Principal Component-Referenced Multipolar Mapping to Localize an Arrhythmic Source From Various Depths of the
Nathan Denham1, Stéphane Massé1, Yusuf Abderrahman1
1University of Toronto, Toronto, Ontario, Canada.
Background:
Intramural premature ventricular contraction (PVC) mapping is limited by the ability of unipolar and bipolar electrograms (EGMs) to discriminate near from far-field activity.
Objectives:
In this study, the authors hypothesized that multipolar EGMs with improved far-field rejection would provide superior source detection.
Methods:
A Langendorff perfused healthy swine heart model was utilized in which a left ventricular free wall PVC was generated using a variable depth plunge needle. EGMs were recorded from the ventricular surface using either a customized array (n = 5) or the OPTRELL catheter in CARTO (n = 6). A comparison of unipolar vs multipolar EGM morphology, amplitude, width, and timing was performed for the predictive accuracy of source location. In silico modeling of outflow tract PVCs assessed localization with dual surface mapping.
Results:
Multipolar EGMs produced a smaller percentage of QS morphology on the array compared with unipolar EGMs irrespective of depth (6 mm: 9 ± 5 vs 49 ± 10; 5 mm: 6 ± 5 vs 56 ± 20; 4 mm: 9 ± 7 vs 61 ± 20; 3 mm: 7 ± 2 vs 50 ± 25; P < 0.001). A multipole QS had a positive likelihood ratio of 8.0% (95% CI: 5.5%-11.7%) of being adjacent to the source and a non-QS EGM had a 95% (95% CI: 94%-96%) specificity of being remote to the source. Local activation annotation with multipolar EGMs produced maps with a single early focus, in contrast to unipolar maps, which showed a diffuse breakout pattern with multiple early areas.
Conclusions:
Multipolar EGMs are superior to unipolar EGMs in predicting the location of a PVC, reflected by a smaller area of QS morphology and narrowing down the diffuse breakout of early activation.
