CVS 17 - Chest Pain + Acute Coronary Syndrome

Question 1

When chest pain is the presenting complaint, how do we reach a diagnosis?

Answer 1

• History, clinical examination then further investigations.
• Take a history to build an illness script (using SQITARS) to help narrow down causes.
• There are multiple categories of potential causes of chest pain - e.g.: MSK such as rib fractures, GI such as GORD or respiratory such as pneumonia or pulmonary embolism.

Question 2

What are the 3 potentially life threatening heart conditions in which chest pain might be the presenting complaint?

Answer 2

1) Unstable Angina
2) ST-elevation myocardial infarction (STEMI)
3) Non-ST-elevation myocardial infarction (NSTEMI)

Question 3

What is the difference between “visceral/cardiac” and “somatic/pleural” chest pain?

Answer 3

Visceral/Cardiac = Pain originated from deeper structure (e.g.: heart + lungs), via visceral afferent nerves. Less able to localise, dull pain felt centrally Pain may be referred (arising from another location) (Worsened by exertion).

Somatic/Pleuritic = Originates from more superficial structures, e.g.: chest wall, pericardium + parietal pleura, via somatic afferent nerves. Brain able to accurately locate site of pain - sharp pain. (Worsened by chest movement - breathing in/coughing).

Question 4

What are the potential cardiac causes of chest pain?

Answer 4

1) Acute coronary syndromes (unstable angina, STEMI, NSTEMI)
2) Pericarditis (inflammation of the pericardium)

Question 5

What features of a patient history, clinical examination + further investigations (ECG) indicate pericarditis?

Answer 5

History = Males>Females, retrosternal sharp pain aggravated by breathing in/coughing/lying flat.

Clinical examination = Pericardial rub on auscultation of heart

Further = Saddle-shaped ST elevation on ECG

Question 6

Describe the pathophysiology of the 3 main acute coronary syndromes

Answer 6

• Atherosclerotic plaque occludes coronary artery. Occlusion reaches 70-80% to cause symptoms.
• Plaque not large enough to cause symptoms at rest in stable angina, only occur upon exertion.
• Plaque ruptures causing thrombus formation, increasing severity of occlusion
• Entirely occlusive = STEMI, partially occlusive = NSTEMI, Unstable plaque = Unstable Angina.

Question 7

How do you differentiate between a patient with stable + unstable angina?

Answer 7

Stable = Chest pain upon exertion, not at rest. No troponins as no tissue death. ECG normal, slightly changed during episode.

Unstable = Chest pain at rest, longer lasting episodes of pain. No troponins as no tissue death. ST-depression consistent w/ischaemia

Question 8

How do you differentiate between a patient with angina and myocardial infarction?
How do you differentiate between a patient with STEMI + NSTEMI?

Answer 8

• An obvious rise in troponins in blood test, as they are released upon cardiac myocyte death.
• ST-elevation present on ECG in STEMI