Manifestation of Myocardial Ischaemia

Question 1

When does coronary artery blood flow occur?

Answer 1

Diastole

Question 2

What is a ‘respiratory’ differential diagnosis for a patient with chest pain?

Answer 2

Respiratory = pneumonia (temp, cough, breathless), pulmonary embolism (asymptomatic, breathless, sharp/localised pain worse on inspiration).

Question 3

What is a ‘cardiac’ differential diagnosis for a patient with chest pain?

Answer 3

Cardiac (muscles/pericardial sac)= ischaemic (dull, retrosternal, central, radiate to jaw/neck/shoulders), pericarditis (sharp, retrosternal, eased with sitting up/leaning forward).

Question 4

What is a ‘GI’ differential diagnosis for a patient with chest pain?

Answer 4

GI = reflux (burnin, worse on lying flat/eating).

Question 5

What is a ‘MSK’ differential diagnosis for a patient with chest pain?

Answer 5

MSK = rib fracture, costochondritis (sharp, localised, tender, worse with movement)

Question 6

What is the difference between somatic and visceral pain?

Answer 6

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.

Question 7

When does heart tissue ischaemia occur?

Answer 7

Only when the metabolic demands of cardiac muscle are greater than what can be delivered via coronary arteries

Question 8

Describe the risk factors for coronary atheroma

Answer 8

Male, age, genetics, smoking, hypertension, hypercholesterolaemia, DM, obesity, sedentary lifestyle

Question 9

Describe the pathophysiology of stable angina

Answer 9

Coronary artery stenosis = stable atherosclerotic plaque – no rupturing. Spams of coronary artery. Anaemia. Severe aortic valve stenosis.

Question 10

Describe the pathophysiology of unstable angina

Answer 10

Atherosclerotic coronary artery disease, ruptures, platelet aggregation, thrombus, acute occlusion

Question 11

Describe the pathophysiology of myocardial infarction

Answer 11

Complete/near complete occlusion of coronary artery by ruptured atherosclerotic plaque with thrombus formation

Question 12

What are the clinical features of stable angina?

Answer 12

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

Question 13

What are the clinical features of unstable angina?

Answer 13

Pain at rest, pain may be more intense, pain may last longer

Question 14

What are the clinical features of myocardial infarction?

Answer 14

Dull retrosternal chest pain >15mins, radiate to neck/shoulder/jaw, look unwell, chest pain at rest, increased autonomic output (sweaty, anxious, pallor, nauseous)

Question 15

How is stable angina treated?

Answer 15

Aspirin, beta blockers, stain, ACE inhibitors, oral nitrate, nicorandil, CCB, PCI: balloon/stent angioplasty, CABG: coronary artery bypass surgery

Question 16

How is unstable angina treated?

Answer 16

Optimise general condition, pharmacological, reperfusion: PCI, CABG

Question 17

How is myocardial infarction treated?

Answer 17

Oxygen, pain relief, GTN sublingually, aspirin, reperfusion

Question 18

What characteristic distinguishes unstable angina from stable angina

Answer 18

Unstable = pain at rest

Question 19

What is ‘Acute Coronary Syndrome’?

Answer 19

Atherosclerotic coronary artery disease, ruptures, platelet aggregation, thrombus, acute occlusion = unstable angina, MI, NSTEMI, STEMI

Question 20

Explain the difference between unstable angina, NSTEMI and STEMI

Answer 20

Unstable angina = ischaemia = no enzymes leak. NSTEMI/STEMI = infarct = cardiac enzymes leak

Question 21

Describe the investigations for myocardial infarction

Answer 21

ECG, blood tests: troponin

Question 22

Describe the use of the ECG in the diagnosis of MI, distinguishing STEMI from a NSTEMI

Answer 22

STEMI = ST elevation, hyperacute T waves. NSTEMI = ST depression, T wave flattening/inversion

Question 23

Describe the use of cardiac biomarkers as a marker for MI

Answer 23

Troponin indicates cardiac myocyte death

Question 24

How do biomarkers distinguish between NSTEMI and unstable angina?

Answer 24

Troponin release in NSTEMI = infarct tissue death

Question 25

Outline the investigations for stable angina

Answer 25

FBC, cholesterol, U+Es, TFT, ECG, chest x-ray (might see cardiomegaly), test for ischaemia = treadmill test, dobutamine stress test

Question 26

What surgical treatments can be used in coronary artery disease?

Answer 26

PCI (percutaneous coronary intervention) balloon/stent angioplasty

CABG: coronary artery bypass surgery

Question 27

Describe the signs and symptoms of acute pericarditis

Answer 27

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)

Question 28

Other than MI, in what cardiac conditions is troponin released?

Answer 28

severe stenosis,

myocarditis,

prolonged tachycardia,

defibrillation by CPR,

aortic dissection,

acute heart failure

Question 29

In what non-cardiac conditions is troponin released?

Answer 29

Acute PE, pulmonary hypertension, haemodynamic challenge, sepsis, COPD, severe anaemia, polymyositis, seizures, kidney failure

Question 30

How does ischaemia present on ECG?

Answer 30

ST segment depression, flat T waves