The Lab

Rhythms

Pre-Excited Atrial Fibrillation

Irregular rapid ventricular activation with beat-to-beat changes in QRS width, amplitude and fusion, slurred pre-excited upstrokes and secondary repolarization changes. No organized atrial contraction; mechanical pulses vary. Above 120 bpm, the teaching model adds progressively worse filling, lower BP/output and higher wedge pressure, especially with left-heart disease. The size of the response is illustrative, not a universal property of pre-excitation.

Overview

Open Clinical controls → Baseline vitals → Rhythm and choose Pre-Excited Atrial Fibrillation. The rate and atrial/ventricular timing follow this rhythm’s model.

Irregular rapid ventricular activation with beat-to-beat changes in QRS width, amplitude and fusion, slurred pre-excited upstrokes and secondary repolarization changes. No organized atrial contraction; mechanical pulses vary. Above 120 bpm, the teaching model adds progressively worse filling, lower BP/output and higher wedge pressure, especially with left-heart disease. The size of the response is illustrative, not a universal property of pre-excitation.

The disease state remains active. Disease morphology, treatment and temporary pacing can modify the displayed result; use the effective rate and the current twelve-lead read.

Step by step

  1. Select the rhythm, then adjust Ventricular rate if required.
  2. Compare Lead II, V1 and the arterial pulse.
  3. Open 12-lead ECG; use Variant or Next variant, then Pause → Interpretation.

References & further reading

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