MRCP Part 1 Cardiology 1

Question 1

A 60-year-old man presents with central chest pain radiating to the jaw, diaphoresis, and an ECG showing ST elevation in leads II, III, and aVF. Which coronary artery is most likely occluded?

Accepted Answer

Right coronary artery

Answer

Inferior STEMI (ST elevation in II, III, aVF) is most commonly caused by occlusion of the right coronary artery (RCA), which supplies the inferior wall of the left ventricle in the majority of patients (right-dominant circulation).

Question 2

Which drug class is absolutely contraindicated in acute decompensated heart failure with cardiogenic shock?

Accepted Answer

Beta-blockers

Answer

Beta-blockers are absolutely contraindicated in acute decompensated heart failure with cardiogenic shock because their negative inotropic and chronotropic effects further reduce cardiac output in an already compromised heart. They may be initiated after stabilisation.

Question 3

A 45-year-old woman has recurrent palpitations. A 24-hour Holter shows intermittent delta waves and short PR interval. What is the diagnosis?

Accepted Answer

Wolff-Parkinson-White syndrome

Answer

Wolff-Parkinson-White syndrome is characterised by a delta wave (slurred upstroke of QRS), short PR interval (<120ms), and wide QRS. It results from an accessory conduction pathway (Bundle of Kent) bypassing the AV node.

Question 4

What is the mechanism of action of digoxin in atrial fibrillation?

Accepted Answer

Blocks sodium-potassium ATPase, increasing vagal tone and slowing AV node conduction

Answer

Digoxin inhibits the Na+/K+ ATPase pump, leading to increased intracellular sodium, reduced calcium efflux, and enhanced cardiac contractility. In AF, it slows ventricular response by increasing vagal tone and reducing AV node conduction velocity.

Question 5

In a patient with HOCM, which intervention is most likely to worsen outflow tract obstruction?

Accepted Answer

Valsalva manoeuvre

Answer

Valsalva manoeuvre reduces venous return, decreasing LV preload. In HOCM, reduced LV cavity size worsens the dynamic outflow tract obstruction. Squatting increases preload and reduces obstruction. Beta-blockers reduce the obstruction by slowing heart rate and reducing contractility.

MRCP Part 1 Practice Test

MRCP Part 1 Practice Test

MRCP Part 1 Cardiology 1