Abstract 818: A Novel Electrophysiological Model Using Hybrid X-Ray/MRI and Non-Contact Mapping to Estimate Electrical Recruitability of Myocardial Tissue
Introduction CRT is established therapy for patients with symptomatic heart failure, poor LV function & evidence of dyssynchrony.
Hypothesis CRT outcomes may be improved by understanding of patient-specific conduction through electrical recruitability (ER) maps of the LV which can be derived from LV electrical activation (EA) data & electrophysiology (EP) models.
Methods Patients scheduled for CRT underwent cardiac MRI in our hybrid X-ray/MRI (XMR) laboratory to delineate scar using late gadolinium enhancement (LE). An EP study was performed in the same procedure. An Eikonal EP model was used to predict propagation wavefronts in different pacing modes. ER was defined as the square of the tissue space constant of EA & was estimated by an adaptive algorithm by matching the simulated to the recorded activation times. Activation maps were recorded in various pacing modes using non-contact mapping (NCM).
Results Ten patients underwent combined MRI & EP study. Fig 1a⇓ shows the estimated ER for a patient with activation recorded in sinus rhythm (SR) & corresponding % thickness LE from cardiac MRI (Fig 1b⇓). The correspondence of low recruitability areas (blue) to positive LE areas is evident. Further, an endocardial paced isochronal map was then predicted using the EP model with the SR ER map (Fig 1c⇓) & compared against NCM isochrones obtained (Fig 1d⇓) pacing in that position.
Conclusion We have shown the proof of concept for estimating the electrical recruitability of myocardial tissue. Such maps may provide insights into the electrical properties of the tissue and assist in prediction of activation patterns resulting from pacing and may have a role in optimization of CRT pacing lead positions.