The Challenge of Hidden Ischemia: A Case of Negative Dobutamine Stress Echocardiography and Positive Treadmill Test: A Case Report

Background Dobutamine Stress Echocardiography (DSE) and Exercise Stress Test (EST) are widely used non-invasive modalities for assessing myocardial ischemia. Case Description A 56-year-old male with stable angina pectoris underwent DSE, revealed a negative ischemic response, however, ST- segment depression (V3-V6) was observed during peak stress. Ejection fraction improved from 49–60% with persistent hypokinetic motion in the mid-inferolateral segment. Subsequently, a treadmill test using Modified Bruce Protocol was performed and terminated at 5:04 minutes due to chest pain and achieved 79% of maximal age-predicted heart rate (MAPHR). The test revealed ST-segment elevation in aVR (2.5 mm) and upsloping ST-segment depression in lead V6 approaching a peak exercise, along with a hypotensive response. Downsloping ST segment depressions were revealed in lead V6 (1.5 mm) and V3-V4 (2 mm) at 2 minutes of recovery, returning to baseline at 8 minutes recovery. The patient exhibited a functional capacity of 3.44 METs and a high-risk Duke Treadmill Score. Coronary angiography revealed 2 vessel disease with Chronic Total Occlusion (CTO) at Left circumflex (LCx) Conclusion Hidden ischemia may obscure regional abnormalities on DSE while still eliciting electrical and hemodynamic changes on EST. Studies show that patients with akinetic segments supplied by CTO who do not exhibit recovery during dobutamine infusion are likely to have nonviable myocardium, with significant correlations found between negative responses. A lack of contractile reserve during the test suggests that the myocardial segments are nonviable. The exercise stress tests provide essential complementary diagnostic parameters regarding ischemia, functional capacity and risk stratification. Dobutamine Stress Echocardiography is effective in distinguishing viable myocardium from irreversibly damaged tissue