Feasibility study of a 3D camera to reduce electrode repositioning errors during longitudinal ECG acquisition.

INTRODUCTION: Longitudinal monitoring of sometimes subtle waveform changes of the 12­lead electrocardiogram (ECG) is complicated by patient-specific and technical factors, such as the inaccuracy of electrode repositioning. This feasibility study uses a 3D camera to reduce electrode repositioning errors, reduce ECG waveform variability and enable detailed longitudinal ECG monitoring. METHODS: Per subject, three clinical ECGs were obtained during routine clinical follow-up. Additionally, two ECGs were recorded guided by two 3D cameras, which were used to capture the precordial electrode locations and direct electrode repositioning. ECG waveforms and parameters were quantitatively compared between 3D camera guided ECGs and clinical ECGs. Euclidian distances between original and repositioned precordial electrodes from 3D guided ECGs were measured. RESULTS: Twenty subjects (mean age 65.1 ± 8.2 years, 35% females) were included. The ECG waveform variation between routine ECGs was significantly higher compared to 3D guided ECGs, for both the QRS complex (correlation coefficient = 0.90 vs 0.98, p < 0.001) and the STT segment (correlation coefficient = 0.88 vs. 0.96, p < 0.001). QTc interval variation was reduced for 3D camera guided ECGs compared to routine clinical ECGs (5.6 ms vs. 9.6 ms, p = 0.030). The median distance between 3D guided repositioned electrodes was 10.0 [6.4-15.2] mm, and did differ between males and females (p = 0.076). CONCLUSIONS: 3D guided repositioning of precordial electrodes resulted in, a low repositioning error, higher agreement between waveforms of consecutive ECGs and a reduction of QTc variation. These findings suggest that longitudinal monitoring of disease progression using 12­lead ECG waveforms is feasible in clinical practice.

Clinical Characteristics and Follow-Up of Pediatric-Onset Arrhythmogenic Right Ventricular Cardiomyopathy.

OBJECTIVES: The goal of this study was to describe characteristics, cascade screening results, and predictors of adverse outcome in pediatric-onset arrhythmogenic right ventricular cardiomyopathy (ARVC). BACKGROUND: Although ARVC is increasingly recognized in children, pediatric ARVC cohorts remain underrepresented in the literature. METHODS: This study included 12 probands with pediatric-onset ARVC (aged <18 years at diagnosis) and 68 pediatric relatives (aged <18 years at first evaluation) referred for cascade screening. ARVC diagnosis was based on 2010 Task Force Criteria. Clinical presentation, diagnostic testing, and outcomes (sustained ventricular tachycardia [VT]; heart failure) were ascertained. Predictors of adverse outcome were determined by using univariable logistic regression. RESULTS: Pediatric-onset ARVC was diagnosed in 12 probands and 12 (18%) relatives at a median age of 16.6 years (interquartile range: 13.8-17.4 years), whereas 12 (18%) relatives reached ARVC diagnosis as adults (median age, 22.0 years; interquartile range: 20.0-26.7 years). Sudden cardiac death/arrest was the first disease manifestation in 3 (25%) probands and 3 (4%) relatives. In patients without ARVC diagnosis at presentation (n = 61), electrocardiogram and Holter monitoring abnormalities occurred before development of imaging Task Force Criteria (7.3 ± 5.0 years vs 8.4 ± 5.0 years). Clinical course was characterized by sustained VT (91%) and heart failure (36%) in probands, which were rare in relatives (2% and 0%, respectively). Male sex (P < 0.01), T-wave inversion V1-V3 (P < 0.01), premature ventricular complexes/runs (P ≤ 0.01), and decrease in biventricular ejection fraction (P ≤ 0.01) were associated with VT occurrence. CONCLUSIONS: Pediatric ARVC carries high arrhythmic risk, especially in probands. Disease progression is particularly observed on electrocardiogram or Holter monitoring. Arrhythmic events are associated with male sex, T-wave inversions, premature ventricular complexes/runs, and reduced biventricular ejection fraction.

Comparing Non-invasive Inverse Electrocardiography With Invasive Endocardial and Epicardial Electroanatomical Mapping During Sinus Rhythm.

This study presents a novel non-invasive equivalent dipole layer (EDL) based inverse electrocardiography (iECG) technique which estimates both endocardial and epicardial ventricular activation sequences. We aimed to quantitatively compare our iECG approach with invasive electro-anatomical mapping (EAM) during sinus rhythm with the objective of enabling functional substrate imaging and sudden cardiac death risk stratification in patients with cardiomyopathy. Thirteen patients (77% males, 48 ± 20 years old) referred for endocardial and epicardial EAM underwent 67-electrode body surface potential mapping and CT imaging. The EDL-based iECG approach was improved by mimicking the effects of the His-Purkinje system on ventricular activation. EAM local activation timing (LAT) maps were compared with iECG-LAT maps using absolute differences and Pearson's correlation coefficient, reported as mean ± standard deviation [95% confidence interval]. The correlation coefficient between iECG-LAT maps and EAM was 0.54 ± 0.19 [0.49-0.59] for epicardial activation, 0.50 ± 0.27 [0.41-0.58] for right ventricular endocardial activation and 0.44 ± 0.29 [0.32-0.56] for left ventricular endocardial activation. The absolute difference in timing between iECG maps and EAM was 17.4 ± 7.2 ms for epicardial maps, 19.5 ± 7.7 ms for right ventricular endocardial maps, 27.9 ± 8.7 ms for left ventricular endocardial maps. The absolute distance between right ventricular endocardial breakthrough sites was 30 ± 16 mm and 31 ± 17 mm for the left ventricle. The absolute distance for latest epicardial activation was median 12.8 [IQR: 2.9-29.3] mm. This first in-human quantitative comparison of iECG and invasive LAT-maps on both the endocardial and epicardial surface during sinus rhythm showed improved agreement, although with considerable absolute difference and moderate correlation coefficient. Non-invasive iECG requires further refinements to facilitate clinical implementation and risk stratification.