The negative U wave in the setting of demand ischemia

To the Editor: We thank Drs. Venkatachalam and Rimmerman¹ for their Clinical Picture article, “Electrocardiography in aortic regurgitation: It’s in the details,” in the August 2011 issue. This was very interesting, as usual for the Cleveland Clinic Journal of Medicine.

The maxim that “a negative U wave is never normal,” first noted about 50 years ago, still holds true. However, the authors’ statement on page 506—ie, that a negative U wave indicates structural heart disease—is too restrictive, since ischemia is not always due to a structural problem. Functional ischemia from excess demand, such as from tachycardia, sepsis, or gastrointestinal bleeding, can also cause negative U waves.^2,3 The broader comment in the “sidebar” on page 505 could be considered to include demand ischemia, but for clarity, it would be helpful to state this explicitly.