The value of exercise-induced U-wave inversion on ECG chest wall mapping in the identification of individual coronary arterial lesions.

Exercise-induced U-wave inversion on chest wall mapping was compared with coronary arteriographic findings in 160 consecutive patients who presented with chest pain suggestive of ischaemic heart disease. ECG recordings were made from 16 points on the chest wall before, during and after exercise. None of the 27 patients with normal coronary arteriograms developed U-wave inversion during or after exercise (specificity = 100%). In 21 (all males) of the 133 patients (15.8%) with significant coronary arterial lesions, U-wave inversion on exercise was noticed on different coronary artery territories on the chest wall map, and its localization was correlated with angiographic evidence of individual coronary arterial lesions (100% projection rate). In 9 patients (6.8%) this sign was observed in the absence of any ST segment changes or Q waves. Exercise-induced U-wave inversion was the sole ECG criterion reflecting a lesion of the left anterior descending artery in 12 cases (9%), of the circumflex in 6 cases (4.5%), and in only one case of right coronary artery disease. This sign was not detectable in the conventional V5 site in 9 cases (7.1%) with significant disease of the left anterior descending coronary artery. These nine patients showed U-wave inversion on other areas of the left anterior descending coronary artery territory on exercise. Exercise-induced U-wave inversion disappeared in all the ten patients who underwent coronary artery bypass graft surgery. It is suggested that exercise-induced U-wave inversion shown on chest wall mapping is a reliable indicator of coronary artery disease, which disappears after myocardial revascularization, and in addition, aids identification of individual coronary arterial lesions.