Electrocardiographic Imaging for Cardiac Arrhythmias and Resynchronization Therapy

Helder Pereira; Steven Niederer; Christopher A. Rinaldi

Disclosures

Europace. 2020;22(10):1447-1462. 

In This Article

Arrhythmogenic Syndromes

Electrocardiographic imaging might provide further insights in other arrhythmogenic syndromes. In a study of 25 patients with BrS, Zhang et al.[40] showed that the abnormal electrophysiological substrate was localized in the right ventricular outflow tract that displays delayed activation, prolonged repolarization, and steep repolarization gradients. Six patients with right bundle branch block (RBBB) and seven other healthy individuals served as comparison and control groups, in which the characteristics seen in BrS were absent. By revealing the differences in epicardial activation, repolarization, and electrogram morphologies, ECGi might help to differentiate BrS from RBBB.

A different study used ECGi to map the cardiac electrophysiological substrate in 25 patients with genetically and phenotypically established long QT syndrome (LQTS). With some variations between and within genotypic groups, one of the characteristics of the electrophysiological substrate in LQTS appeared to be the regions of steep spatial dispersion of repolarization in the ventricular epicardium as well as a long activation–recovery interval. These findings further supported the previous theory of re-entry as a main mechanism in LQTS. The authors concluded that ECGi might play a potential role in risk stratification in patients with this disorder.[43]

Electrocardiographic imaging can be of clinical significance in WPW syndrome. In 14 children diagnosed with WPW syndrome without other cardiac abnormalities, ECGi mapping correctly localized and evaluated the ventricular insertion sites of accessory pathways for further ablation guidance.[49] Berger et al.[55] also reported the accurate detection of accessory pathway insertion sites in a study of seven adult patients with WPW syndrome using ECGi.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a clinical disorder characterized by RV dilation, RV dysfunction, and regional RV wall motion abnormalities. Impairment in desmosome function leads to myocardial injury that causes fibrofatty infiltration in the RV and some parts of the left ventricle. Patients with ARVC are at significant risk of developing VT and sudden cardiac death. Andrews et al.[46] suggested that ECGi may provide a better understanding of the disease substrate and improve patient care. In their study, the investigators evaluated 20 patients with ARVC and 20 healthy individuals. The authors found longer ventricular activation duration and prolonged mean epicardial activation-recovery intervals, all of which co-localized with pathological anatomical scar detected by cardiac MRI.

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