Animated 12-Lead ECG & Rhythm Visualizer
ECG Lead II — synchronized
Speed
⌨ Space · → step · ↑↓ lead · J/K rhythm · ? help
📏 Measure —
Task 1/4 —
drag the two calipers
Δ —
Heart Rate
—
bpm
PR Interval
—
ms
QRS Duration
—
ms
QTc (Bazett)
—
ms
Layout
Lead II — rhythm strip
Focus
What is this rhythm?
0 / 0 correct
Clinical Cases
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Accuracy
—
Streak
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Confidence
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Timed block:
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Step 1
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Step 1 Q-Bank
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ECG Quick Reference — Step 1
Intervals
PR: 120–200 ms · QRS: <120 ms · QTc ♂ <440 ms · QTc ♀ <460 ms · >500 ms = TdP risk
QTc Bazett
QTc = QT ÷ √(RR in sec)
Action Potential Phases
0 = fast Na⁺ in (upstroke) · 1 = Ito K⁺ out (notch) · 2 = ICaL (plateau) · 3 = IKr/IKs K⁺ out (repol) · 4 = If pacemaker only
STEMI Territories
Inferior (II,III,aVF) = RCA · Anterior (V1–V4) = LAD · Lateral (I,aVL,V5–V6) = LCx · Posterior (STD V1–V3 + tall R) = LCx/RCA
Antiarrhythmic Classes
IA (quinidine): Na⁺ + K⁺ block → QRS + QT ↑ · IC (flecainide): Na⁺ only → QRS ↑ QT same · III (amiodarone,sotalol): K⁺ → QT ↑ · IV (verapamil): Ca²⁺ → slow AV node
Long QT Syndromes
LQT1: KCNQ1 (IKs↓) → swimming · LQT2: KCNH2 (IKr↓) → noise/alarm · LQT3: SCN5A (INa↑) → sleep/bradycardia
AV Blocks
1°: PR >200 ms, all conduct · 2° Mobitz I: progressive PR → drop (AV node, narrow) · 2° Mobitz II: fixed PR → sudden drop (infra-His, WIDE → PPM!) · 3°: P/QRS dissociated
Electrolytes
Hyper K⁺: peaked T → wide QRS → sine wave · Hypo K⁺: flat T + U waves · Hypo Ca²⁺: long ST segment (phase 2) · Digoxin: scooped ST (Salvador Dalí mustache)
SRS Mastery Intervals
Box 1 → 1 day · Box 2 → 3 days · Box 3 → 7 days · Box 4 → 14 days · Box 5 (★) → 30 days
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