419 The use of ST/HR Hysteresis as a Diagnostic Tool During Treadmill Exercise Stress Echo

Abstract

Exercise stress test limitations including relatively low reported sensitivity has prompted research into analysis methods beyond traditional ST-segment depression criteria. ST/HR hysteresis has demonstrated relatively higher diagnostic accuracy as acknowledged by the American Heart Association Scientific Statement (2013). The aim of the present study is to assess the sensitivity and specificity of ST/HR Hysteresis for identifying CAD within a large tertiary referral centre. Data from Exercise Stress Echo (ESE) reports performed at a large tertiary referral centre between October 2017 and May 2018 (n=318) analysed retrospectively. Uninterpretable ECGs (n=24), bundle branch blocks (n=40) , and those with “non-diagnostic” ESE reports (n=33) excluded. ST/HR Hysteresis values calculated via GE-CASE Stress System (leads aVL, aVR, V1 excluded). Positive hysteresis was based on a partition value of ≥0.015mV and compared against a reference test of stress echo to determine sensitivity and specificity. Identification of ‘CAD’ for the purpose of analysis was based upon a positive ESE displaying a new inducible wall-motion abnormality. 225 tests remained after exclusions (24 positive, 201 negative) Both positive ESE and hysteresis occurred in 18 cases (sensitivity-=75%). Of 201 negative tests, 123 displayed negative hysteresis (specificity=62%). ST/HR hysteresis used during ESE does not display superior sensitivity and specificity within this population compared to that of traditional ST-segment criteria reference values. Further research is required using ECG-only based EST, ideally with coronary angiography as the reference test, to explore the potential utility of ST/HR Hysteresis as a diagnostic tool.