BackgroundExercise is a physiologic stress that helps the physicians to clarify the presence or absence of cardiovascular disease which may be obscure at rest. Although it is sensitive, its specificity is affected by several parameters, such as some metabolic conditions, some structural heart diseases, and some baseline electrocardiogram abnormalities. Currently, the relationship between coronary dominance and accuracy of EET is not examined. Therefore, this study was conducted to determine the potential impact of coronary dominance on the accuracy of EET.MethodsIn this retrospective study, data were gathered from 720 patients from four medical centers. The pattern of dominancy was determined, and the coronary dominance pattern of the patients who had normal angiograms despite abnormal EETs was compared to that from all the patients.ResultsAmong the patients who had a normal angiogram despite an abnormal EET, 27% were left dominant while the frequency of left dominancy in the whole population of the study was only 10.9% (P = 0.013). There were no significant differences in baseline characteristics, such as age and sex, between the two studied groups.ConclusionThe results indicated that the presence of left dominance in patients who had normal angiograms despite an abnormal EET was significantly higher than general population. Therefore, left dominance may be considered a confounding factor for EET, producing false positive results.