NAC OSCE Diagnostic Investigations & Data Interpretation 2

Question 1

A 62-year-old man with acute chest pain has an ECG showing ST elevation in leads II, III, and aVF with reciprocal ST depression in leads I and aVL. Which coronary artery is most likely occluded?

Accepted Answer

Right coronary artery

Answer

ST elevation in the inferior leads (II, III, aVF) with reciprocal changes in the lateral leads (I, aVL) indicates an inferior STEMI, most commonly due to right coronary artery occlusion.

Question 2

A 70-year-old woman presents with palpitations. ECG shows an irregularly irregular rhythm, no identifiable discrete P waves, and a ventricular rate of 118 bpm. What is the diagnosis?

Accepted Answer

Atrial fibrillation

Answer

Atrial fibrillation is characterized by an irregularly irregular ventricular rhythm with absent distinct P waves, reflecting chaotic atrial electrical activity.

Question 3

A 55-year-old man's ECG shows a PR interval of 240 ms with every P wave followed by a QRS complex and no dropped beats. What is the correct interpretation?

Accepted Answer

First-degree AV block

Answer

First-degree AV block is defined by a PR interval >200 ms (0.20 s) with 1:1 conduction of all P waves — prolonged conduction but no dropped beats.

Question 4

A 30-year-old man presents with sudden onset dyspnea and right-sided pleuritic chest pain. CXR shows a hyperlucent right hemithorax with absent lung markings and tracheal deviation to the left. What is the most appropriate immediate intervention?

Accepted Answer

Needle decompression at the right 2nd intercostal space, midclavicular line

Answer

The CXR and clinical features indicate tension pneumothorax, a life-threatening emergency requiring immediate needle decompression without delay for imaging confirmation.

Question 5

A 65-year-old woman with dyspnea has a CXR showing bilateral perihilar infiltrates in a 'bat-wing' pattern, Kerley B lines, and cardiomegaly. What is the most likely diagnosis?

Accepted Answer

Cardiogenic pulmonary edema

Answer

Bilateral perihilar ('bat-wing') infiltrates, Kerley B lines (interstitial edema), and cardiomegaly on CXR are classic radiographic signs of cardiogenic pulmonary edema.

NAC OSCE Practice Test

NAC OSCE Practice Test

NAC OSCE Diagnostic Investigations & Data Interpretation 2