Ischaemic Heart Disease and its Consequences

Question 1

Epicardial

Answer 1

outer surface of heart

Question 2

Endocardial

Answer 2

inner surface of heart

Question 3

Subendocardial region

Answer 3

water-shed area of perfusion and first to become ischaemic

Question 4

Coronary Artery Imaging in humans in life

Answer 4

• Coronary Angiography • CT

* MR imaging

Question 5

Causes:

Answer 5

Chronic coronary insufficiency:
Angina

Unstable coronary disease:
Myocardial infarction
Sudden ischaemic coronary death

Heart Failure

Arrhythmia:
acute Ischaemia
Scar related

Question 6

Atherosclerotic Coronary Artery Disease risk factors

Answer 6

Age
Hypertension Hypercholesterolaemia Smoking
Diabetes
Obesity
Physical inactivity

Question 7

Atherosclerotic Coronary Artery Disease

Pathology- the three components

Answer 7

• fatty streak
• fibro-fatty plaque
• plaque disruption (plaque rupture or erosion)

Question 8

symptoms of angina

Answer 8

– Gripping central chest pain
– Radiation to arm and jaw
– Clear and precise relationship to exercise
– Goes off in 2-10 mins after discontinuation of exercise – Worse after food. Worse in cold
– No autonomic features
– Flat of hand/fist to describe pain

Question 9

cause of angina

Answer 9

– Sub-Endocardial ischaemia

Question 10

how does angina present on an ECG

Answer 10

ST depression

Question 11

angina mechanism

Answer 11

MISMATCH OF BLOOD SUPPLY TO DEMAND BECAUSE OF EPICARDIAL STENOSIS:
Supply = Coronary Blood Flow
Demand = Myocardial Oxygen Consumption
(MVO2 )

Question 12

• Two regulatory systems with two control mechanisms

Answer 12

– Autoregulation (myogenic control)

– Metabolic regulation

Question 13

determinants of myocardial oxygen consumption

Answer 13

- variable per unit mass of tissue:
tension development – LV pressure and LV volume Contractility
Heart rate
- fixed per unit mass of tissue:
basal activity (10-20%)
- Mass of tissue

Question 14

Identification of Coronary Disease as the cause: anatomical assessment

Answer 14

– CT coronary angiography

– Invasive angiography

Question 15

Identification of Coronary Disease as the cause: Test of Inducible ischaemia

Answer 15

– Exercise stress test
– Dobutamine stress echo
– Myocardial perfusion imaging with either exercise or phamacological stress
– Cardiac magnetic resonance imaging (cMR)

Question 16

Identification of Coronary Disease as the cause: anatomic and functional

Answer 16

– Invasive angiography and fractional flow reserve (FFR)
– cMR
– Novel CT

Question 17

Angina Treatment - Reduce Myocardial Oxygen consumption.

Answer 17

drugs

Question 18

Angina Treatment - improve coronary flow reserve

Answer 18

– Percutaneous Coronary Intervention (stents and balloons)

– Coronary Artery Bypass Grafting (CABG) – Drugs - Vasodilators

Question 19

Drug treatment and Angina

Answer 19

1. Reduction in myocardial oxygen consumption

2. Reduction in the variability of coronary flow reserve

Question 20

Beta Adrenoceptor Blockers

Answer 20

– Reduce Heart Rate, Reduce Blood Pressure

– i.e. Reduce work of heart

Question 21

• Nitrates(GTN)

Answer 21

– Venodilation → Reduced LV size → Wall tension. (reduces work) Small effect on epicardial stenosis dilation (improved supply)

Question 22

• Calcium Channel blockers

Answer 22

– Reduce HR, some reduce Heart rate, small effect on from epicardial dilatation (mixed)

Question 23

• Ikf Channel Inhibitors

Answer 23

– Selective heart rate reduction by inhibiting channels in SA node - Ivabridine

Question 24

MYOCARDIAL INFARCTION – Clinical Presentation

Answer 24

• chest pain, severe, crushing radiating to jaw and arm
• associated ‘autonomic’ symptoms (nausea, sweating, terror)
• breathlessness

Question 25

events modifying presentation of AMI

Answer 25

- time of day - inflammatory activity - infection esp. respiratory - elevation of BP - catecholamines

Question 26

Classifications of Myocardial Infarction - by site of infarction, pathology

Answer 26

– Full thickness, transmural | – Sub endocardial

Question 27

Classifications of Myocardial Infarction - By ECG - Clinical

Answer 27

– ST Elevation myocardial infarction (STEMI) | – Non-ST elevation myocardial infarction (non- STEMI)

Question 28

Classifications of Myocardial Infarction - By cause

Answer 28

– Type 1-4

Question 29

Relation between anatomy and ECG

Answer 29

* STEMI implies transmural myocardial infraction | * NSTEMI will include subendocardial infraction but does not exclude transmural infraction in regions remote from ECG

Question 30

• A Clinical History with: | – ECGChanges,definingsub-classificationof:

Answer 30

* STEMI | * NSTEMI

Question 31

ECG Changes, defining sub-classification of: And raised cardiomyocyte markers in blood

Answer 31

* Troponin T or I * Creatine kinase MB isoform (CKMB) * Creatine Phosphokinase (CPK) * AST * Myoglobin

Question 32

STEMI Management

Answer 32

Antiplatelet agents: Aspirin + Clopidogrel or other antiplatelet (P2Y12 inbibitor) Immediate revascularisation: Primary PCI (Thrombolysis – clot busting)

Question 33

Adjunctive Therapy for STEMI: • After anti-platelets agents and revascularisation

Answer 33

– Statin drugs (reduce cholesterol – plaque passivation) – ACE inhibitors (usually a couple of days later to inhibit dilation of the left ventricle) – Beta blockers (reduce myocardial infarction)

Question 34

Complications of STEMI - immediate

Answer 34

– Ventricular Arrhythmia and death | – Acute Left Heart Failure

Question 35

Complications of STEMI - Early (Day 2-7)

Answer 35

– Myocardial Rupture – Mitral valve insufficiency – Ventricular Septal defect – Mural thrombus and emobolisation

Question 36

Complications of STEMI Late (beyond day 7)

Answer 36

– LV dilatation and heart failure – Arrhythmia – Recurrent myocardial infarction

Question 37

NSTEMI

Answer 37

• Getting more frequent (STEMI less common) • More common in elderly • Implies sub-endocardial ischaemia • Caused by: – Threatened STEMI – Small branch occlusion – Occlusion of well collateralised vessel – Lateral STEMI in territory not well seen by ECG

Question 38

Treatment of non-STEMI

Answer 38

• Anti platelet therapy (Aspirin and clopidogrel) • Anti-ischaemics(beta blockers and nitrates) • Statin drugs • ACE inhibitors • Coronary angiography and revascularisation – Early if symptoms continue – Early if Troponin raised – Risk score (eg GRACE)