Essential Cardiology Clinical Reference and Management

Posted on Jun 12, 2026 in Medicine

1. Acute Coronary Syndrome (ACS)

Diagnosis Patterns

  • STEMI: ST elevation in contiguous leads OR new LBBB.
  • Posterior MI: ST depression V1–V3 + tall R waves.
  • Inferior MI: II, III, aVF (RCA → AV node → AV block risk).
  • Lateral MI: I, aVL, V5–V6 (LCx).
  • Wellens: Deep/biphasic T waves V2–V3 → critical LAD stenosis.
  • Troponin rise: Not always plaque rupture (can be sepsis, demand ischaemia).

STEMI Management

  • PCI if within 12h + within 120 min pathway.
  • Otherwise fibrinolysis (within 12h).
  • Repeat ECG 60–90 min post-fibrinolysis.
  • If failed thrombolysis → rescue PCI.
  • PCI: Aspirin + P2Y12 + heparin (± GPI).

NSTEMI / UA

  • NSTEMI: Troponin ↑.
  • UA: Troponin normal.
  • GRACE >3% → angiography within 72h.
  • Unstable → immediate angiography.
  • All ACS → aspirin 300 mg.

Antiplatelets:

  • Conservative NSTEMI: Aspirin + ticagrelor OR clopidogrel (high bleed risk).
  • PCI: Prasugrel/ticagrelor (clopidogrel if anticoagulated).

ACS Complications

  • Papillary muscle rupture: Acute MR → flash pulmonary oedema.
  • VSD: 3–5 days post MI → pansystolic murmur.
  • Free wall rupture: 5–10 days → tamponade (JVP ↑, hypotension, muffled sounds).
  • LV aneurysm: Persistent ST elevation weeks later.
  • Dressler syndrome: Fever + pleuritic pain weeks later.
  • Cardiogenic shock: Poor prognosis.

Key Contraindications

  • Nitrates contraindicated if SBP < 90 or severe AS.
  • ACE-i contraindicated in pregnancy.

2. Arrhythmias

Atrial Fibrillation

  • CHA2DS2-VASc → decide anticoagulation.
  • DOAC first-line.
  • ORBIT score = bleeding risk.
  • Falls ≠ contraindication to anticoagulation.
  • Post-stroke: Anticoagulate after 2 weeks (if haemorrhage excluded).
  • TIA: Start immediately if imaging clear.

Cardioversion:

  • <48h → can cardiovert.
  • >48h → anticoagulate 3 weeks OR TOE.

Rate Control:

  • Beta blocker first-line.
  • Add digoxin second-line.

SVT

  • First-line: Vagal manoeuvres.
  • Then adenosine (6 → 12 → 18 mg).
  • Asthma → verapamil alternative.

VT

  • Unstable → DC cardioversion.
  • Stable broad complex → IV amiodarone.
  • Verapamil contraindicated in VT.

Bradycardia

  • Atropine 500 mcg (max 3 mg).
  • If fails → transcutaneous → transvenous pacing.
  • Isoprenaline/adrenaline infusion alternative.
  • Atropine NOT used in asystole/PEA (ALS update).

WPW / Long QT / Special ECG

  • WPW: Delta wave + slurred upstroke.
  • Long QT: Torsades risk (macrolides, citalopram, hypokalaemia, hypothermia).
  • Torsades: IV magnesium sulfate.

3. Heart Failure

HFrEF (4 Pillars)

  • ACE-i / ARB (or ARNI).
  • Beta blocker.
  • MRA (spironolactone/eplerenone).
  • SGLT2 inhibitor.

Add:

  • IV iron if deficient.
  • Flu vaccine yearly.
  • CRT if wide QRS.

Acute HF

  • IV loop diuretics.
  • Nitrates if SBP >100.
  • CPAP if refractory.
  • Inotropes (dobutamine) if shock.

Key Signs

  • S3 = LV failure.
  • Raised JVP + oedema + hepatomegaly = right HF.
  • Gallop rhythm = LV failure.

Important Associations

  • Alcohol → dilated cardiomyopathy.
  • Severe anaemia → high output HF.

4. Valves & Murmurs

Aortic Stenosis

  • Ejection systolic murmur → radiates to carotids.
  • Syncope + angina + dyspnoea.
  • Treat: AVR if symptomatic.
  • Contraindication: Nitrates.

Aortic Regurgitation

  • Early diastolic murmur.
  • Collapsing pulse, Quincke, De Musset.
  • Causes: Marfan, endocarditis.

Mitral Stenosis

  • Rheumatic fever most common.
  • Opening snap.
  • Mid-diastolic rumble.
  • AF common.

Mitral Regurgitation

  • Holosystolic blowing murmur.
  • Papillary rupture → acute MR → flash pulmonary oedema.

Right-Sided Murmurs

  • TR louder on inspiration.
  • TR → raised JVP, pulsatile liver.

5. Endocarditis

  • Most common overall: Staph aureus.
  • IVDU: Tricuspid valve.
  • Post valve surgery (<2 months): S. epidermidis.
  • Poor dental hygiene: Viridans strep.
  • Duke criteria used for diagnosis.
  • 3 blood cultures needed.
  • Surgery if: heart failure, uncontrolled infection, abscess, or emboli despite antibiotics.

6. Pulmonary Embolism

Diagnosis

  • CTPA first-line.
  • V/Q scan if renal impairment.
  • Wells score: ≤4 + D-dimer → exclude; >4 → CTPA.
  • PERC only if very low risk.

Management

  • DOAC first-line.
  • Massive PE + hypotension → thrombolysis.
  • Unprovoked → 6 months.
  • Provoked → 3 months.

Clues

  • Sinus tachycardia most common ECG finding.
  • S1Q3T3 = rare but classic.
  • Normal CXR.

7. Aortic Dissection

  • Type A → surgery + IV labetalol.
  • Type B → medical (BP control).
  • CT angiography = gold standard.
  • TOE if unstable.
  • Pulse deficit, tearing chest pain, neuro symptoms.

8. Hypertension (NICE Framework)

Diagnosis

  • ABPM preferred.
  • Stage 1 = 140/90.
  • Stage 2 = 160/100.
  • Severe = ≥180/120 (emergency if end-organ damage).

Treatment Ladder

  • ACE-i → + CCB → + thiazide → add spironolactone.
  • >55 or Black African: CCB first → add ACE-i/ARB → then thiazide.
  • Diabetes: ACE-i/ARB first-line regardless of age.

Key Drug Effects

  • ACE-i → hyperkalaemia, renal artery stenosis issue.
  • Thiazides → hypokalaemia, gout, hypercalcaemia.
  • CCB → ankle swelling, flushing.
  • Beta blockers → erectile dysfunction, cold peripheries.

9. ECG High-Yield

  • Hyperkalaemia → peaked T waves.
  • Hypokalaemia → U waves, long QT.
  • Hypercalcaemia → short QT.
  • Hypothermia → J waves.
  • Pericarditis → PR depression + saddle ST elevation.
  • Tamponade → electrical alternans.
  • PE → sinus tachycardia.

10. ALS / Emergencies

  • VF/VT: Shock → amiodarone after 3 shocks.
  • Adrenaline: 1 mg every 3–5 min.
  • Asystole/PEA: CPR + adrenaline (no atropine).
  • IO route if no IV access.
  • Left lateral tilt in pregnancy >20 weeks.
  • CPR ratio 30:2.
  • Thrombolysis in arrest if PE suspected → prolonged CPR.

11. Toxicology & Interactions

  • Digoxin toxicity ↑ with hypokalaemia, amiodarone, thiazides.
  • Digibind = antidote.
  • Warfarin reversed by vitamin K + PCC.
  • Macrolides + statins → rhabdomyolysis risk.
  • Macrolides → QT prolongation.
  • Flecainide only if no structural heart disease.