Cardiology Flashcards
what is angina?
chest pain/discomfort arising from the heart as a result of myocardial ischaemia - usually due to narrowing of lumen of CAD due to atherosclerosis/thrombosis
name 3 types of angina
classic/stable, unstable/crescendo, Prinzmetal’s. decibitus (lying down), nocturnal.
what are the differences between stable and unstable angina
stable angina is induced by effort + relieved by rest. unstable angina occurs at rest - treat as ACS.
what is Prinzmetal’s (variant) angina?
angina that occurs without provocation, usually at rest - due to coronary artery spasm.
what causes angina?
atheroma of coronary arteries leading to myocardial ischaemia
give 5 risk factors for angina
diabetes, smoking, hyperlipidaema, hypertension, family history, lack of exercise
list the differential diagnoses of central chest pain
angina, ACS, pericarditis, myocarditis, aortic dissection, massive PE, musculoskeletal, GORD
describe the presentation of angina
central, crushing, retrosternal chest pain - comes on with exertion, relieved by rest. may radiate to arms and neck
list some things that can exacerbate angina
exercise, cold weather, anger, excitement, heavy meals
give some clinical features, apart from pain, of angina
dyspnoea, nausea, sweating, faintess
what investigations would you carry out on a patient with angina? what would you find?
12 lead ECG - shows ischaemic changes at exercise stress test - FBC, glucose, LFT (pre-statin), U&E (renal func), TFT, lipids
functional scans - MRI perfusion scan etc.
how would you manage stable angina?
refer all suspected angina to rapid access chest pain clinic - within 2wks, for confirmation of Dx and severity assessment. - modify risk factors, patient education. - secondary prevention - aspirin 75mg or clopidogril, statins, treat HTN. - symptomatic treatment - GTN spray (and rest!) - first line = beta blockers (atenolol - low HR/BP, cold hands/feet, fatigue) or CCB (diltiazem/verapamil/amlodipine - ankle swelling, flushing) - second line = combo (must be dihydropyridine - if intolerant/CI - long acting nitrate or nicorandil or ivabradine.
how does aspirin work as a method of secondary prevention in angina?
inhibits COX2 and formation of thromboxane A2 - a platelet aggregating agent. reduces risk of coronary events.
name an alternative to aspirin in secondary prevention of coronary events.
clopidogrel
give some examples of beta-blockers
bisoprolol, atenolol, propranolol, metoprolol
describe the mechanism of action of beta blockers in improving symptoms of angina
by acting on beta1 receptors in the heart, they reduce the force of contraction and speed of conduction in the heart - relieves myocardial ischaemia by reducing cardiac work and oxygen demand
what is the major contra-indication of beta-blockers? why?
asthma - beta blockers also act on beta2-receptors which are found in the smooth muscles of airways - cause bronchoconstriction!
give some examples of calcium channel blockers
diltiazem, amlodipine, nifedipine, verapamil
describe the mechanism of action of calcium channel blockers in controlling symptoms of stable angina
they decrease calcium entry into vascular and cardiac cells. they reduce myocardial contractility and suppress cardiac conduction - reduce heart rate, contractility and afterload - reduces myocardial oxygen demand - prevents angina.
what are the major side effects of calcium channel blockers?
postural hypotension/dizziness, headache, ankle oedema - due to systemic vasodilation
describe the mechanism of action of short-acting (GTN) nitrates and long-acting nitrates in acute angina
Nitrates are converted to NO, which increases cGMP and reduces intracellular calcium in vascular smooth muscle cells - vasodilation of venous capacitance vessels reduces preload and LV filling. reduced cardiac work and myocardial oxygen demand - relieve angina
what interventions may be used in worsening angina, not resolved with drugs?
Percutaneous coronary intervention (PCI) - balloon used to dilate atheromatous arteries (stents can be placed) - via catheter. Coronary artery bypass grafting (CABG)
what is involved in a coronary artery bypass graft (CABG)?
internal mammary artery used to bypass stenosis in the LAD or RCA.
what does the term acute coronary syndromes (ACS) include?
unstable angina. NSTEMI. STEMI.