Q1. Which leads correspond to an INFERIOR myocardial infarction? A. V1–V4 B. II, III and aVF C. I, aVL, V5–V6 D. V1–V2 only ANSWER: B — II, III and aVF. Why: these leads face the inferior surface, usually supplied by the right coronary artery. A: anterior/septal (LAD). C: lateral (circumflex). D: septal leads; tall R waves here suggest posterior MI. LEARNING POINT: lead group → territory → artery is a three-step chain worth knowing cold.

Q2. What distinguishes unstable angina from NSTEMI? A. The presence of ST elevation B. A raised troponin C. The duration of pain D. Response to nitrates ANSWER: B — a raised troponin. Why: both show ST depression or T inversion, or a normal ECG. Troponin indicates that myocardial cells have died, which makes it an NSTEMI. A: ST elevation would make it a STEMI. LEARNING POINT: the distinction is made retrospectively and does not change initial management.

Q3. A 60-year-old has 3 mm ST elevation in II, III and aVF. BP is 92/56 and V4R shows ST elevation. He has ongoing pain. Which drug should be AVOIDED? A. Aspirin B. Glyceryl trinitrate C. Morphine D. Clopidogrel ANSWER: B — glyceryl trinitrate. Why: V4R elevation confirms right ventricular infarction. The RV depends on preload; nitrates reduce preload and can cause profound hypotension. A, D: antiplatelets are indicated. C: analgesia is appropriate, with care given the BP. LEARNING POINT: inferior STEMI → right-sided leads → if RV involved, no nitrates and cautious fluid instead.

Q4. A patient arrives 90 minutes after chest pain onset. ECG is normal and the initial troponin is normal. The correct action is: A. Discharge — ACS is excluded B. Repeat troponin after the appropriate interval and repeat the ECG C. Immediate thrombolysis D. Discharge with outpatient follow-up only ANSWER: B — repeat both. Why: troponin does not rise measurably until roughly 3–6 hours after injury, so a sample at 90 minutes cannot exclude infarction. The change between samples is what matters. C: no ST elevation, so thrombolysis is not indicated. LEARNING POINT: one early negative troponin proves nothing.

Q5. A 76-year-old diabetic woman presents with sudden breathlessness, sweating and nausea. No chest pain. The most appropriate immediate investigation is: A. Chest X-ray only B. 12-lead ECG C. Spirometry D. Reassure and discharge ANSWER: B — 12-lead ECG. Why: diabetic, elderly and female patients frequently have silent or atypical infarction because autonomic neuropathy blunts cardiac pain. The absence of chest pain does not exclude ACS in this group. LEARNING POINT: these are the infarcts that get sent home. Keep the threshold for an ECG low.

Q6. An ECG shows ST DEPRESSION with tall R waves in V1–V2, and the patient has ongoing severe chest pain. The most likely diagnosis is: A. Anterior NSTEMI B. Posterior STEMI C. Pericarditis D. Normal variant ANSWER: B — posterior STEMI. Why: the posterior wall is not directly viewed by standard leads, so a posterior infarct appears as the MIRROR image in V1–V2: ST depression with tall R waves. Confirm with posterior leads. It is treated as a STEMI equivalent. A: would give ST changes in the anterior leads themselves. C: pericarditis gives widespread saddle-shaped elevation. LEARNING POINT: the most missed STEMI, because it looks like the opposite of what you are searching for.

Q7. Three days after an inferior MI, a patient becomes acutely breathless with a new loud pansystolic murmur and hypotension. The most likely cause is: A. Dressler syndrome B. A mechanical complication such as papillary muscle or septal rupture C. Stable angina D. Anxiety ANSWER: B — a mechanical complication. Why: rupture of the papillary muscle (acute mitral regurgitation) or the interventricular septum typically occurs some days after infarction and presents with a NEW murmur, sudden deterioration and shock. A: Dressler syndrome occurs weeks later and causes pericarditic pain, not a new murmur with shock. LEARNING POINT: a new murmur with sudden deterioration after an MI is a mechanical complication until proven otherwise.