IHD 4

Question 1

What are cardiac causes of chest pain?

Answer 1

Stable, chronic IHD
Acute Coronary syndrome (ACS)
-Unstable angina
-STEMI
-NSTEMI

Question 2

What are some common non-cardiac causes of chest pain

Answer 2

-Pneumonia
-Viral pleuritis
-GORD (Gastro Oesophageal Reflux Disease)
-Costochondritis
-Anxiety/panic disorder

Question 3

What are some uncommon cardiac causes of chest pain

Answer 3

-Pericarditis
-Cardiac tamponade
-Aortic dissection
-Pneumothorax/pulmonary embolism (more resp)

Question 4

What is the diagnosis of chronic, stable IHD?

Answer 4

Stress testing:
>1mm of ST segment depression/ST elevation during or after exercise

Coronary angiography:
-Evidence of coronary artery narrowing

CT coronary angiography:
-Identification of stenosis

Hx and symptoms:
-Known history of coronary artery disease
-Chest discomfort on exertion, relieved by GTN or rest
-No diaphoresis, nausea, dyspnoea

ECG:
-No acute changes
-May have evidence of previous infarction (Q waves)

Cardiac biomarkers:
-Not elevated

Question 5

What is the diagnosis of ACS?

Answer 5

Hx and symptoms:
-Central chest pressure (radiation to jaw/upper extremities)
-Diaphoresis, nausea, dyspnoea

Coronary angiography:
STEMI: Critical occlusion of a coronary artery
NSTEMI and unstable angina: Evidence of coronary artery narrowing

ECG:
-STEMI - ST segment elevation >1mm in 2 or more anatomically contiguous leads
-NSTEMI/unstable angina - Non-specific ST segment depression or T wave inversion

Cardiac biomarkers:
-Elevated in STEMI and NSTEMI
-Not elevated in unstable angina

Question 6

Features of unstable angina

Answer 6

-Ischaemia but no injury. Angina may progress to infarction.
-Acute chest pain
-With activity and rest
-Biomarkers not raised
-ST depression on ECG

Question 7

Features of NSTEMI

Answer 7

-Subendocardial infarction
-ECG changes of ischaemia: ‘ST depression and T wave changes’
-Raised biomarkers
-Symptoms lasting despite rest
-Diaphoresis

Question 8

Features of STEMI

Answer 8

-ST elevation of more than 1mm in at least 1 limb lead and more than 2mm in at least 2 chest leads
-New LBBB
-Raised biomarkers
-Positive troponin
-Symptoms lasting despite rest
-Diaphoresis

Question 9

Describe progression of cell death in STEMI

Answer 9

Cell death does not occur immediately
It depends on:
-Collateral circulation
-Extent of occlusion

At 30-40 mins:
-Irreversible cell death of the myocardium begins and function is impaired

At 6-8 hours:
-Necrosis of the ischaemic myocardium is established

Question 10

Extent of occlusion in stable angina, unstable angina, NSTEMI and STEMI

Answer 10

Stable angina
-Restriction of blood flow due to atherosclerotic plaque
-Vessel can’t dilate enough to meet myocardial demand

Unstable angina
-Plaque ruptures and thrombus forms
-Partial occlusion of the vessel

NSTEMI
-Partial occlusion results in infarct to the subendocardial myocardium

STEMI
-Complete occlusion results in transmural infarct to the myocardium