High-Yield Cardiology for Medical Exams: Revision Guide

Cardiology is one of the most heavily tested systems in every licensing exam, from USMLE and PLAB to the AMC and the Gulf licensing exams. The good news: a small set of conditions and decision points produces most of the questions. This guide is written as exam revision. It summarises how major guidelines frame first-line management so you can pick the best answer; it is not a substitute for local protocols or clinical judgement.

How cardiology questions are built

Most stems give you one of four tasks:

1. Name the diagnosis from symptoms, signs and an ECG or echo finding.
2. Choose the next step (investigation or immediate treatment).
3. Choose long-term therapy, often "which drug reduces mortality".
4. Spot the adverse effect or contraindication of a cardiac drug.

Before you look at the options, decide which task the question is asking. "Most appropriate next step" in a haemodynamically unstable patient almost always means immediate stabilisation, not another test.

Acute coronary syndromes

ACS covers unstable angina, NSTEMI and STEMI. The split is made on the ECG and troponin.

Immediate management themes

• Aspirin loading dose for all unless truly contraindicated, plus a second antiplatelet (P2Y12 inhibitor) per guideline.
• Oxygen only if saturations are low; routine oxygen in normoxic patients is no longer recommended.
• Nitrates for pain unless hypotensive, right ventricular infarction is suspected, or a phosphodiesterase-5 inhibitor was taken recently.
• Opioid analgesia for ongoing pain.

Secondary prevention ("the post-MI bundle")

• Dual antiplatelet therapy, usually for 12 months, then single antiplatelet.
• High-intensity statin.
• Beta blocker, particularly if left ventricular function is reduced.
• ACE inhibitor (or ARB if intolerant).
• Cardiac rehabilitation, smoking cessation, risk factor control.

ECG territories

Exam trap: inferior STEMI with hypotension and clear lungs suggests right ventricular involvement. Nitrates can cause profound hypotension; fluids are the classic answer.

Complications by timing

• First hours to days: arrhythmias (VF is the main cause of early death), cardiogenic shock, heart block (especially inferior MI).
• Around days 3–7: papillary muscle rupture (acute mitral regurgitation, pulmonary oedema), ventricular septal rupture (new pansystolic murmur, step-up in oxygen saturation), free wall rupture with tamponade.
• Weeks: Dressler syndrome (pericarditis with fever), left ventricular aneurysm (persistent ST elevation).

Heart failure

Heart failure is classified by ejection fraction: reduced (HFrEF, usually 40% or below), mildly reduced, and preserved (HFpEF). The most testable content is drug therapy for HFrEF.

Recent European guidance frames four "pillars" for HFrEF: an ACE inhibitor/ARNI, a beta blocker, an MRA and an SGLT2 inhibitor. UK guidance describes a stepwise approach. Exams usually reward knowing which drugs reduce mortality and which only improve symptoms.

Acute heart failure

Sit the patient up, give oxygen if hypoxic, intravenous loop diuretic, and consider nitrates if blood pressure allows. Non-invasive ventilation for respiratory distress. Look for the trigger: ischaemia, arrhythmia, infection, non-adherence, or new valve disease.

Atrial fibrillation

AF questions follow a reliable sequence.

1. Unstable? Shock, syncope, myocardial ischaemia or heart failure from the arrhythmia means synchronised DC cardioversion.
2. Rate or rhythm? Most stable patients get rate control first (beta blocker or rate-limiting calcium channel blocker; digoxin in sedentary patients or as an add-on). Rhythm control is considered for new-onset AF, reversible cause, heart failure driven by AF, or symptoms despite rate control.
3. Duration and cardioversion: if onset is under 48 hours, cardioversion can be considered with anticoagulation cover; if longer or unknown, anticoagulate for at least three weeks first or exclude left atrial thrombus with transoesophageal echo.
4. Stroke prevention: calculate CHA2DS2-VASc and assess bleeding risk. Direct oral anticoagulants are first line for non-valvular AF in current guidelines. Warfarin remains the choice with mechanical valves and moderate to severe mitral stenosis.

Exam trap: aspirin alone is not an acceptable stroke-prevention strategy in AF.

Hypertension

Diagnosis in UK practice relies on ambulatory or home blood pressure monitoring to confirm clinic readings. First-line drug choice depends on age, ethnicity and comorbidity in UK guidance; US guidance focuses on thiazide-type diuretics, ACE inhibitors/ARBs and calcium channel blockers as first-line classes.

Exam traps: ACE inhibitors and ARBs are contraindicated in pregnancy; ACE inhibitor plus ARB together is not recommended; a young patient with resistant hypertension and low potassium suggests primary hyperaldosteronism.

Hypertensive emergency

Severely raised pressure with acute organ damage (encephalopathy, aortic dissection, pulmonary oedema, acute kidney injury, eclampsia). Treat with intravenous agents and controlled reduction; dropping pressure too fast risks ischaemia. Aortic dissection is the exception where rapid reduction is the target.

Valve disease

Exam trap: manoeuvres. Almost all murmurs get quieter with Valsalva; hypertrophic cardiomyopathy and mitral valve prolapse get louder or earlier.

Infective endocarditis

Suspect in fever plus new murmur, especially with intravenous drug use (tricuspid valve, Staphylococcus aureus), prosthetic valves or recent dental work. Diagnosis uses the modified Duke criteria: major criteria are positive blood cultures with typical organisms and evidence of endocardial involvement on echo. Take at least three sets of blood cultures before antibiotics in a stable patient.

Pericardial disease

• Acute pericarditis: pleuritic chest pain relieved by sitting forward, friction rub, widespread saddle-shaped ST elevation with PR depression. NSAIDs plus colchicine are first line in most guidelines.
• Tamponade: Beck's triad (hypotension, raised JVP, muffled heart sounds), pulsus paradoxus, electrical alternans. Treatment is urgent pericardiocentesis.

ECG patterns worth instant recognition

• Hyperkalaemia: tall tented T waves, flattened P waves, broad QRS, sine wave.
• Hypokalaemia: U waves, flat T waves, prolonged QT appearance.
• Wolff-Parkinson-White: short PR, delta wave; avoid AV-node blockers in pre-excited AF.
• Brugada pattern: coved ST elevation in V1–V2.
• Long QT: risk of torsades de pointes; treat torsades with intravenous magnesium.
• Complete heart block: P waves and QRS complexes unrelated; consider atropine then pacing if compromised.

Common exam traps in cardiology

• Giving a beta blocker or rate-limiting calcium channel blocker to a patient in cardiogenic shock.
• Combining verapamil with a beta blocker (risk of profound bradycardia and heart block).
• Forgetting that loop diuretics improve symptoms but not survival.
• Choosing a stress test in a patient with ongoing ischaemic chest pain and ST elevation; reperfusion comes first.
• Missing aortic dissection in "MI" with tearing back pain and unequal arm pressures; antiplatelets and anticoagulation are dangerous here.
• Overlooking digoxin toxicity in a patient on diuretics with new hypokalaemia.

How to revise cardiology efficiently

Use active recall: draw the ACS pathway, the HFrEF drug ladder and the AF decision tree on a blank page, then check them. Do mixed question blocks so ECG recognition stays fresh. The MediFlow Exam Prep app includes exam-style cardiology questions with explanations and re-tests the ones you miss. For a method, see active recall and practice questions, and pair this guide with high-yield pharmacology and emergency medicine and ACLS.

Summary

• ACS: classify by ECG and troponin; STEMI needs immediate reperfusion.
• HFrEF: know the four mortality-reducing classes; diuretics are symptomatic.
• AF: stability first, then rate versus rhythm, then anticoagulation by risk score.
• Hypertension: confirm the diagnosis; choose drugs by age, ethnicity, pregnancy and comorbidity.
• Murmurs and ECG patterns are pattern recognition: drill them until they are instant.