Chest pain and ischemic heart disease

Question 1

Feeling of typical ischemic chest pain

Answer 1

Heavy/crushing

Question 2

Which area of the heart is most vulnerable to ischemia

Answer 2

Sub-endocardial area

*closest to LV cavity where myocardial wall pressure is greatest and vessels are extra constricted

Question 3

How much must a lumen be occluded to experience angina vs angina at rest?

Answer 3

70%, 90% at rest

Question 4

Why is increased HR or occlusion detrimental to the myocardium?

Answer 4

Diastole is when coronary arteries vasodilate and bloodflow is at its max

*shortened diastole = less time for myocardial perfusion

Question 5

What are collateral vessels and where are they? Why do they develop/expand?

Answer 5

Form perfusion links between smaller arteries and arterioles - develop/expand when myocardium is ischemic and needs extra blood routes

Question 6

What are the 2 components of a plaque

Answer 6

Fibrous cap and necrotic centre

Question 7

Explain how the lumen of an artery would appear in someone with a stable angina

Answer 7

An intact plaque has formed above lipids, occluding the artery about 70%

Question 8

What happens if a plaque inside a vessel breaks?

Answer 8

Blood exposed to thrombogenic substances in necrotic centre -> platelet clot -> thrombi -> potential thromboemboli

Question 9

3 non-modifiable RFs for ischemic heart disease

Answer 9

Non-modifiable: age, male, family history

Question 10

What is the key difference between a stable angina and an Acute coronary syndrome?

Answer 10

Pain is reproducible in stable angina

*typically brought on by same amount of exertion

Question 11

Name the 3 types of Acute coronary syndromes and list them in order of increasing severity:

Answer 11

Unstable Angina, NSTEMI, STEMI

Question 12

What 2 things typically relieve stable angina pain

Answer 12

Rest and/or nitrates

Question 13

4 potential signs a patient with stable angina could have

Answer 13

Higher BP, LV dysfunction, corneal arcus, evidence of atheromas elsewhere, ie peripheral vascular disease

Question 14

What is involved in an invasive CT coronary angiography?

Answer 14

Catheter inserted into radial or femoral artery and threaded to aorta, a dye indicates the location of the blockage

Question 15

Name 2 tests that can be performed on a patient with a stable MI involving the effects of exercise

Answer 15

Exercise ECG stress test: patient exercises until target HR/symptoms start

Stress echocardiography; give dobutamine (b1 agonist) to mimic exercise, see where damaged tissue is

Question 16

What drugs can you give for the following

a) Venodilation
b) decrease HR and contractility
c) Decrease afterload
d) Decrease platelet aggregation
e) decrease LDLs and cholesterol

Answer 16

a) nitrates
b) B-blockers, Ca2+ channel inhibitors
c) ACE inhibitors
d) aspirin
e) statins

Question 17

Name 3 arteries and 1 vein that can be used for performing a coronary artery bypass

Answer 17

Left and R internal mammary artery, radial artery

Saphenous vein

Question 18

What does a PCI stand for, what is it used for?

Answer 18

Percutaneous Coronary Intervention: angioplasty and stents, inflate ‘balloon-like’ device to open artery, put in stent

Question 19

Describe the presentation of acute coronary syndromes

Answer 19

RFs, pain is frequent/severe/longer and brought on with little-no exertion, lasts >15 min

Question 20

Name as many signs/symptoms as you can that might be experienced by a patient close to having an MI

Answer 20

Patient distress: anxious, “impending doom”

Increased sympathetic activity and hypotensive: clammy, tachycardia, sweaty, pale, nausea, vomiting, pre/syncope

Signs of HF: S3, S4
LVF: Crackles in lung bases

Question 21

What differentiates a STEMI from an Unstable Angina or NSTEMI on an ECG?

Answer 21

STEMI: ST elevation (transmural infarction)

NSTEMI or Unstable Angina: ST depression

Question 22

What can be found in the plasma during cardiac pathologies and what are they indicative of?

Answer 22

Creatine kinase - muscle damage

Troponin - myocyte death
+ in (N)STEMI but NOT unstable angina (no myocyte death)

Question 23

How would you manage a patient presenting with chest pain or symptoms suggestive of an MI?

Answer 23

Quick ECG

• ST elevation -> PPCI pathway, if can’t get them there by 2 hours give thrombolytic drugs
• No persistent ST elevation: repeat ECG (make sure)

Question 24

What immediate treatment would you provide for an NSTEMI? (4)

Answer 24

Anti-thrombotic therapy: anticoagulants; heparin

Anti-platelet agents: aspirin and clopidogrel

Anti-ischemic therapy: B-blockers, IV nitrates

General measures: pain control, oxygen if needed

Question 25

What are pathological reasons someone might have a sinus tachycardia or sinus bradycardia?

Answer 25

Tachycardia: HF (pain, anxiety)
Bradycardia: SA node ischemia

Question 26

Name 5 complications of an MI

Answer 26

AF, Arrhythmias, heart block, HF, cardiogenic shock, death

Question 27

Why does ST-depression/ST elevation occur?

Answer 27

Ischemia triggers K+ to leak out from injured sub-endocardium -> causes depolarisation -> ST depression

Question 28

What surgical treatment could you provide for a pericardial effusion?

Answer 28

Pericardiocentesis: aspirate fluid from pericardial sac

Question 29

Name 3 clinical features you could use to diagnose an aortic dissection?

Answer 29

1. Pain: immediate onset, tearing character, radiates to btwn shoulder blades
2. Variation in pulse and/or BP between R and L arm
3. Mediastinal and/or aortic widening on chest radiograph

Question 30

When should creatine kinase be detectable in the blood?

Answer 30

3-5 hours after an MI

Question 31

What ECG signs indicate an MI?

Answer 31

NSTEMI, STEMI, T wave inversion and/or peaked, pathological Q waves