Significance of exercise induced U wave inversion as a marker for coronary artery disease

Exercise stress testing for detecting inducible ischaemia was first introduced in the 1950s and remained one of the only methods of stressing the heart for years to come. The presence of inducible ischaemia was assessed by ECG changes during exercise apart from other factors, namely, duration of exercise, blood pressure and heart rate response, metabolic equivalents achieved, etc. With the emergence of other tests to look for inducible ischaemia, for example, dobutamine stress echocardiography and myocardial perfusion scanning and also as the threshold for invasive evaluation has decreased, unusual and infrequently encountered ECG changes are not looked for during exercise stressing with the same degree of diligence. The authors describe below the case of a 49-year-old male whose left anterior descending artery stenosis was diagnosed on exercise stress test on the basis of a negative U wave.