ECG Basics · Lesson 16 · Putting it together

Arrest rhythms, pacing and artifact

Electrical activity is not the same as a heartbeat that pumps blood. Read the trace, then state what remains unknown.

VF and electrical silence

The VF example has disorganised ventricular activity without repeating QRS complexes. The asystole example is electrically silent. In clinical cardiac arrest, AHA groups VF and pulseless VT as shockable rhythms, and asystole and PEA as nonshockable rhythms. Those categories need the arrest context, not just a screen label.

PEA is not a special waveform

Pulseless electrical activity means electrical activity without a detectable pulse. An organised ECG cannot prove circulation. This simulator has no perfusion or pulse model, so it cannot confirm PEA or return of spontaneous circulation.

Pacing: output, electrical capture, circulation

This pacing example is a separate demonstration of electrical capture, not an arrest treatment exercise.

A pacing spike indicates an electrical output. A resulting depolarisation is electrical capture; evidence of circulation is still needed to establish mechanical capture. Here the paced example illustrates electrical activation only.

Artifact can hide the rhythm

This engine example adds baseline movement and muscle noise to sinus rhythm. Artifact can obscure atrial activity or resemble a dangerous rhythm. Compare leads and signal quality with the patient's condition. Chest compressions also create ECG artifact; that specific source is not simulated here.

References

1. American Heart Association. Adult cardiac arrest algorithm, 2025. VF/pulseless VT and asystole/PEA categories.
2. American Heart Association. Adult Advanced Life Support, 2025. Wide-complex tachycardia, pacing capture and ECG artifact.

SIMULATED · NOT FOR DIAGNOSIS · TracingsMD ECG Basics

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