NEET-PG Cardiology: The 10 ECG Patterns You Cannot Afford to Miss

ECG interpretation is one of the most heavily-tested areas of NEET-PG. Yet many candidates lose marks not because they can't read ECGs, but because they haven't practised systematically.

The 10 Patterns

1. STEMI — Recognising the Territory

Anterior STEMI: ST elevation in V1–V4. LAD territory. Look for reciprocal changes in II, III, aVF.

Inferior STEMI: ST elevation in II, III, aVF. RCA or LCx. Always check V3R/V4R for right ventricular involvement.

2. LBBB — The Masquerader

Left Bundle Branch Block (QRS >120ms, broad monophasic R in V5–V6, QS in V1) can mask an acute MI. In the context of chest pain, treat new LBBB as STEMI equivalent.

3. Hyperkalaemia — A Silent Killer

Peaked T waves are the earliest sign. As K⁺ rises: widening QRS → sine wave pattern → VF. In a renal patient with a broad QRS, always check K⁺.

4. Atrial Fibrillation — Irregularly Irregular

No P waves. Irregularly irregular rhythm. Rate can be fast (>100 bpm) or controlled. The NEET-PG question usually asks about rate control vs rhythm control, or when to anticoagulate (CHA₂DS₂-VASc).

5. Complete Heart Block — Third Degree AV Block

P waves and QRS complexes bear no relationship to each other. Atrial rate > ventricular rate. The escape rhythm is wide (idioventricular) or narrow (junctional). Clinical: hypotension, syncope, Stokes-Adams attacks.

6. WPW — Pre-Excitation

Short PR interval (<0.12s), delta wave (slurred upstroke of QRS), broad QRS. The danger: AF in WPW can conduct rapidly via the accessory pathway → VF. Do NOT give AV nodal blockers (digoxin, verapamil, adenosine).

7. Long QT

QTc >440ms (males), >460ms (females). Causes: drugs (amiodarone, haloperidol, erythromycin), hypokalaemia, hypomagnesaemia, hypothyroidism, congenital. Risk: Torsades de Pointes.

8. Pulmonary Embolism

Classic (but rare): S1Q3T3 — S wave in lead I, Q wave and T-wave inversion in lead III. More common: sinus tachycardia ± right heart strain (T-wave inversion V1–V4, RBBB).

9. Ventricular Tachycardia

Regular, broad QRS tachycardia (QRS >120ms). Rate 140–220 bpm. If in doubt: assume VT over SVT with aberrancy. Capture beats and fusion beats confirm VT.

10. Pericarditis

Saddle-shaped ST elevation in multiple leads (not territory-specific). PR depression is the most specific sign. No reciprocal changes (unlike STEMI).

The 60-Second Approach

Rate → Rhythm → Axis → P wave → PR interval → QRS width → ST segment → T waves → QT interval. Every time. Without fail.

Dr. Ahmed runs NEET-PG Cardiology Masterclasses every month on MedNext Live. Join free with your MedNext account.