Real-ECG extraction and stroke volume from MR-Compatible 12-lead ECGs; testing during stress, in PVC and in AF patients
KeywordsStroke Volume Atrial Fibrillation Patient Processing Block Vary Heart Rate Subject Result
Due to the Magneto-Hydro-Dynamic (MHD) effect, blood flow within the MRI’s magnetic field (B0) produces a large voltage during the S-T cardiac segment . The peak MHD voltage (VMHD) can be comparable, in higher-field MRIs, to the R-wave amplitude of the real Electrocardiogram (ECGreal), so that VMHD reduces ECG-gating reliability and prevents ischemia-monitoring during cardiac imaging/interventions. We hypothesized that (1) separation of ECGreal and VMHD from 12-lead ECGs acquired within a 1.5T MRI could be achieved, using adaptive filtering, based on a set of ECG calibration measurements, and (2) a non-invasive beat-to-beat stroke-volume estimation could be achieved from time-integrated systolic VMHD.
The filtering extracts ECGreal from measured 12-lead ECG, preserving ECGreal for ischemia monitoring and MRI gating. Stroke volume can be non-invasively derived from the time-integrated systolic VMHD.
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