Electrical alternans: a sign, not a diagnosis.

Area of Science:

• Cardiology
• Electrocardiography

Background:

• Electrical alternans is an electrocardiographic phenomenon characterized by varying QRS complex amplitude or axis.
• It is most frequently associated with large pericardial effusion and potential cardiac tamponade.

Purpose of the Study:

• To review the diverse etiologies and prognoses of electrical alternans.
• To emphasize electrical alternans as an electrocardiographic sign with a broad differential diagnosis.

Main Methods:

• Literature review of electrical alternans.
• Presentation of electrocardiogram examples.
• Discussion of potential mechanisms and clinical significance.

Main Results:

• Electrical alternans can occur in various clinical scenarios beyond pericardial effusion.
• The finding represents an electrocardiographic sign, not a standalone diagnosis.
• Etiologies and prognoses vary significantly.

Conclusions:

• Electrical alternans necessitates a comprehensive differential diagnosis.
• Further research is needed for less understood causes of this electrocardiographic sign.