This 36 year old normally well woman presented with an episode of chest pain radiating to her arm. Her ECG is as below:
Interpret her ECG- Rate: 60
- Rhythm: Sinus rhythm
- Axis: Normal
- Morphology: multiple morphology to p waves (bifid in p waves 1,2,3,5,6,8,9 downsloping in p waves 7,10, different complex in 4) u waves (seen most easily in V2)
- Intervals: PR 160 QRS 100 QTc 406
- Summary: Moving atrial focus
Clinical Relevance:
Seen when multiple ectopic foci within the atrium transmit an action potential to the ventricles.
Needs to be three different p wave morphologies to make diagnosis
Can be differentiated from multifocal atrial tachycardia by rate (moving atrial focus normally is around 60-100bpm, multifocal atrial tachycardia seen with rates of more than 100)
Generally benign and there is no specific treatment
Can be associated with
- underlying lung disease
- digoxin toxicity
- as a manifestation of sick sinus syndrome eg in the elderly
- increased vagal tone eg in young
Further Reading – Textbook:
Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.