Quantifying Alterations Over Time in ST-Segment/T-Wave Amplitudes During Elective Percutaneous Coronary Intervention.

In this work, we evaluate the inter-patient magnitude of electrocardiography (ECG) alterations over time during ischemia. The freely available STAFF III database provides 12-lead ECG recordings of patients before, during, and after elective percutaneous coronary intervention (PCI), where a coronary vessel is widened with a balloon inflation. Patients undergoing this procedure often do not show standard ECG findings and thereby cannot be assessed by the subject-independent and absolute thresholds defined in clinical guidelines. We compute alterations of ST-segment and T-wave amplitudes w.r.t. QRS amplitude over time for each patient and lead. We demonstrate that quantifying these relative amplitudes changes over time is feasible in standard and non-standard ECG recordings. To demonstrate clinical relevance, we use the features for differentiating N=54 patients with atherosclerotic plaque in either the right coronary artery (RCA) or left anterior descending (LAD). Results show significant differences in five leads for ST-segment alterations and three leads for T-wave alterations, which are also suggested by clinical guidelines for ischemia detection.