What does electrical alternans indicate in a cardiac patient?

Electrical alternans is a phenomenon observed in the electrocardiogram (ECG) where there is a variation in the amplitude or morphology of the QRS complexes, typically with a regular pattern. This can occur in conditions like pericardial effusion or cardiac tamponade, where the heart's position varies due to fluid surrounding it. As the heart beats, the fluid alters the electrical pathway, leading to a fluctuation in the electrical signal's strength.

The presence of electrical alternans often serves as an important clinical sign indicating underlying pathophysiology, particularly concerning the heart's mechanical stability and rhythm. Understanding this phenomenon helps clinicians recognize serious conditions that may require prompt intervention or further diagnostic imaging, making it crucial for cardiac assessment.

Other options do not capture the significance of electrical alternans. For instance, it does not indicate a stable heart rhythm, as the very variability suggests instability; it does not imply an increased heart rate, nor does it confirm consistent QRS morphology. These distinctions are essential for recognizing diagnoses based on ECG findings effectively.