gms | German Medical Science

Electrophysiogical detection of stress-induced myocardial ischemia is typically based on identifying changes in the repolarization phase, yet with limited accuracy. A new technology, which quantifies ischemic changes in the depolarization phase of the cardiac cycle (mid-QRS potentials) using analysis of high frequency components, was reported to better identify stress-induced ischemia. Question. Our aim was to test the performance of this technique in patients undergoing exercise myocardial perfusion SPECT (MPS). Methods. MPS was performed in 95 consecutive patients (age: 62±11 yo, 72 males) and used as the gold standard for ischemia. Conventional exercise ECG recording was combined with high resolution ECG acquisition, which was digitized and analyzed using the HyperQ™ System (BSP, Israel). The relative intensity change in high frequency mid-QRS components (HyperQ) during exercise was used as an index of ischemia. Results. Analysis was possible in 85 patients of whom 33 exhibited MPS ischemia. Ischemia was characterized by reduction in HyperQ intensity (see Figure 1 [Fig. 1]). The HyperQ index of ischemia was found more sensitive than the conventional ST analysis (76% vs 59%, p<0.01) and with better specificity (85% vs 57%, p<0.01). Conclusions. HyperQ analysis presents a significant improvement to current stress ECG in detecting ischemia and may thus aid in enhancing the non-invasive diagnosis of ischemic heart disease.