Explain me 10 common heart diseases with ECG changes and ECG images of those diseases

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ECG electrocardiogram myocardial infarction ST elevation

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atrial fibrillation ECG irregularly irregular rhythm

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heart block complete AV block ECG third degree

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ventricular tachycardia ECG wide complex tachycardia

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left ventricular hypertrophy ECG high voltage

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Wolff-Parkinson-White syndrome ECG delta wave short PR

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pericarditis ECG saddle-shaped ST elevation diffuse

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pulmonary embolism ECG S1Q3T3 right heart strain

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long QT syndrome ECG prolonged QT interval Torsades de Pointes

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hypertrophic cardiomyopathy ECG deep Q waves ST changes

Here is a comprehensive guide to 10 common heart diseases with their characteristic ECG changes and illustrative ECG images.

10 Common Heart Diseases with ECG Changes

1. 🫀 ST-Elevation Myocardial Infarction (STEMI)

Pathophysiology

Complete occlusion of a coronary artery (most commonly the LAD) leads to transmural ischemia and myocyte death. The injury current creates measurable ST changes on ECG.

ECG Changes

Hyperacute T-waves (earliest sign — tall, peaked, symmetric)
ST elevation ≥1 mm in ≥2 contiguous leads (convex/tombstone morphology)
Reciprocal ST depression in anatomically opposite leads
Pathological Q waves (>40 ms wide, >25% R wave height) — sign of completed infarction
T-wave inversions in the evolutionary phase

Territory	Culprit Vessel	Leads with ST Elevation
Anterior	LAD	V1–V4
Inferior	RCA	II, III, aVF
Lateral	LCx	I, aVL, V5–V6
Posterior	RCA/LCx	ST depression V1–V3 (mirror image)

ECG Image — Anterior STEMI (LAD Occlusion)

Anterior STEMI — ST elevation V2–V5 with reciprocal changes in inferior leads

Classic anterolateral STEMI: prominent convex ST elevation in V1–V6, hyperacute T-waves in V2–V4, reciprocal depression in II, III, aVF — indicates proximal LAD occlusion.

2. ❤️ Inferior STEMI

ECG Changes

ST elevation in II, III, aVF (inferior leads)
ST depression in I, aVL (reciprocal high lateral changes)
ST elevation III > II suggests RCA occlusion
ST elevation II > III with lateral involvement suggests LCx

ECG Image — Inferolateral STEMI

Inferolateral STEMI — ST elevation II, III, aVF, V4–V6 with reciprocal changes in I, aVL

Green circles mark ST elevation in inferior and lateral leads; yellow arrows indicate reciprocal depression in high lateral leads (I, aVL) and anterior precordials.

3. 🔥 Acute Pericarditis

Pathophysiology

Inflammation of the pericardium causes diffuse epicardial irritation. The inflamed myocardium generates a broad "injury current" not confined to one vascular territory.

ECG Changes (4 Stages)

Stage 1: Diffuse concave ("saddle-shaped") ST elevation in almost all leads (except aVR and V1); PR depression (pathognomonic); PR elevation in aVR
Stage 2: ST returns to baseline; T-waves flatten
Stage 3: Diffuse T-wave inversions
Stage 4: ECG normalizes

Key differentiator from STEMI: Pericarditis ST elevation is diffuse, concave, and accompanied by PR depression. STEMI ST elevation is regional, convex, with reciprocal changes.

Spodick's sign: Downsloping TP segment (present in ~80%)

ECG Image — Acute Pericarditis

Acute Pericarditis — diffuse saddle-shaped ST elevation, PR depression in II, PR elevation in aVR

Diffuse concave ST elevation across I, II, III, aVF, V2–V6 with PR depression in II and reciprocal PR elevation in aVR — classic acute pericarditis pattern.

4. 💔 Atrial Fibrillation (AF)

Pathophysiology

Chaotic, disorganized electrical activity in the atria (firing at 350–600 bpm) with irregular AV node conduction producing an irregularly irregular ventricular response.

ECG Changes

Absent P waves — replaced by irregular fibrillatory (f) waves, best seen in V1 and lead II
Irregularly irregular R-R intervals (the hallmark)
Narrow QRS (unless aberrant conduction or accessory pathway)
Variable ventricular rate (60–180 bpm depending on AV node)
No consistent PR interval

ECG Image — Atrial Fibrillation with Rapid Ventricular Response

Atrial Fibrillation — absent P waves, fine fibrillatory baseline, irregularly irregular narrow QRS complexes

Classic AF: no organized P waves, fine fibrillatory waves at baseline (best seen in V1), completely irregular R-R intervals with narrow QRS complexes — sinus rhythm is entirely absent.

5. 🚫 Complete (Third-Degree) AV Block

Pathophysiology

Complete failure of conduction through the AV node. Atria and ventricles beat independently — the atria at the sinus rate and the ventricles at a slow escape rate (junctional 40–60 bpm or ventricular 20–40 bpm).

ECG Changes

Complete AV dissociation — P waves and QRS complexes march independently
Regular P-P intervals (atrial rate ~70–90 bpm)
Slow, regular R-R intervals (escape rate 20–60 bpm)
Wide QRS if ventricular escape (≥120 ms); narrow QRS if junctional escape (above the His bundle)
P waves may appear before, within, or after QRS complexes — no fixed PR interval

ECG Image — Complete AV Block

Complete (Third-Degree) AV Block — complete AV dissociation, P waves march through at faster rate, wide QRS ventricular escape rhythm

Total AV dissociation: P waves occur at a faster independent atrial rate while wide QRS escape complexes occur slowly and independently — the "P waves marching through" pattern is the defining feature.

6. ⚡ Ventricular Tachycardia (VT)

Pathophysiology

A rapid ectopic ventricular focus or re-entry circuit within the ventricular myocardium generates a fast, life-threatening tachyarrhythmia. Most commonly seen with structural heart disease (post-MI scar, cardiomyopathy).

ECG Changes

Wide complex tachycardia — QRS ≥120 ms (often 140–200 ms)
Rate 100–250 bpm, regular
AV dissociation (P waves independent — definitive for VT)
Fusion beats and capture beats (pathognomonic when present)
Concordance in precordial leads (all positive = positive concordance; all negative = negative concordance) — strongly suggests VT
Extreme axis deviation ("no-man's land" — NW axis)

Brugada criteria: If LBBB morphology, any of the above features = VT.

ECG Image — Monomorphic Ventricular Tachycardia

Ventricular Tachycardia — wide complex tachycardia, positive concordance in precordial leads, no visible P waves, superior axis

Monomorphic VT: high-amplitude wide QRS complexes at rapid rate with positive concordance across precordial leads and superior axis — ectopic ventricular origin, often associated with structural heart disease.

7. 🌊 Wolff-Parkinson-White (WPW) Syndrome

Pathophysiology

An accessory pathway (Bundle of Kent) bypasses the AV node, pre-exciting part of the ventricle before the normal conduction system. This creates a characteristic delta wave and shortens the PR interval.

ECG Changes (Classic Triad)

Short PR interval (<120 ms) — conduction bypasses the AV node
Delta wave — slurred, slow upstroke at the start of QRS
Widened QRS (>120 ms total) — due to ventricular pre-excitation
Secondary ST-T changes — discordant to delta wave
Pseudo-infarction pattern — negative delta waves can mimic Q waves

Risk: During AF, impulses can conduct rapidly via the accessory pathway → very fast ventricular rates → ventricular fibrillation

ECG Image — WPW Syndrome

WPW Syndrome — short PR interval, prominent delta waves slurring QRS onset, widened QRS in multiple leads

Classic WPW triad: shortened PR interval (<120 ms), visible delta wave (slurred QRS upstroke), and widened QRS — prominent in II, III, aVF and V2–V6.

8. 💪 Left Ventricular Hypertrophy (LVH)

Pathophysiology

Chronic pressure overload (hypertension, aortic stenosis) or volume overload causes concentric or eccentric hypertrophy of the LV. Increased muscle mass generates higher voltage and delayed repolarization.

ECG Changes

High QRS voltage — Sokolow-Lyon criteria: S(V1) + R(V5 or V6) ≥35 mm; or Cornell criteria: R(aVL) + S(V3) >28 mm (men), >20 mm (women)
"Strain pattern" — ST depression + asymmetric T-wave inversion in I, aVL, V5–V6 (lateral leads)
Left axis deviation
Prolonged QRS/intrinsicoid deflection
Broad, notched P wave (P mitrale) — if associated left atrial enlargement
QRS complexes may overlap between adjacent leads on paper (Seamens sign)

ECG Image — LVH with Strain Pattern

LVH — high voltage QRS, ST depression and T-wave inversions in lateral leads V5–V6 (strain pattern), deep S waves in V1–V2

LVH with strain: tall R-waves in V5–V6 meeting Sokolow-Lyon criteria, with ST depression and asymmetric T-wave inversions in I, II, III, aVF, V5–V6 — typical of chronic hypertensive heart disease.

9. 🫁 Pulmonary Embolism (PE)

Pathophysiology

Massive PE causes acute right ventricular pressure overload (acute cor pulmonale). The RV dilates, shifts the interventricular septum, and creates characteristic but non-specific ECG changes.

ECG Changes

Sinus tachycardia (most common finding, ~70% of cases)
S1Q3T3 pattern — deep S in lead I, Q wave in III, inverted T in III (present in ~20%)
Right bundle branch block (complete or incomplete)
T-wave inversions in V1–V4 (right precordial leads) — right heart strain
Right axis deviation
P pulmonale (peaked P in II ≥2.5 mm) — right atrial enlargement
New AF may occur

ECG Image — Pulmonary Embolism with S1Q3T3

Pulmonary Embolism — S1Q3T3 pattern with deep S wave in lead I, Q wave in III, inverted T wave in III; sinus tachycardia

Classic acute PE pattern: annotated S1Q3T3 — prominent S wave in I, pathological Q wave in III, inverted T in III — with sinus tachycardia reflecting right ventricular strain.

10. ⏱️ Long QT Syndrome (LQTS) + Torsades de Pointes

Pathophysiology

Prolonged ventricular repolarization (congenital ion channel mutations or acquired: drugs, electrolyte disturbances) extends the QT interval, creating a vulnerable window for re-entrant arrhythmias — specifically the polymorphic VT called Torsades de Pointes (TdP).

ECG Changes

Prolonged QTc — corrected QT interval: >440 ms (men), >460 ms (women); dangerous at >500 ms
Abnormal T-wave morphology — broad, notched, bifid, or biphasic T-waves
T-wave alternans — beat-to-beat variation in T-wave amplitude/polarity (high-risk marker)
Torsades de Pointes — polymorphic VT with characteristic twisting of QRS complexes around the isoelectric line, triggered by a short-long-short sequence or R-on-T phenomenon
Bradycardia — often present in congenital forms (LQTS types 1 and 2)

QTc Correction (Bazett): QTc = QT / √RR (in seconds)

ECG Image — Long QT Syndrome with Torsades de Pointes

Long QT Syndrome with Torsades de Pointes — prolonged QTc 478 ms, transitioning to polymorphic VT with twisting QRS morphology

Panel (a) shows baseline sinus rhythm with prolonged QTc (478 ms). Panel (b) shows the transition into Torsades de Pointes — polymorphic VT with the characteristic "twisting" of QRS complexes around the isoelectric baseline.

Quick Reference Summary Table

#	Disease	Key ECG Feature	Rate/Rhythm
1	Anterior STEMI	Convex ST elevation V1–V4 + reciprocal changes	Sinus
2	Inferior STEMI	ST elevation II, III, aVF + ST depression I, aVL	Sinus
3	Acute Pericarditis	Diffuse concave ST elevation + PR depression	Sinus (tachy)
4	Atrial Fibrillation	No P waves, fine f-waves, irregularly irregular	Irregular
5	Complete AV Block	AV dissociation, P-rate > QRS-rate	Bradycardia
6	Ventricular Tachycardia	Wide QRS ≥120 ms, AV dissociation	100–250 bpm
7	WPW Syndrome	Short PR, delta wave, widened QRS	Sinus
8	LVH	High voltage, lateral strain pattern	Sinus
9	Pulmonary Embolism	Sinus tachy, S1Q3T3, right precordial TWI	Sinus (tachy)
10	Long QT / Torsades	Prolonged QTc >500 ms, twisting polymorphic VT	Variable

Clinical Note: ECG interpretation must always be correlated with clinical presentation, symptoms, and other investigations. These ECG patterns are teaching examples — real-world tracings may show incomplete or atypical features.Here's a complete breakdown of 10 common heart diseases with their ECG changes and real ECG images:

What's Covered:

#	Disease	Hallmark ECG Finding
1	Anterior STEMI	Convex ST elevation V1–V4, reciprocal depression, tombstone morphology
2	Inferior STEMI	ST elevation II, III, aVF; reciprocal changes in I, aVL
3	Acute Pericarditis	Diffuse concave (saddle-shaped) ST elevation + PR depression (differentiates from STEMI)
4	Atrial Fibrillation	No P waves → fine fibrillatory baseline, irregularly irregular R-R intervals
5	Complete AV Block	P waves and QRS march independently (AV dissociation), slow ventricular escape
6	Ventricular Tachycardia	Wide QRS ≥120 ms, AV dissociation, concordance in precordial leads
7	WPW Syndrome	Short PR + delta wave + widened QRS — the classic triad
8	LVH	High voltage (Sokolow-Lyon ≥35 mm) + lateral strain pattern (ST depression + T inversion)
9	Pulmonary Embolism	Sinus tachycardia + S1Q3T3 + right precordial T-wave inversions
10	Long QT / Torsades	QTc >500 ms + polymorphic VT with twisting QRS morphology

Each section includes the underlying mechanism, specific lead-by-lead ECG changes, a summary table, and an annotated real ECG image sourced from peer-reviewed medical literature. Let me know if you'd like a deeper dive into any specific condition, treatment implications, or ACLS algorithms!

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