Background. Electrocardiographic (ECG) changes during stress testing are a common and perplexing finding during non-ischaemic stress echocardiography (SE). Research has provided conflicting results regarding the implications. Methods. SE was performed after maximal Bruce protocol treadmill exercise. Results. 3020 consecutive patients, mean age 58±12 years, 36% female, were followed-up for up to 9 years (mean 36±21 months) post SE. Time to first cardiac event (composite of heart failure admission, worsening New York Heart Association class, worsening ejection fraction, acute coronary syndrome, revascularization, angina or cardiovascular death) was analyzed and adjusted using Cox proportional hazards regression. Prognostic significance was found with 1.5mm of downsloping or horizontal ST depression. Adjusting for baseline differences, increased risk of composite major adverse cardiac events was shown with at least 1.5mm of exercise induced ST depression (Hazard ratio [HR] of 2.47, 95% Confidence ratio [CI] 1.67-3.72, p<0.0001). Patients achieving high level exercise capacity (≥13 metabolic equivalents or METs) with ST depression lower risk of cardiac events during follow-up Conclusion. Patients with ST segment depression but non-ischaemic stress imaging have poorer prognosis compared to patients with non-ischaemic stress echocardiograms with normal stress ECGs. ST depression of 1.5mm or more was established as a prognostically significance value. High exercise capacity improves prognosis, and ECG changes in that setting can be regarded as false positives. Overall, however, ST depression during non-ischaemic stress imaging is not a benign finding.

Background: Stress echocardiography (SE) is an established technique for assessment of coronary artery disease (CAD) which is difficult to perform and interpret. Left ventricular stroke volume (SV) is readily estimated with Doppler echocardiography. It can be affected by myocardial ischemia, with possible adjunctive value during SE. Methods: Patients underwent Bruce protocol SE with SV estimated before and after maximal treadmill exertion post routine regional wall analysis. Incremental change in SV (ΔSV) with exercise was measured. Results: A derivation cohort (n=273) was established to test the hypothesis. An optimal cut-off for detection on inducible ischemia was ΔSV ≤ +10ml. The validation cohort of consecutive patients (n = 1093, 376 [34%] female; age 59±12 years) were followed clinically after SE for 20,460 patient-months. There were 1000 patients with non-ischemic SE, and 93 patients with studies suggestive of myocardial ischemia. Secondary analysis yielded 831 patients with a normal exercise response (ΔSV > +10ml) and 192 with an abnormal ΔSV ≤ +10ml. Time to first combined adverse cardiac event (composite of angina, acute coronary syndrome, cardiac revascularization, worsening New York Heart Association (NYHA) class, a reduction in EF, and cardiovascular death) was analysed and adjusted using Cox proportional hazards regression. The hazard ratio for an adverse event with an abnormal ΔSV response (≤10ml) was 10.3 (95% confidence intervals 5.6-19.1, p<0.0001). Conclusions: SV assessment during SE is feasible and readily performed. It is simple, practical and has incremental diagnostic and prognostic value when added to exercise regional wall motion analysis.