Electrocardiographic Imaging for Cardiac Arrhythmias and Resynchronization Therapy

Helder Pereira; Steven Niederer; Christopher A. Rinaldi

Europace. 2020;22(10):1447-1462.

Abstract and Introduction

Abstract

Use of the 12-lead electrocardiogram (ECG) is fundamental for the assessment of heart disease, including arrhythmias, but cannot always reveal the underlying mechanism or the location of the arrhythmia origin. Electrocardiographic imaging (ECGi) is a non-invasive multi-lead ECG-type imaging tool that enhances conventional 12-lead ECG. Although it is an established technology, its continuous development has been shown to assist in arrhythmic activation mapping and provide insights into the mechanism of cardiac resynchronization therapy (CRT). This review addresses the validity, reliability, and overall feasibility of ECGi for use in a diverse range of arrhythmias. A systematic search limited to full-text human studies published in peer-reviewed journals was performed through Medline via PubMed, using various combinations of three key concepts: ECGi, arrhythmia, and CRT. A total of 456 studies were screened through titles and abstracts. Ultimately, 42 studies were included for literature review. Evidence to date suggests that ECGi can be used to provide diagnostic insights regarding the mechanistic basis of arrhythmias and the location of arrhythmia origin. Furthermore, ECGi can yield valuable information to guide therapeutic decision-making, including during CRT. Several studies have used ECGi as a diagnostic tool for atrial and ventricular arrhythmias. More recently, studies have tested the value of this technique in predicting outcomes of CRT. As a non-invasive method for assessing cardiovascular disease, particularly arrhythmias, ECGi represents a significant advancement over standard procedures in contemporary cardiology. Its full potential has yet to be fully explored.

Introduction

Cardiovascular disease (CVD) is the leading cause of death in Western countries,^[1] and imposes a severe burden on society. While many advanced non-invasive measurement technologies have been developed, the 12-lead electrocardiogram (ECG) has been in use for over 100years and has become established as the 'de facto standard' for the non-invasive assessment of a wide range of heart diseases. The ability to obtain numerical readings of electrical measurements of the heart has long helped healthcare professionals provide both prevention and treatment.

Despite being a powerful diagnostic tool, 12-lead ECG has some limitations when used to support management procedures in modern cardiology. The current pool of research has established that 12-lead ECG is limited in detecting the precise location of arrhythmias, or detailed electrical activation pattern when cardiac resynchronization therapy (CRT) is involved.^[2,3] Further drawbacks include its limited value in precisely identifying atrial and ventricular activation during arrhythmias, including accessory atrioventricular conduction activation,^[4] and in providing a detailed assessment of electrical ventricular activation abnormalities,^[5] inadequate pinpointing of the location of ventricular tachycardia (VT),^[6] and poor spatial resolution.^[7] These limitations may necessitate invasive electrophysiological studies to understand the patient's underlying conditions.

Electrocardiographic imaging (ECGi) is a non-invasive, multi-lead ECG-type imaging tool (50 to approximately 300 electrodes depending on the manufacturer) that allows 3D visualization of the cardiac geometry with onset activation maps providing further diagnostic data compared to a conventional 12-lead ECG.^[2,4,8] It has been shown to be accurate for detecting a broad spectrum of specific arrhythmic characteristics.^[3] This novel method may be able to address the limitations of 12-lead ECG. This review addresses the validity, reliability, and overall feasibility of ECGi for use in a diverse range of arrhythmias.

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Europace. 2020;22(10):1447-1462. © 2020 Oxford University Press
Copyright 2007 European Heart Rhythm Association of the European Society of Cardiology (ESC). Published by Oxford University Press. All rights reserved.

Table 1. Summary of studies
Author	Study type	Population	Intervention	Comparison	Conclusion
Knecht 2017³³	Clinical study	118 patients with continuous AF duration <1 year	ECVUE™ 252 electrodes CardioInsight	None	Successful identification of biatrial AF drivers
Haissaguerre 2014³⁴	Clinical study	103 consecutive patients with persistent AF	ECVUE™ 252 electrodes CardioInsight	12-lead ECG	ECGi detects AF driver domains and provides results similar to ECG of ablation with shorter radiofrequency delivery
Gage 2017³⁵	Clinical study	66 patients undergoing CRT	ECGi 53 electrodes Medtronic	None	Potential improvement in selection and optimization of patients receiving CRT
Shah 2013³⁶	Clinical study	52 patients with ATs	ECGi 252 electrodes CardioInsight	CARTO or NavX	Successful and accurate identification of mechanism and location of AT
Erkapic 2015₃₇	RCT	42 patients with monomorphic PVCs with or without monomorphic VT	ECVUE™ 252 electrodes CardioInsight	12-lead ECG algorithms	Precise VA mapping and more targeted ablation with higher radiation exposure due to CT
Johnson 2017³⁸	Clinical study	40 CRT-indicated patients	53-electrode body-surface mapping Heartscape Technologies	Catheter-based assessment	Better identification of haemodynamically optimal sites for lead location
Ploux 2013³⁹	Clinical study	33 CRT candidates with LBBB and non-specific intraventricular conduction disturbance	ECVUE™ 252 electrodes CardioInsight	12-lead ECG	ECGi provides ventricular electrical uncoupling that can provide improved prediction of CRT clinical response
Zhang 2015⁴⁰	Clinical study	31 patients: 25 patients with BrS and 6 patients with RBBB	ECGi 250 electrodes CardioInsight	None	ECGi could differentiate BrS from RBBB
Revishvili 2015⁴¹	Clinical study	29 patients with cardiomyopathy and implanted CRT	NEEES 224 electrodes EP Solutions SA	CARTO 3	Correct highly accurate identification of the pacing site from various endo- and epicardial sites
Cakulev 2013⁴	Clinical study	27 patients with WPW, PVC, AT, AF	ECVUE™ 250 electrodes CardioInsight	Clinical Diagnoses	Valid activation sequence mapping in different types of arrhythmias
Cochet 2014²	Clinical study	27 patients with VT, WPW, AF, VF	ECGi 252 electrodes CardioInsight	None	ECGi may contribute to a more comprehensive assessment of various types of arrhythmias, improving diagnosis, therapy, and prognosis
Ghosh 2011⁴²	Clinical study	25 non-ischaemic cardiomyopathy patients who were previously implanted with a CRT device	ECGi 250 electrodes CardioInsight	None	Through ED, ECGi characterizes different important patterns of CRT responders in native and synchronized periods
Wang 2011²¹	Clinical study	25 patients undergoing catheter ablation procedures for various forms of VT with or without PVCs	ECGi 256 electrodes BioSemi	catheter-based electrophysiology mapping	Accurate mapping of the VT activation sequence, depth of origin, and location
Vijayakumar 2014⁴³	Clinical study	25 patients with genotype- and phenotype-positive LQTS	ECGi 256 electrodes CardioInsight	None	ECGi reveals important characteristics in LQTS patients, which are not detected by conventional ECG.
Jamil-Copley 2014⁶	Clinical study	24 patients with OTVT/PVC	ECGi 252 electrodes CardioInsight	12-lead-ECG algorithms	Catheter ablation can be improved with ECM that accurately determines the origin of OTVT and PVC
Cuculich 2011⁴⁴	Clinical study	24 patients with VT and history of MI	ECGi 256 electrodes BioSemi	None	Successful identification of areas of anatomic scar with ECGi
Wissner 2017⁴⁵	Clinical study	20 patients with monomorphic PVCs or VT	NEEES 224 electrodes	CARTO 3	Accurate identification of the PVC/VT site
Andrews 2017⁴⁶	Clinical study	20 genotyped ARVC patients with a broad spectrum of disease	ECGi 256 electrodes ActiveTwo BioSemi	None	ECGi provides characteristic properties of electro-physiological substrate in ARVC patients
Berger 2011⁴⁷	Clinical study	20 patients 10 patients with CHF undergoing CRT and 10 patients without structural heart disease	NICE 65 electrodes	None	NICE allows the visualization of endocardial and epicardial ventricular activation patterns, which can help to identify CRT responders with improved lead placement
Misra 2018⁴⁸	Clinical study	20 patients presenting for catheter ablation of VT or PVC	ECGi 12-lead ECG VIVO	CARTO	Earliest activation of VA
Ghosh 2008⁴⁹	Clinical study	14 paediatric patients with WPW syndrome and no other congenital disease	ECGi 200 electrodes CardioInsight	12-lead ECG-based algorithm	Successful localization of ventricular insertion sites of accessory pathways and evaluation of the outcomes
Yu 2018⁵⁰	Clinical study	13 patients with PVC	ECGi 208 electrodes BioSemi	CARTO 3	Excellent performance in localizing the initial sites of focal VA
Varma 2015⁵¹	Clinical study	11 patients with HF and LBBB after CRT implantation	ECGi	None	ECGi may lead to a more personalized approach and enhancement of CRT response
Potyagaylo 2019⁵²	Clinical study	10 patients with previously implanted CRT devices	ECGi 240 electrodes FRA + DTW	FRA	Reduced localization error and a significant accuracy improvement for clinical data of CRT patients with a complex aetiology
Silva 2009⁵³	Clinical study	8 paediatric heart-failure patients with CHD undergoing evaluation for CRT	ECGi 250 electrodes CardioInsight	None	ECGi was used to assess ventricular ED and identify candidates for CRT among paediatric patients and help with correct lead placement
Jia 2006⁵⁴	Clinical study	8 patients undergoing CRT during native rhythm and various pacing modes	ECGi 224-electrodes CardioInsight	None	ECGi provided important insights reflecting underlying pathologies
Tsyganov 2018⁸	Clinical study	8 patients with ischemic and non-ischemic cardiomyopathy and inducible ventricular arrhythmias	NEEES 224 electrodes	None	ECGi successfully visualizes macro-re-entrant circuits in scar-related VT
Berger 2006⁵⁵	Clinical study	7 patients with WPW syndrome undergoing catheter ablation of the accessory pathway	NICE 65 electrodes	CARTO	NICE localized the sites of origin of ventricular pre-excitation in patients with WPW syndrome, similar to CARTO
van Dam 2013⁵⁶	Clinical study	7 patients with PVCs	ECGi 12 lead ECG	None	Accurate PVC localization
Cuculich 2010²³	Clinical study	6 patients with a history of AF	ECGi 256 electrodes CardioInsight	CARTO	Effective and patient-specific mapping of epicardial activation patterns in patients with AF
Cuculich 2017⁵⁷	Clinical study	5 patients with high-risk, refractory VT undergoing SBRT	ECGi 256 electrodes BioSemi	None	ECGi can improve radioablation therapy and reduce the burden of VT
Wang 2018⁵⁸	Clinical study	4 patients with scar-related VT	ECGi 120 electrodes	None	ECGi mapping may provide improved information about arrhythmogenic substrates and better visualization of 3D re-entry circuits
Sapp 2012⁵⁹	Clinical study	4 patients undergoing epicardial catheter mapping and ablation of VT	ECGi 120 electrodes	None	Accurate identification of epicardial VT pacing sites and ventricular activation sequences
Wang 2011⁶⁰	Clinical study	4 patients referred for ablation associated with myocardial infarction	ECGi 120 electrodes	CARTO	Accurate quantification of the scar substrate and capturing abnormal EP patterns
van Dam 2016⁶¹	Clinical study	3 patients with symptomatic idiopathic PVCs	ECGi 12-lead ECG	None	Correct identification of the PVC origin
van Dam 2009⁶²	Clinical study	3 patients: 1 with WPW, 1 with BrS, and 1 healthy subject	ECGi 64 electrodes	None	The inversely estimated timing agreed with available physiological knowledge
Wang 2016⁶³	Clinical study	2 patients undergoing catheter ablation of scar-related VT	ECGi 120 electrodes	None	Potential improvement of the spatial construct of a re-entry circuit
Intini 2005⁶⁴	Case report	An athlete with focal VT	ECGi 224 electrodes	None	ECGi mapping guidance of the diagnosis and therapy of VT
Haissaguerre 2013⁶⁵	Case report	A patient with persistent AF for 7 months	ECGi 252 electrodes CardioInsight	None	Successful identification of active sources, such as rotors and PV foci, validated by ablation results
Zhang 2013⁶⁶	Case report	A patient with non-ischaemic cardiomyopathy, reduced LV, and VT	ECGi 252 electrodes CardioInsight	None	ECGi can successfully guide the diagnosis and treatment of VT
Schulze 2017⁶⁷	Case report	A patient with a sustained monomorphic VT	ECGi 51 electrodes BioSemi	None	ECGi determines activation times of ventricular electric activity

AF, atrial fibrillation; ARVC, arrhythmogenic right ventricular cardiomyopathy; AT, atrial tachycardia; BrS, Brugada syndrome; CHD, congenital heart disease; CHF, congestive heart failure; CRT, cardiac resynchronization therapy; CT, computed tomography; DTW, dynamic time wrapping; ECG, electrocardiography; ECGi, electrocardiographic imaging; FRA, fastest route algorithm; HF, heart failure; LBBB, left bundle branch block; LQTS, long QT syndrome; MI, myocardial infarction; NEEES, non-invasive epicardial and endocardial electrophysiology system; NICE, non-invasive imaging of cardiac electrophysiology; OTVT, outflow tract ventricular tachycardia; PVC, premature ventricular complexes; RBBB, right bundle branch block; RCT, randomized controlled trial; SBRT, stereotactic body radiation therapy; VF, ventricular fibrillation; VIVO, view into ventricular onset; VT, ventricular tachycardia; WPW, Wolf–Parkinson–White syndrome.