Background and Objectives The study examined mirror changes in inferior wall myocardial infarction and its relationship with coronary lesions in non-infarcted areas using angiographic and electrocardiographic findings. Methods This retrospective study analyses 270 patients with inferior wall myocardial infarction, 135 of whom had mirror changes, and 135 had no. The patients' electrocardiograms, echocardiography results, and angiography results were examined. Ejection fraction, thrombolytic response, coronary artery occlusion, occlusion rate, and the number of occluded vessels were evaluated in two patients with and without mirror changes. Results We found no significant relationship between mirror changes and lateral arteries (P = 0.091). The findings indicated a connection between ST-segment depression and the existence of stenosis in the irresponsible vessel (P = 0.026). Also, in those patients exhibiting ST-segment depression, the degree of stenosis was more pronounced in the responsible vessel (P = 0.003). Additionally, no relationship was reported between multi-vessel involvement and ST-segment depression (P = 0.462). There was a noteworthy relationship between ST-segment depression and thrombolytic response (P = 0.002). Moreover, the results indicated that there was no substantial correlation between the EF level and the occurrence of ST-segment depression (P = 0.209). Conclusion It seems that mirror change in the ST segment plays a role in the severity of responsible vessel occlusion and the significance of irresponsible vessel occlusion. Mirror change did not affect EF level, though it influenced thrombolytic responses.