Cardiac conduction and ECG
Surface electrocardiography records voltage changes arising from coordinated myocardial depolarization and repolarization.
Open interactive lesson & self-check ↗ECG components: representative beat
Original conceptual SVG · scalableIllustrative P–QRS–T waveform. Not calibrated, not a real lead tracing, not for ECG diagnosis.
Trace the conduction system
The sinoatrial node normally initiates impulses. Atrial depolarization precedes conduction through the AV node and the His–Purkinje system to the ventricles.
Read basic wave meaning
P wave: atrial depolarization. QRS complex: ventricular depolarization. T wave: ventricular repolarization.
Know common measurements conceptually
PR interval includes atrial conduction and AV delay. QT interval spans ventricular depolarization through repolarization and varies with heart rate.
Reference and next reading
Explore the original curriculum and publisher-hosted resources for full-depth reading; this note is an original schematic introduction, not an exhaustive chapter.