explaun me 10 commomheart diseases with ECG changes and ECG images

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ECG changes myocardial infarction ST elevation

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atrial fibrillation ECG irregular rhythm absent P waves

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left ventricular hypertrophy ECG high voltage criteria

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complete heart block third degree AV block ECG

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Wolff-Parkinson-White syndrome ECG delta wave short PR

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pulmonary embolism ECG S1Q3T3 right heart strain sinus tachycardia

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ventricular tachycardia ECG wide complex tachycardia

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pericarditis ECG diffuse ST elevation PR depression

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hyperkalemia ECG peaked T waves wide QRS sine wave

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dilated cardiomyopathy ECG low voltage bundle branch block poor R wave progression

I now have comprehensive ECG images for all 10 conditions. Let me compile the full educational response.

10 Common Heart Diseases with ECG Changes

1. ST-Elevation Myocardial Infarction (STEMI)

Pathophysiology: Complete occlusion of a coronary artery → transmural ischemia → progressive myocyte necrosis.

ECG Changes:

Hyperacute T-waves (earliest sign — tall, broad, peaked)
ST-segment elevation ≥1 mm in ≥2 contiguous limb leads, or ≥2 mm in ≥2 contiguous precordial leads (convex/"tombstone" morphology)
Reciprocal ST depression in opposing leads
Pathological Q waves (>40 ms wide, >25% of R-wave height) — develop within hours to days indicating necrosis
T-wave inversion in the evolving/resolving phase

Territory localization:

Territory	Leads with STE	Culprit artery
Anterior	V1–V4	LAD
Lateral	I, aVL, V5–V6	LCx
Inferior	II, III, aVF	RCA
Posterior	Tall R + ST↓ in V1–V3	RCA/LCx

Acute Anterolateral STEMI — ST elevation V1–V6 with reciprocal depression inferiorly

Inferior + Posterior STEMI — ST elevation II, III, aVF with tall R waves and ST depression V1–V3

2. Atrial Fibrillation (AF)

Pathophysiology: Disorganized electrical activity in the atria replaces coordinated sinus node depolarization, producing chaotic atrial activation and irregularly irregular ventricular conduction.

ECG Changes:

Absent P waves — replaced by fine fibrillatory (f) waves best seen in V1
Irregularly irregular R-R intervals (hallmark finding)
Narrow QRS complexes (unless aberrant conduction or bundle branch block)
Rate varies: controlled (<100 bpm), rapid ventricular response (>100 bpm), or slow (in nodal disease)

Atrial fibrillation — absent P waves, irregularly irregular rhythm, rapid ventricular response

3. Complete (Third-Degree) AV Block

Pathophysiology: Total failure of conduction through the AV node or His-Purkinje system → complete atrioventricular dissociation. The ventricles are driven by a slow escape rhythm.

ECG Changes:

Complete AV dissociation — P waves and QRS complexes march independently
Regular P-P intervals at a faster atrial rate
Regular R-R intervals at a slower ventricular escape rate (20–40 bpm if ventricular; 40–60 bpm if junctional)
Wide QRS (>120 ms) if infra-Hisian escape; narrow QRS if junctional escape
No consistent PR interval — P waves appear before, within, or after QRS complexes

Third-degree AV block — P waves and QRS complexes completely dissociated, wide ventricular escape rhythm

4. Acute Pericarditis

Pathophysiology: Inflammation of the pericardium → epicardial irritation → diffuse myocardial surface injury current. Evolves through 4 ECG stages over weeks.

ECG Changes (Stage I — acute):

Diffuse concave ("saddle-shaped") ST elevation in all leads except aVR and V1
PR-segment depression in most leads (very specific — reflects atrial injury)
PR elevation in aVR (reciprocal)
Spodick's sign — downsloping TP segment
No reciprocal ST depression (unlike STEMI) — key distinguishing feature

Key differentiator from STEMI: Diffuse distribution across multiple vascular territories; concave (not convex) ST morphology; PR depression.

Acute pericarditis — diffuse concave ST elevation, PR depression in lead II, PR elevation in aVR

5. Left Ventricular Hypertrophy (LVH)

Pathophysiology: Chronic pressure or volume overload (hypertension, aortic stenosis) → concentric or eccentric hypertrophy → increased myocardial mass → greater electrical voltage.

ECG Changes:

High QRS voltage: Sokolow-Lyon criteria: S in V1 + R in V5 or V6 ≥35 mm; Cornell criteria: R in aVL + S in V3 >28 mm (men), >20 mm (women)
Left axis deviation
"Strain pattern": ST depression + T-wave inversion in lateral leads (I, aVL, V5–V6) — indicates subendocardial ischemia from increased oxygen demand
Prolonged QRS duration (not frank LBBB)
Left atrial enlargement (P mitrale — broad, notched P in II)

LVH with strain — high voltage in precordial leads, ST depression and T-wave inversions in lateral leads (V5–V6)

6. Pulmonary Embolism (PE)

Pathophysiology: Acute pulmonary arterial obstruction → sudden rise in right ventricular afterload → right ventricular strain and dilation → clockwise cardiac rotation.

ECG Changes (most common: sinus tachycardia ± non-specific ST-T changes):

Sinus tachycardia (most frequent finding)
S1Q3T3 pattern (McGinn-White sign): Deep S wave in lead I + Q wave in lead III + T-wave inversion in lead III
Right bundle branch block (complete or incomplete)
T-wave inversions V1–V4 (right ventricular strain)
Right axis deviation
P pulmonale (peaked P in II — right atrial enlargement)
Low voltage if massive PE

Note: The classic S1Q3T3 is present in only ~20% of PE cases. Sinus tachycardia alone is the most common finding.

Pulmonary embolism — S1Q3T3 with right ventricular strain pattern, sinus tachycardia, T inversion V1–V3

7. Wolff-Parkinson-White (WPW) Syndrome

Pathophysiology: Congenital accessory pathway (Bundle of Kent) bypasses the AV node → pre-excitation of the ventricle occurs before the normal His-Purkinje system fires → delta wave and short PR. Risk of life-threatening arrhythmias (AF with rapid conduction through the accessory pathway).

ECG Changes (sinus rhythm — pre-excitation pattern):

Short PR interval (<120 ms)
Delta wave — slurred, slow upstroke at the onset of QRS
Widened QRS (>120 ms) due to fusion of pre-excited and normally conducted beats
Secondary ST-T changes (discordant to the delta wave/QRS)
"Pseudo-infarction" Q waves in inferior leads with negative delta waves (type B pattern)

Accessory pathway localization by delta wave polarity in limb and precordial leads.

WPW syndrome — short PR interval, prominent delta waves, widened QRS complexes

8. Ventricular Tachycardia (VT)

Pathophysiology: Rapid ventricular depolarization originating below the His bundle — most commonly from re-entry circuits around myocardial scar (ischemic cardiomyopathy), triggered activity, or abnormal automaticity.

ECG Changes:

Wide QRS complex tachycardia (>120 ms) at rate >100 bpm (usually 140–220 bpm)
AV dissociation — P waves visible but independent of QRS (pathognomonic when present)
Fusion beats and capture beats (confirms AV dissociation)
Positive or negative QRS concordance across precordial leads
QRS axis: Northwest axis (−90° to ±180°) strongly suggests VT
Brugada criteria and Vereckei criteria used to differentiate from SVT with aberrancy

Ventricular tachycardia — wide complex tachycardia, no visible P waves, monomorphic QRS morphology

9. Hyperkalemia

Pathophysiology: Elevated extracellular potassium depolarizes resting membrane potential → progressive conduction slowing → fatal arrhythmias if untreated. ECG evolves with rising K⁺ levels.

ECG Changes (progressive with rising K⁺):

Serum K⁺	ECG Change
5.5–6.5 mEq/L	Tall, narrow-based, peaked ("tented") T waves — earliest sign
6.5–7.5 mEq/L	PR prolongation, P-wave flattening/disappearance
7.5–8.5 mEq/L	QRS widening (intraventricular conduction delay)
>8.5 mEq/L	Sine-wave pattern (QRS and T merge), ventricular fibrillation, asystole

Severe hyperkalemia — peaked T waves, QRS widening, sine-wave morphology, K⁺ = 9.2 mEq/L

10. Dilated Cardiomyopathy (DCM)

Pathophysiology: Ventricular dilation and systolic dysfunction (reduced EF) from ischemic, idiopathic, viral, toxic, or genetic causes → diffuse myocardial fibrosis → conduction system disease and chamber enlargement.

ECG Changes:

Left bundle branch block (LBBB) — most characteristic finding; indicates His-Purkinje fibrosis
Poor R-wave progression across precordial leads (V1–V4)
Low voltage QRS in limb leads (infiltration/fibrosis)
Pathological Q waves mimicking prior infarction (ischemic DCM)
Left atrial enlargement (broad, notched P mitrale)
Sinus tachycardia (compensatory)
Atrial fibrillation (common complication)
Ventricular ectopy / non-sustained VT

Dilated cardiomyopathy pattern — low voltage, poor R-wave progression, bundle branch block, atrial enlargement

Quick Reference Summary Table

#	Condition	Key ECG Finding
1	STEMI	Convex ST elevation + reciprocal depression + Q waves
2	Atrial Fibrillation	No P waves, irregularly irregular RR
3	Complete Heart Block	AV dissociation, slow escape rhythm
4	Acute Pericarditis	Diffuse concave ST↑, PR depression
5	LVH	High voltage + lateral strain pattern
6	Pulmonary Embolism	Sinus tachycardia, S1Q3T3, RV strain
7	WPW Syndrome	Short PR + delta wave + wide QRS
8	Ventricular Tachycardia	Wide QRS tachycardia, AV dissociation
9	Hyperkalemia	Peaked T waves → sine wave
10	Dilated Cardiomyopathy	LBBB, poor R progression, low voltage

Sources: Harrison's Principles of Internal Medicine 22E (2025); Tintinalli's Emergency Medicine; Ganong's Review of Medical Physiology; Lippincott Illustrated Reviews: Pharmacology. ECG images from peer-reviewed clinical literature.

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