portable device for cardiac monitoring
- monitors for 24 to 72hrs
- check for silent ischaemia
- continuously records ST segments for flat or down-sloping ST depression of 1 to 2 mm or more
stable angina assessment
history: grading scale
exercise testing
electrocardiogram (ECG)
class I of angina severity (4 classes)
angina only during strenuous or prolonged physical activity
class II angina severity (4 classes)
slight limitation with angina only during vigorous physical activity
class III angina (4 classes)
moderation limitation, symptoms with everyday living activities
class IV angina (4 classes)
severe limitation, inability to perform any activity without angina or angina at rest
stable angina - exercise testing
goal is to induced a controlled, temporary ischaemic state during clinical and ECG observation
stable angina - ECG
ST segment depression occurs with ischaemia and reverses after ischaemia disappears
atherosclerotic plaque and thrombus steps
- initial fatty streak
- plaque enlarges
- loss of endothelium and exposure of collagen
- platelet adherence and activation
- fibrin meshwork deposition with RBC entrapment
- more flow turbulence
- thrombus of alternating layers of platelets, fibrin and RBCs
angina symptoms first-line therapy
beta blockers + sublingual GTN
inadequate control of symptoms of angina symptoms after first-line therapy
ADD A CALCIUM CHANNEL BLOCKER
beta blocker + calcium channel blocker + GTN
angina treatment if intolerant of beta blockers
rate-limiting calcium channel blocker, long-acting nitrates or nicorandil
angina symptom treatment if not controlled after drug therapy
refer to cardiologist if not controlled on maximum doses of two drugs
