- Electrical alternans is when consecutive QRS complexes alternate in height.
- The most important cause is massive pericardial effusion, in which the alternating QRS voltage is produced by the heart swinging backwards and forwards within a large fluid-filled pericardium.
Massive pericardial effusion (tamponade) produces a triad of:
- Low voltage
- Electrical alternans
- Electrical alternans secondary to massive pericardial effusion
- ECG BASICS – Waves, Intervals, Segments and Clinical Interpretation
- ECG CLINICAL CASES – Your favourite ECG’s placed in clinical context with a challenging Q&A approach
- ECG and Cardiology Eponymous Syndromes – Cheats guide to eponymous emancipation
- ECG Reference Sites on the WEB – the best of the rest
- Chan TC, Brady WJ, Harrigan RA, Ornato JP and Rosen PR. ECG in Emergency Medicine and Acute Care. Elsevier 2005
- Mattu A, Brady W. ECGs for the Emergency Physician 2, BMJ Books 2008.