Manifestation of Myocardial Ischaemia Flashcards
When does coronary artery blood flow occur?
Diastole
What is a ‘respiratory’ differential diagnosis for a patient with chest pain?
Respiratory = pneumonia (temp, cough, breathless), pulmonary embolism (asymptomatic, breathless, sharp/localised pain worse on inspiration).
What is a ‘cardiac’ differential diagnosis for a patient with chest pain?
Cardiac (muscles/pericardial sac)= ischaemic (dull, retrosternal, central, radiate to jaw/neck/shoulders), pericarditis (sharp, retrosternal, eased with sitting up/leaning forward).
What is a ‘GI’ differential diagnosis for a patient with chest pain?
GI = reflux (burnin, worse on lying flat/eating).
What is a ‘MSK’ differential diagnosis for a patient with chest pain?
MSK = rib fracture, costochondritis (sharp, localised, tender, worse with movement)
What is the difference between somatic and visceral pain?
Somatic = relating to pleural or pericardial (surface) = sharp, localised, worse with inspiration, or positional movement. Visceral = relating to the lung or heart (organ) = dull, poorly localised, worsening with exertion.
When does heart tissue ischaemia occur?
Only when the metabolic demands of cardiac muscle are greater than what can be delivered via coronary arteries
Describe the risk factors for coronary atheroma
Male, age, genetics, smoking, hypertension, hypercholesterolaemia, DM, obesity, sedentary lifestyle
Describe the pathophysiology of stable angina
Coronary artery stenosis = stable atherosclerotic plaque – no rupturing. Spams of coronary artery. Anaemia. Severe aortic valve stenosis.
Describe the pathophysiology of unstable angina
Atherosclerotic coronary artery disease, ruptures, platelet aggregation, thrombus, acute occlusion
Describe the pathophysiology of myocardial infarction
Complete/near complete occlusion of coronary artery by ruptured atherosclerotic plaque with thrombus formation
What are the clinical features of stable angina?
Stable atherosclerosis = at rest level of blood flow is ok, during exercise blow flow can’t reach demand = dull ‘vice’ retrosternal pain, no chest pain at rest, clinical exam often normal, GTN spray relieves pain
What are the clinical features of unstable angina?
Pain at rest, pain may be more intense, pain may last longer
What are the clinical features of myocardial infarction?
Dull retrosternal chest pain >15mins, radiate to neck/shoulder/jaw, look unwell, chest pain at rest, increased autonomic output (sweaty, anxious, pallor, nauseous)
How is stable angina treated?
Aspirin, beta blockers, stain, ACE inhibitors, oral nitrate, nicorandil, CCB, PCI: balloon/stent angioplasty, CABG: coronary artery bypass surgery
How is unstable angina treated?
Optimise general condition, pharmacological, reperfusion: PCI, CABG
How is myocardial infarction treated?
Oxygen, pain relief, GTN sublingually, aspirin, reperfusion
What characteristic distinguishes unstable angina from stable angina
Unstable = pain at rest
What is ‘Acute Coronary Syndrome’?
Atherosclerotic coronary artery disease, ruptures, platelet aggregation, thrombus, acute occlusion = unstable angina, MI, NSTEMI, STEMI
Explain the difference between unstable angina, NSTEMI and STEMI
Unstable angina = ischaemia = no enzymes leak. NSTEMI/STEMI = infarct = cardiac enzymes leak
Describe the investigations for myocardial infarction
ECG, blood tests: troponin
Describe the use of the ECG in the diagnosis of MI, distinguishing STEMI from a NSTEMI
STEMI = ST elevation, hyperacute T waves. NSTEMI = ST depression, T wave flattening/inversion
Describe the use of cardiac biomarkers as a marker for MI
Troponin indicates cardiac myocyte death
How do biomarkers distinguish between NSTEMI and unstable angina?
Troponin release in NSTEMI = infarct tissue death
Outline the investigations for stable angina
FBC, cholesterol, U+Es, TFT, ECG, chest x-ray (might see cardiomegaly), test for ischaemia = treadmill test, dobutamine stress test
What surgical treatments can be used in coronary artery disease?
PCI (percutaneous coronary intervention) balloon/stent angioplasty
CABG: coronary artery bypass surgery
Describe the signs and symptoms of acute pericarditis
More common in men, sharp central retrosternal pain, pain worse on inspiration/lying flat, eased with sitting up and leaning forward, ausculatation = course sounding (pericardial rub)
Other than MI, in what cardiac conditions is troponin released?
severe stenosis,
myocarditis,
prolonged tachycardia,
defibrillation by CPR,
aortic dissection,
acute heart failure
In what non-cardiac conditions is troponin released?
Acute PE, pulmonary hypertension, haemodynamic challenge, sepsis, COPD, severe anaemia, polymyositis, seizures, kidney failure
How does ischaemia present on ECG?
ST segment depression, flat T waves
