The negative U wave in unstable angina : Prevalence, coronary and ventricular correlations, diagnostic value : Noninvasive cardiology

Aim. To evaluate the prevalence and diagnostic value of U wave inversion during angina. Methods. Ninety-two consecutive patients admitted to the coronary care unit for unstable angina were enrolled. Coronary angiography was performed in 19 of 21 patients with transitory U wave inversion. None had angina during the procedure. A scoring system was adopted to quantify the coronary status. Results. Negative U waves occurred in 23.9%, and were second only to ST depression as a sign of ischemia. Angiography showed high rates of severe multivessel disease, of collateral circulation and of kinetic changes, as well as high coronary scores, indicating extensive myocardial involvement. Conclusions. The findings indicate a higher prevalence of U wave inversion during ischemia than usually reported. They also confirm the correlation between U wave inversion and extensive myocardial involvement and support the hypothesis that a negative U wave may be a sign of altered ventricular compliance. Clinical Implications. A negative U wave is not always easily detectable; clinicians should therefore look carefully for it, as its presence increases the diagnostic power of electrocardiography.