S9: ischaemic heart disease

Question 1

Identify and differentiate between the common causes of chest pain

Answer 1

Cardiac = dull/heavy, crushing, poorly localised, central, worsened with exertion, refers to jaw/neck/arm
Pleuritic = sharp, well-localised, often non-central, worsened with chest movement (breathing in/coughing)

Question 2

Describe the risk factors for coronary atheroma

Answer 2

Modifiable: high cholesterol, smoking, diet, hypertension

Non-modifiable: age, sex, family history

Question 3

Describe the pathophysiology of stable angina, unstable angina and myocardial infarction

Answer 3

Stable occlusion -> plaque rupture (acute) -> thrombus formation -> sudden increased occlusion (acute coronary syndromes) -> severity of occlusion determines the acute coronary syndrome diagnosed

Question 4

Describe the signs and symptoms of angina and distinguish the characteristics of unstable angina from stable angina

Answer 4

Both types are cardiac sounding chest pain & patient may have risk factors associated with atherosclerosis, troponin levels are normal
Stable angina: pain on exertion which is relieved by rest, ECG normal at rest but T wave inversion/ST depression if taken during exercise
Unstable angina: chest pain present at rest, much more severe & longer lasting, on ECG ST depression/T waves changes are seen

Question 5

Describe the signs and symptoms of myocardial infarction

Answer 5

Crushing pain, radiates to jaw/arm
Shortness of breath
Sweating
Nausea/vomiting

Question 6

Understand the concept of ‘Acute Coronary Syndrome’ and explain the difference between unstable angina, NSTEMI and STEMI

Answer 6

Acute coronary syndromes = spectrum of acute myocardial ischaemic events caused by atheromatous plaque rupture with thrombus formation
Causing acute increased occlusion in coronary artery
Leads to ischaemia & potential infarction
In unstable angina, troponin is not raised (no necrosis taken place), whereas in MI troponin I & T levels are raised due to necrosis of cardiac tissue

Question 7

Describe the investigations for myocardial infarction

Answer 7

ECG
Troponin
Echocardiogram
CXR

Question 8

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

Answer 8

STEMI = ST elevation
NSTEMI = ST depression
Both acute changes in the ECG (after days/weeks these changes no longer present)

Question 9

Identify region of the heart affected from the particular groups of leads which show changes in myocardial infarction

Answer 9

Septal = V1, V2
Anterior = V1-V6
Lateral = V5, V6
Anteroseptal = V1-V4
Anterolateral = V3-V6
Inferior = II, III, aVF
High lateral = I, aVL

Question 10

Describe the use of cardiac biomarkers as a marker for MI and to distinguish between NSTEMI & unstable angina in a patients with Acute Coronary Syndrome

Answer 10

To distinguish between NSTEMI and unstable angina, troponin levels should be measured
In NSTEMI, troponin is raised, whereas in unstable angina troponin levels are the same

Question 11

Describe the principles of the management of angina, unstable angina and acute myocardial infarction

Answer 11

Lifestyle changes
Dual antiplatelets for 12 months, then aspirin for life
Statin aiming for total cholesterol < 4mmol/L
ACE inhibitor aiming for BP < 140/80

Question 12

Describe the use of surgical treatments in coronary artery disease

Answer 12

Invasive coronary angiogram = wire the occluded vessel, predilate the narrowed sections with balloons, stent with metal scaffold to keep vessel patent

Question 13

Describe the signs and symptoms of acute pericarditis

Answer 13

Pericarditis = inflammation of the pericardium
Sharp, retrosternal pain, aggravating by breathing in/coughing, eased when leaning forwards
Pericardial rub (on auscultation of heart)
Further investigations: ECG, blood test

Question 14

List which arteries are affected in different MIs

Answer 14

Inferior - right coronary artery
Anterior - left anterior descending artery
Antero-lateral - left circumflex artery