An unusual ECG deflection: Fact or artifact?

Peculiar electrocardiographic findings are not unusual and upon careful review can often be clarified. We present a case of an 85 year-old woman with no previous cardiac history, incidentally discovered high grade atrioventricular block, and a puzzling electrocardiographic complex of unclear etiology which defies reasonable physiological explanations. The finding resembled a tiny QRS in a perfectly regular R-R interval following only non-conducted P-waves. The patient declined further work-up, so a definite cause could not be determined, but based on history, complex morphology, and inability to reproduce or explain the findings, we were compelled to accept the finding as an artifact.