Noninvasive electrocardiographic imaging for cardiac electrophysiology and arrhythmia

Abstract

Over 7 million people worldwide die annually from erratic heart rhythms (cardiac arrhythmias), and many more are disabled. Yet there is no imaging modality to identify patients at risk, provide accurate diagnosis and guide therapy. Standard diagnostic techniques such as the electrocardiogram (ECG) provide only low-resolution projections of cardiac electrical activity on the body surface. Here we demonstrate the successful application in humans of a new imaging modality called electrocardiographic imaging (ECGI), which noninvasively images cardiac electrical activity in the heart. In ECGI, a multielectrode vest records 224 body-surface electrocardiograms; electrical potentials, electrograms and isochrones are then reconstructed on the heart's surface using geometrical information from computed tomography (CT) and a mathematical algorithm. We provide examples of ECGI application during atrial and ventricular activation and ventricular repolarization in (i) normal heart (ii) heart with a conduction disorder (right bundle branch block) (iii) focal activation initiated by right or left ventricular pacing, and (iv) atrial flutter.Disruptions of the regular heart rhythm, called cardiac arrhythmias, constitute a major cause of death and disability among the world's population. Although modern medicine relies heavily on noninvasive imaging modalities such as CT or magnetic resonance imaging to guide therapy, an equivalent modality for imaging cardiac arrhythmias is not yet available. Noninvasive diagnosis of arrhythmias is currently based on the standard 12-lead ECG, which involves measuring electric potentials from very few points on the body surface. Taken far away from the heart, these measurements lack sensitivity (may fail to detect abnormal activity) and specificity (may fail to accurately classify the arrhythmia or determine its location). Here we describe ECGI 1 , a new noninvasive imaging modality for cardiac electrophysiology and arrhythmias. This technique images potentials, electrograms and activation sequences (isochrones) on the epicardium, the outer surface of the heart. The ECGI methodology used in the human studies presented here builds on 20 years of development in our laboratory (Fig. 1). Many aspects of the approach were tested and validated experimentally in normal and abnormal canine hearts 2-7 . Building on these animal studies, we recently developed ECGI for human application. In this report we describe the first ECGI application in human subjects using our current imaging methodology.

Computer Three‐Dimensional Anatomical Reconstruction of the Human Sinus Node and a Novel Paranodal Area

“…The leading pacemaker site can, however, move spontaneously along the terminal crest of the right atrium, a phenomenon known as the wandering pacemaker. In open heart surgery, patients and in healthy individuals, the leading pacemaker site has been shown to be located anywhere along the terminal crest between the openings of the superior and inferior caval veins (Boineau et al, 1988;Ramanathan et al, 2004;Ramanathan et al, 2006). Such findings are in agreement with studies on smaller mammals.…”

Feasibility and Accuracy of Cardiac Magnetic Resonance Imaging–Based Whole‐Heart Inverse Potential Mapping of Sinus Rhythm and Idiopathic Ventricular Foci

“…The first ventricular epicardial breakthrough was located at the right ventricular free wall and corresponded with descriptions in the literature 1, 12. Furthermore, it was also possible to visualize abnormal ventricular activation patterns such as a right bundle branch block (Video S1).…”

2012 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation: Recommendations for Patient Selection, Procedural Techniques, Patient Management and Follow-up, Definitions, Endpoints, and Research Trial Design

“…224,225 Another system that has been developed to noninvasively map rotational activity is the ECGI mapping system. 221,570,571,572 This system utilizes a multielectrode vest that records 224 body surface ECGs; electrical potentials, electrograms, and isochrones are then reconstructed on the heart’s surface using geometrical information from computed tomography (CT). A mathematical algorithm combines the body surface potentials recorded by the electrodes and the geometric information provided by CT and solves the electrocardiographic inverse problem in order to noninvasively obtain estimated epicardial electrograms.…”

“…A mathematical algorithm combines the body surface potentials recorded by the electrodes and the geometric information provided by CT and solves the electrocardiographic inverse problem in order to noninvasively obtain estimated epicardial electrograms. 221, 570 An advantage of this approach is that it is noninvasive, and thus can be used to provide detailed follow-up information on AF recurrence. Disadvantages of the system are that it is limited to providing virtual electrograms of the atrial epicardium; activity on the interatrial septum, the PV-LAA ridge, etc., is not recorded.…”