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ECG library

Low voltage with tachycardia

advanced

A 61-year-old with metastatic breast cancer, progressively breathless, with a strangely 'quiet' ECG.

25 mm/s · 10 mm/mV · synthetic tracing
100%
IIIIIIaVRaVLaVFV1V2V3V4V5V6
II (rhythm)
Calipers:2000 ms50.0 small boxes30 bpm if R-RDrag the orange markers. One small box = 40 ms.

Key findings

  • QRS amplitudes low in every lead
  • Sinus tachycardia
  • The combination, in the right story, points at fluid around the heart

Learning points

  • Low voltage plus tachycardia in a cancer or post-viral patient is an echocardiogram TODAY: tamponade is a diagnosis you must go looking for.
  • The insulation differential for low voltage: pericardial fluid, obesity, emphysema, myxedema, and infiltrative myocardium (amyloid).
  • Electrical alternans (beat-to-beat QRS height swing) is the more specific cousin; its absence excludes nothing.

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