Give me 10 ecg changes with ecg example
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ECG changes examples with images STEMI LBBB hyperkalemia LVH atrial fibrillation
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ECG examples site:litfl.com OR site:ecglibrary.com 10 classic ECG patterns images
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site:litfl.com ECG atrial fibrillation STEMI hyperkalemia WPW QT prolongation images
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I have the killer rhythms infographic and comprehensive knowledge. Now I'll compose the full answer with the infographic plus detailed descriptions for each ECG change.
Here are 10 classic ECG changes with explanations and visual examples:
ECG Killer Rhythms Overview
(Infographic from LITFL ECG Library showing 8 killer patterns; full 10 covered below)
1. ST-Elevation Myocardial Infarction (STEMI)
What to look for:
- ST elevation ≥1 mm in ≥2 contiguous limb leads, or ≥2 mm in ≥2 contiguous precordial leads
- Reciprocal ST depression in opposite leads
- Hyperacute T waves (early sign) - broad, tall, symmetrical T waves
- Q waves develop over hours (sign of necrosis)
Territory clues:
- Inferior STEMI: ST elevation in II, III, aVF (right coronary artery)
- Anterior STEMI: ST elevation in V1-V4 (LAD)
- Lateral STEMI: ST elevation in I, aVL, V5-V6
ECG Example:
Clinical significance: Time-critical - door-to-balloon <90 min. - Tintinalli's Emergency Medicine
2. Atrial Fibrillation (AF)
What to look for:
- Absent P waves (replaced by fibrillatory baseline - "irregularly irregular" f-waves)
- Irregularly irregular R-R intervals (no two consecutive intervals the same)
- Ventricular rate typically 100-160 bpm if uncontrolled
- Narrow QRS complex (unless aberrant conduction or pre-existing bundle branch block)
ECG Example (from LITFL):
| Lead | Finding |
|---|---|
| All leads | No discernible P waves |
| Rhythm | Completely irregular |
| V1 | Fibrillatory baseline most visible |
Clinical significance: Risk of thromboembolism (stroke). CHA₂DS₂-VASc score guides anticoagulation.
3. Left Bundle Branch Block (LBBB)
What to look for:
- QRS duration ≥120 ms (broad complex)
- Broad notched ("M-shaped") R waves in lateral leads I, aVL, V5, V6
- Deep S waves in V1 (rS or QS pattern)
- Absence of septal Q waves in leads I, V5, V6
- Appropriate ST/T wave discordance (ST and T wave go opposite to main QRS deflection)
Memory aid: WiLLiaM - W shape in V1, M shape in V6 for LBBB
ECG Example:
Broad notched R in V6, deep S in V1, QRS >120 ms - see LITFL LBBB examples
Clinical significance: New LBBB with chest pain warrants urgent evaluation. Apply Sgarbossa criteria to detect underlying MI.
4. Hyperkalemia
What to look for (progressive with K⁺ level):
| K⁺ Level | ECG Change |
|---|---|
| 5.5-6.5 mmol/L | Tall, peaked ("tented") T waves - narrow base, symmetric |
| 6.5-7.0 mmol/L | Prolonged PR interval, widened QRS |
| 7.0-8.0 mmol/L | Loss of P waves, further QRS widening |
| >8.0 mmol/L | Sine wave pattern, VF, asystole |
As shown in the infographic above: tented T waves + QRS widening + prolonged PR are the hallmarks.
Clinical significance: Life-threatening above 7 mmol/L. Give calcium gluconate for cardiac membrane stabilization.
5. Wolff-Parkinson-White (WPW) Syndrome
What to look for:
- Short PR interval (<120 ms)
- Delta wave - slurred upstroke at the beginning of the QRS
- Broad QRS (>110 ms) due to fusion of delta wave and normal conduction
- Secondary ST/T wave changes (discordant from delta wave)
As shown in the infographic above: delta wave + short PR interval are the classic features.
Clinical significance: Risk of rapid conduction during AF - can precipitate VF. Avoid AV nodal blocking agents (adenosine, verapamil) in AF with WPW.
6. Pulmonary Embolism (PE)
What to look for:
- Sinus tachycardia (most common finding)
- S1Q3T3 pattern: deep S in lead I, Q wave + T wave inversion in lead III
- New right bundle branch block (RBBB) or incomplete RBBB
- T wave inversions in V1-V4 (right heart strain)
- Right axis deviation
- P pulmonale (peaked P waves in lead II >2.5 mm)
Clinical significance: ECG is neither sensitive nor specific for PE, but the combination of sinus tachycardia + S1Q3T3 + anterior T inversions supports the diagnosis. - Tintinalli's Emergency Medicine
7. Complete Heart Block (3rd Degree AV Block)
What to look for:
- P waves present but completely dissociated from QRS complexes
- P rate > QRS rate (atria and ventricles beat independently)
- Narrow QRS escape rhythm (junctional, rate 40-60 bpm) or wide QRS escape rhythm (ventricular, rate 20-40 bpm)
- Regular P-P intervals, regular R-R intervals, but no fixed PR interval
Clinical significance: Often requires emergency transvenous pacing. Causes include inferior MI (usually transient), Lyme disease, drug toxicity.
8. Brugada Syndrome
What to look for:
- Coved-type (Type 1 - diagnostic): J wave/ST elevation ≥2 mm with downsloping ST segment + T wave inversion in V1-V3
- Saddle-back type (Type 2/3 - not diagnostic alone)
- Appears spontaneously or unmasked by fever, sodium channel blockers, or vagotonic states
As shown in the infographic above: coved ST elevation >2 mm + negative T wave in V1-3 is the defining pattern.
Clinical significance: Risk of VF and sudden cardiac death. ICD is the main treatment for high-risk patients.
9. QT Prolongation / Torsades de Pointes
What to look for:
- Corrected QT interval (QTc) >440 ms (men), >460 ms (women) using Bazett's formula
- Giant T wave inversions can accompany QTc prolongation (seen in intracranial hemorrhage)
- Torsades de Pointes: polymorphic VT with QRS complexes that "twist" around the isoelectric baseline
Common causes:
- Drugs: antipsychotics (haloperidol, quetiapine), antibiotics (azithromycin, fluoroquinolones), antiarrhythmics (amiodarone, sotalol)
- Electrolyte disturbances: hypokalemia, hypomagnesemia, hypocalcemia
- Congenital Long QT syndrome
As shown in the infographic above: QT prolongation + giant T wave inversion point to intracranial pathology or drug toxicity.
Clinical significance: Torsades can degenerate to VF. Treat with IV magnesium sulfate 2g.
10. Left Ventricular Hypertrophy (LVH)
What to look for:
- Sokolov-Lyon criteria: S in V1 + R in V5 or V6 >35 mm (most used)
- Cornell criteria: R in aVL + S in V3 >28 mm (men), >20 mm (women)
- ST depression and T wave inversion in lateral leads (I, aVL, V5-V6) - "strain pattern"
- Left axis deviation
- Broad, notched P wave in lead II (P mitrale) - suggests left atrial enlargement
Clinical significance: Marker of end-organ damage from hypertension. Associated with increased risk of arrhythmias, heart failure, and MI.
Summary Table
| # | ECG Change | Key Feature | Cause |
|---|---|---|---|
| 1 | STEMI | ST elevation + reciprocal depression | Coronary occlusion |
| 2 | Atrial Fibrillation | No P waves, irregularly irregular | Multiple atrial foci |
| 3 | LBBB | WiLLiaM pattern, QRS >120 ms | Conduction disease, MI |
| 4 | Hyperkalemia | Peaked T waves → sine wave | Renal failure, drugs |
| 5 | WPW | Delta wave, short PR | Accessory pathway |
| 6 | Pulmonary Embolism | S1Q3T3, sinus tachycardia | RV strain |
| 7 | 3rd Degree AV Block | P-QRS dissociation | Ischemia, Lyme, drugs |
| 8 | Brugada Syndrome | Coved ST V1-V3 | Sodium channel mutation |
| 9 | QT Prolongation/TdP | QTc >440 ms, twisting VT | Drugs, electrolytes |
| 10 | LVH | Tall QRS voltages + strain | Hypertension, aortic stenosis |
For interactive ECG strips with real patient tracings, the LITFL ECG Library is the gold-standard free resource, covering all 10 patterns above with multiple annotated examples per diagnosis.
Create a visual ECG reference card (PDF) with all 10 patterns
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