Explain me 10 common heart disease and with ecg changes with ecg images those diseases
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ECG changes myocardial infarction ST elevation
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atrial fibrillation ECG electrocardiogram
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heart block complete AV block ECG third degree
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ventricular tachycardia ECG wide complex
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left bundle branch block ECG LBBB
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Wolff-Parkinson-White syndrome delta wave ECG WPW
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hypertrophic cardiomyopathy ECG left ventricular hypertrophy
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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 Torsades de Pointes ECG
Here is a comprehensive guide to 10 common heart diseases with their ECG changes and real ECG images:
10 Common Heart Diseases: ECG Changes & Images
1. 🫀 ST-Elevation Myocardial Infarction (STEMI)
Pathophysiology: Complete occlusion of a coronary artery → transmural ischemia → necrosis.
ECG Changes:
| Phase | Changes |
|---|---|
| Hyperacute (minutes) | Peaked, tall "hyperacute" T-waves |
| Acute (hours) | Convex ("tombstone") ST elevation ≥1 mm in ≥2 contiguous leads |
| Evolving | Q-wave formation, T-wave inversion |
| Old/Chronic | Pathological Q-waves, T-wave normalization |
- Anterior STEMI (LAD): ST elevation in V1–V6, reciprocal depression in II, III, aVF
- Inferior STEMI (RCA/LCx): ST elevation in II, III, aVF; reciprocal depression in I, aVL
- Lateral STEMI: ST elevation in I, aVL, V5–V6
- Posterior STEMI: Tall R wave + ST depression in V1–V3 (mirror image)
ECG Image — Acute Anterolateral STEMI (LAD occlusion):
ECG Image — Acute Inferior + Posterior STEMI (RCA/LCx):
2. 💓 Atrial Fibrillation (AF)
Pathophysiology: Chaotic, disorganized atrial electrical activity from multiple re-entrant circuits → loss of organized atrial contraction.
ECG Changes:
- Absent P waves — replaced by irregular fibrillatory (f) waves, best seen in V1 and lead II
- Irregularly irregular R-R intervals — hallmark finding
- Narrow QRS (unless aberrant conduction/WPW)
- Ventricular rate 100–180 bpm if uncontrolled (tachycardic AF) or <100 bpm if rate-controlled
- No consistent PR interval
ECG Image — Atrial Fibrillation with Rapid Ventricular Response:
3. 🔴 Complete (Third-Degree) AV Heart Block
Pathophysiology: Total failure of impulse conduction from atria to ventricles through the AV node → complete AV dissociation. Requires pacemaker.
ECG Changes:
- Complete AV dissociation — P waves and QRS complexes fire independently
- P waves: Regular at faster atrial rate (e.g., 70–80 bpm)
- QRS complexes: Slow escape rhythm (20–50 bpm)
- Wide QRS (>120 ms) if ventricular escape focus; narrow if junctional escape
- Fixed, slow ventricular rate — bradycardia
- P waves "march through" QRS complexes and T-waves
ECG Image — Complete (Third-Degree) AV Block:
4. ⚡ Ventricular Tachycardia (VT)
Pathophysiology: Rapid ventricular depolarization from an ectopic ventricular focus, often in the setting of structural heart disease (post-MI scar, cardiomyopathy).
ECG Changes:
- Wide QRS tachycardia (QRS ≥120 ms) at rate >100 bpm (usually 150–250 bpm)
- AV dissociation — P waves independent of QRS (diagnostic if seen)
- Fusion beats and capture beats — pathognomonic when present
- Positive or negative concordance across precordial leads
- Brugada criteria / Vereckei algorithm used to differentiate from SVT with aberrancy
- Regular, monomorphic rhythm (monomorphic VT) or twisting morphology (polymorphic VT / Torsades)
ECG Image — Monomorphic Ventricular Tachycardia:
Note: If image above doesn't render, see below alternate:
5. 🌊 Left Bundle Branch Block (LBBB)
Pathophysiology: Failure of conduction through the left bundle branch → right-to-left ventricular depolarization → widened QRS with characteristic morphology. Associated with cardiomyopathy, CAD, hypertension.
ECG Changes (William Morrow mnemonic: WiLLiaM):
- QRS ≥120 ms (broad)
- Lead V1: Deep, broad S-wave (QS or rS pattern) — negative deflection
- Lead V6/I/aVL: Broad, monophasic R-wave (often notched/slurred "M" shape)
- No septal Q waves in V5–V6 (loss of septal activation)
- Discordant ST-T changes — ST/T opposite to QRS direction (secondary changes)
- New LBBB in acute chest pain = treat as STEMI equivalent (Sgarbossa criteria)
ECG Image — Left Bundle Branch Block:
6. ✨ Wolff-Parkinson-White Syndrome (WPW)
Pathophysiology: Accessory conduction pathway (Bundle of Kent) bypasses the AV node → ventricular pre-excitation. Risk of sudden death if AF conducts rapidly via accessory pathway.
ECG Changes (Classic Triad):
| Feature | Finding |
|---|---|
| Short PR interval | <120 ms (bypasses AV node delay) |
| Delta wave | Slurred upstroke at beginning of QRS |
| Wide QRS | >120 ms (fusion of normal + pre-excitation) |
- Secondary ST-T changes (discordant to delta wave direction)
- Pseudo-infarct patterns (negative delta waves can mimic Q waves)
- Pathway localization by delta wave polarity across leads
- Paroxysmal SVT / AVRT common clinical presentation
ECG Image — Wolff-Parkinson-White Syndrome (Classic Delta Waves):
7. 💪 Hypertrophic Cardiomyopathy (HCM)
Pathophysiology: Sarcomere gene mutations → asymmetric septal hypertrophy → LV outflow obstruction, diastolic dysfunction, myofiber disarray → risk of sudden cardiac death (especially in young athletes).
ECG Changes:
- Left ventricular hypertrophy (LVH) — high voltage QRS (Sokolow-Lyon: S V1 + R V5/V6 ≥35 mm)
- Deep "giant" T-wave inversions — especially V2–V5 in apical HCM (Yamaguchi syndrome); deep symmetric
- Strain pattern — ST depression + T inversion in lateral leads (I, aVL, V5–V6)
- Absent septal Q waves in lateral leads (due to septal hypertrophy reversing normal septal activation)
- Left axis deviation
- Wide QRS if significant hypertrophy with conduction delay
- Abnormal ECG found in >95% of HCM patients
ECG Image — HCM with Giant T-wave Inversions (Apical Variant):
ECG Image — HCM comparison (Concentric vs Septal vs Apical):
8. 🔥 Acute Pericarditis
Pathophysiology: Inflammation of the pericardium → epicardial injury currents → diffuse ST changes (unlike STEMI which is territorial). Causes: viral (most common), autoimmune, post-MI (Dressler's), uremia.
ECG Changes (4 Classic Stages):
| Stage | Timing | ECG Findings |
|---|---|---|
| Stage 1 | Days 1–2 | Diffuse concave ("saddle-shaped") ST elevation in all leads except aVR + V1; PR depression |
| Stage 2 | Week 1 | ST normalizes, PR depression persists |
| Stage 3 | Week 2 | Diffuse T-wave inversion |
| Stage 4 | Weeks–months | ECG normalizes |
Key differentiating features from STEMI:
- Diffuse (not territorial) ST elevation
- PR segment depression (most specific sign) — best in II, most leads; aVR shows reciprocal PR elevation
- Spodick's sign — downsloping TP segment
- No reciprocal ST depression (except in aVR/V1)
- No Q-waves
ECG Image — Acute Pericarditis (Saddle-shaped ST elevation + PR depression):
9. 🫁 Pulmonary Embolism (PE)
Pathophysiology: Thrombus in pulmonary vasculature → acute right ventricular pressure overload → RV strain → specific ECG pattern. Most common ECG finding is simply sinus tachycardia.
ECG Changes:
| Finding | Significance |
|---|---|
| Sinus tachycardia | Most common finding (70%) |
| S1Q3T3 pattern | S wave in I + Q wave in III + T inversion in III — classic but only 20% sensitive |
| Right axis deviation | RV strain |
| RBBB (complete or incomplete) | Acute RV dilation stretches right bundle |
| T-wave inversions V1–V4 | Anterior RV strain pattern |
| P pulmonale | Peaked P waves — right atrial enlargement |
| AF / atrial flutter | Occasionally seen |
ECG Image — Pulmonary Embolism (S1Q3T3 pattern):
ECG Image — PE with RBBB + S1Q3T3:
10. ⏱️ Long QT Syndrome (LQTS) / Torsades de Pointes
Pathophysiology: Prolonged ventricular repolarization (genetic channelopathies — KCNQ1, KCNH2, SCN5A; or acquired via drugs, electrolytes) → increased dispersion of refractoriness → risk of Torsades de Pointes (TdP) → VF → sudden cardiac death.
ECG Changes:
| Feature | Details |
|---|---|
| Prolonged QTc | >440 ms (men) / >460 ms (women); critical risk >500 ms |
| T-wave abnormalities | Broad-based, notched, or biphasic T-waves (subtype-specific morphology) |
| U waves | Prominent U waves (LQT2) — can fuse with T-wave |
| T-wave alternans | Beat-to-beat variation in T-wave amplitude/polarity — sign of electrical instability |
| Torsades de Pointes | Polymorphic VT with "twisting" QRS complexes around isoelectric line, initiated by short-long-short sequence |
- LQT1: Broad smooth T-wave
- LQT2: Notched/bifid T-wave, prominent U-waves
- LQT3: Late-appearing, narrow T-wave with long isoelectric ST segment
ECG Image — Long QT Syndrome → Torsades de Pointes:
ECG Image — Torsades de Pointes initiation:
Quick Reference Summary Table
| # | Disease | Key ECG Feature |
|---|---|---|
| 1 | STEMI | Convex ST elevation (territorial) + reciprocal changes + Q waves |
| 2 | Atrial Fibrillation | Absent P waves + irregularly irregular rhythm |
| 3 | Complete AV Block | AV dissociation — P waves ≠ QRS, slow escape rhythm |
| 4 | Ventricular Tachycardia | Wide QRS tachycardia + AV dissociation |
| 5 | LBBB | Wide QRS + deep S in V1 + broad R in V6, discordant ST-T |
| 6 | WPW Syndrome | Short PR + delta wave + wide QRS (pre-excitation triad) |
| 7 | Hypertrophic CM | LVH + giant T inversions + absent lateral Q waves |
| 8 | Acute Pericarditis | Diffuse saddle-shaped ST elevation + PR depression |
| 9 | Pulmonary Embolism | Sinus tachycardia + S1Q3T3 + RV strain pattern |
| 10 | Long QT / TdP | Prolonged QTc + T-wave abnormalities → Torsades de Pointes |
Clinical Pearl: The ECG is always interpreted in clinical context. A single finding rarely makes a diagnosis — combine rhythm, morphology, intervals, and lead distribution with the patient's presentation for accurate interpretation.
ECG images sourced from peer-reviewed clinical literature (PMC) and Harrison's Principles of Internal Medicine, 21st Edition.
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