Experimental Validation of Noninvasive Epicardial and Endocardial Activation Imaging

Abstract

We present results from a study in which endocardial and epicardial activation sequences, both for ventricular stimulated and for atrioventricular-conducted activation, were reconstructed from (pseudo) body surface potentials. The study consists of 2 parts. In part I, transmural activation mapping was © 2016 American Heart Association, Inc. Original Article Circ Arrhythm ElectrophysiolBackground-Noninvasive imaging of cardiac activation before ablation of the arrhythmogenic substrate can reduce electrophysiological procedure duration and help choosing between an endocardial or epicardial approach. A noninvasive imaging technique was evaluated that estimates both endocardial and epicardial activation from body surface potential maps. We performed a study in isolated and in situ pig hearts, estimating activation from body surface potential maps during sinus rhythm and localizing endocardial and epicardial stimulation sites. Methods and Results-From 3 Langendorff-perfused pig hearts, 180 intramural unipolar electrograms were recorded during sinus rhythm and ectopic activation, together with pseudo-body surface potential map ECGs in 2 of them. From 4 other anesthetized pigs, 64-lead body surface potential maps were recorded during sinus rhythm and ventricular stimulation from 27 endocardial and epicardial sites. The ventricular activation pattern was computed from the recorded QRS complexes. For both Langendorff-perfused hearts, the calculated epicardial and endocardial activation patterns showed good qualitative correspondence to the patterns obtained with needle electrodes. Absolute timing difference for sinus rhythm was 10±5 and 11±8 ms respectively, and for ectopic activation 6±5 and 7±6 ms, respectively. Calculated activation for the in situ hearts in sinus rhythm was similar to patterns recorded in Langendorff-perfused hearts. During stimulation, the distance between the stimulation site and calculated site of earliest activation was 18 (15-27) mm, and 23 of 27 stimulation sites were correctly mapped to either endocardium or epicardium. performed in Langendorff-perfused, isolated pig hearts, while recording pseudo body surface maps (BSMs) from the boundary of a fluid-filled container with integrated electrodes in which the heart was suspended. In part II, BSMs and catheter electrograms were recorded simultaneously in intact pigs. The data from part I were used to adapt our inverse method to porcine electrophysiology and to evaluate it using a simple, homogeneous volume conductor (ie, the fluid-filled container), with transmural activation mapping as a reference. However, BSMs are measured on the surface of the torso, which is irregularly shaped, and contains organs with low conductivity (eg, lungs) and blood with high conductivity. This will affect the current distribution within the thorax and, thereby, the potentials generated at the body surface. Therefore, experiments in intact adult pigs were used to show the ability of our noninvasive mapping technique to reliably determine ventricular activation and dis...

Validation and Opportunities of Electrocardiographic Imaging: From Technical Achievements to Clinical Applications

“…Technical validation encompasses a broad range of cardiac source models, forward model formulations, inverse methods, and pre- and post-processing techniques. These studies are typically executed using either analytical ( Rudy et al, 1979 ) or simulated potentials ( Dubois et al, 2016 ; Figuera et al, 2016 ; Svehlikova et al, 2018 ), ex vivo torso tank experiments ( Oster et al, 1997 ; Shome and Macleod, 2007 ; Bear et al, 2018a ) and in vivo animal studies ( Liu et al, 2012 ; Oosterhoff et al, 2016 ; Cluitmans et al, 2017 ; Bear et al, 2018b ), with more limited results from humans ( Ghanem et al, 2005 ; Sapp et al, 2012 ; Erem et al, 2014 ; Schulze, 2015 ; Punshchykova et al, 2016 ). For simplicity, here we have organized technical validation according to the different features that may be extracted from ECGI, irrespective of source models.…”

“…Electrograms are one of the most common features reconstructed with ECGI, as they provide useful information to clinicians, directly relatable to invasive recordings. Ground truth data is available through simulations ( Simms and Geselowitz, 1995 ; Wang et al, 2010 ; Figuera et al, 2016 ; Janssen et al, 2017 ), recordings obtained with epicardial, endocardial and transmural electrode arrays (with upwards of 200 electrodes) in ex vivo ( Oster et al, 1997 ; Shome and Macleod, 2007 ; Bear et al, 2018b ) and in vivo ( Zhang et al, 2005 ; Han et al, 2011 ; Liu et al, 2012 ; Oosterhoff et al, 2016 ; Cluitmans et al, 2017 ; Bear et al, 2018b ) experimental models, and invasive mapping clinically ( Ghanem et al, 2005 ; Sapp et al, 2012 ; Punshchykova et al, 2016 ). Most validation studies to date use a global evaluation of the QRS, T, or QRS-T waveform reconstruction using correlation and/or error metrics, to demonstrate the accuracy in the overall topology and/or amplitude of electrograms (example in Figure 3 ).…”

“…Over the past four decades, ECGI has seen considerable development, from purely analytical studies ( Rudy et al, 1979 ; Figuera et al, 2016 ; Svehlikova et al, 2018 ), to torso tank ( Oster et al, 1997 , 1998 ; Ramanathan and Rudy, 2001 ; Shome and Macleod, 2007 ; Bear et al, 2018a ) and large animal models ( Liu et al, 2012 ; Oosterhoff et al, 2016 ; Cluitmans et al, 2017 ; Bear et al, 2018b ) and finally application in humans ( Ghanem et al, 2005 ; Horáček et al, 2011 ; Haissaguerre et al, 2014 ; Schulze, 2015 ; Punshchykova et al, 2016 ). It is now increasingly used for academic research and in clinical practice.…”

Validation of Noninvasive Epi- Endocardial Electrocardiographic Imaging Accuracy Using Right Ventricular Endocardial Pacing

“…В основе лежит реконструкции электрограмм на трехмерных анатомических моделях сердца по данным многоканальной регистрации ЭКГ и мультиспиральной компьютерной (МСКТ) или магнитно-резонансной томографии (МРТ). Исследованию точности данной методики посвящен ряд работ нескольких научных групп [1][2][3][4][5][6][7][8]. Однако в доступных нам опубликованных данных отсутствует информация о результатах верификации НЭФК на эпикардиальной и эндокардиальной поверхности желудочков сердца с детальным анализом влияния совокупности факторов (клиническими параметрами, МСКТ с учетом качества построения трехмерных моделей сердца, параметрами стимуляции и характеристиками выбранных для анализа фрагментов ЭКГ, включая количество поверхностных ЭКГ электродов на торсе) на используемые алгоритмы решения обратной задачи.…”

Clinical Evaluation of Noninvasive ECGI Epi-Endocardial Mapping Accuracy

“…Noninvasive ElectroCardioGraphic Imaging (ECGI) in combination with CT or MRI for obtaining precise heart and torso geometries is a method that allows to electrically map endocardial and epicardial surfaces. Although some available noninvasive ECGI systems are mapping the epicardial surface only, few studies have been performed to validate the accuracy of a novel epi-endocardial ECGI mapping technology [1,2]. Nevertheless, the lack of a detailed results description of the epi-/endocardial accuracy limits further integration of this technology into the clinical practice.…”