An unusual electrocardiogram artifact in a patient with near syncope.

Electrocardiogram (ECG) artifacts are common and should be known by every physician. Although usual ECG artifacts can be identified by their clinical context, morphology, and dissociation with underlying normal cardiac rhythm, one may encounter with examples that closely imitate serious disorders. Here, we report an unusual ECG artifact mimicking several serious disorders, which is very exceptional because of its clinical importance, morphology, and association with normal rhythm.