See the Block, See the Beat

Simulate a drug or target. Learn the science. Practice it.

Pick a drug

Class

Drug

Show

Action potential

Fast · ventricledrug

Slow · SA / AV nodedrug

faint dashed = normal trace · ✕ = blocked channel phase 0 · Na⁺ → QRS phase 2 · Ca²⁺ → plateau / PR phase 3 · K⁺ → T wave / QT

Surface ECGdrugzoom

QRS = Na⁺ T wave = K⁺ PR = Ca²⁺

Every heartbeat starts as one electrical signal that always takes the same path. Watch it light up each part in turn — that order is exactly what the ECG is drawing.

SA node

Atria

AV node

Ventricles

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Turns ON · depolarize · Na in · Turns OFF · repolarize · K out

tap a stage to jump

tap a phase to jump

Drug	Class	Blocks	ECG effect	Heart rate

Class I subtypes

Class I	Binds	Comes off	Effect
IA	both states	medium	wider QRS, longer QT
IB	inactivated only	fast	shorter QT, QRS unchanged
IC	both states	slow	much wider QRS

Class	Drugs	Effect on ECG

Rhythm	ECG tell	Manage

Why they happen

Mechanism	What happens

Rhythm A

Rhythm B

Layout

Zoom

—

See the block. See the beat.

Pick a drug

Shape the intervals

Select a target

Action potential

Surface ECGdrugzoom

Build a practice set

Set complete

Pick a drug

Shape the intervals↺ Reset

Select a target

Action potential

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Build a practice set

Set complete

Shape the intervals

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