A Novel Wearable Device for Continuous Ambulatory ECG Recording: Proof of Concept and Assessment of Signal Quality.

Diagnosis of arrhythmic disorders is challenging because of their short-lasting, intermittent character. Conventional technologies of noninvasive ambulatory rhythm monitoring are limited by modest sensitivity. We present a novel form of wearable electrocardiogram (ECG) sensors providing an alternative tool for long-term rhythm monitoring with the potential of increased sensitivity to detect intermittent or subclinical arrhythmia. The objective was to assess the signal quality and R-R coverage of a wearable ECG sensor system compared to a standard 3-lead Holter. In this phase-1 trial, healthy individuals underwent 24-h simultaneous rhythm monitoring using the OMsignal system together with a 3-lead Holter recording. The OMsignal system consists of a garment (bra or shirt) with integrated sensors recording a single-lead ECG and an acquisition module for data storage and processing. Head-to-head signal quality was assessed regarding adequate P-QRS-T distinction and was performed by three electrophysiologists blinded to the recording technology. The accuracy of signal coverage was assessed using Bland-Altman analysis. Fifteen individuals underwent simultaneous 24-h recording. Signal quality and accuracy of the OMgaments was equivalent to Holter-monitoring (84% vs 93% electrophysiologists rating, p = 0.06). Signal coverage of R-R intervals showed a very close overlay between the OMsignal system and Holter signals, mean difference in heart rate of 2 5 bpm. The noise level of OMgarments was comparable to Holter recording. OMgarments provide high signal quality for adequate rhythm analysis, representing a promising novel technology for long-term non-invasive ECG monitoring.

Cardiac Implantable Electronic Device Infection: Detailed Analysis of Cost Implications.

BACKGROUND: Infections of cardiac implantable electronic devices (CIED) are associated with significant morbidity and mortality. Despite many preventive measures, this condition is associated with significant costs for the health care system. METHODS: We retrospectively analyzed all infection cases referred for lead extraction at a single university hospital over 1 year (2015-2016). We then calculated all costs related to the infection episode per patient using hospital databases and charts review. RESULTS: Thirty-eight patients with CIED infections (29% women-mean age 71 ± 14 years) were referred for lead extraction (27 pocket infections, 11 endocarditis). Devices were mainly pacemakers (60%). When the pathogen was identified, Staphylococcus aureus methicillin sensitive was the main cause. Extraction was performed in all but 3 cases (92%). One death occurred in the nonextracted group. Respective durations of hospitalization and intravenous and antibiotic administration for patients undergoing extraction were 21 and 36 days. The calculated mean total cost for CIED infection management was CAD$29,907 (median: 26,879; range: CAD$4,827-$62,585). Mean hospital charges were CAD$12,291, accounting for 41% of the total costs. CONCLUSIONS: This study represents the first analysis of the direct costs associated with lead extraction in Canada. Device infections are associated with significant costs and increased morbidity. Any preventive measure will have a significant impact on the economic burden of the health care system and patient outcome after lead extraction.

Spatial Relationships of Complex Fractionated Atrial Electrograms and Continuous Electrical Activity to Focal Electrical Sources: Implications for Substrate Ablation in Human Atrial Fibrillation.

OBJECTIVES: This study sought to evaluate the spatial relationships of focal electrical sources (FSs) to complex fractionated atrial electrograms (CFAE) and continuous electrical activity (CEA). BACKGROUND: Fractionated atrial electrograms have been associated with atrial fibrillation (AF) drivers in computational studies and represent ablation targets in the management of persistent AF. METHODS: We included a subset of 66 patients (age: 63 [56, 67] years, 69% persistent AF) with electroanatomic data from the SELECT AF (Selective complex fractionated atrial electrograms targeting for atrial fibrillation) randomized control trial that compared the efficacy of CFAE with CEA ablation in AF patients undergoing pulmonary vein antral ablation. Focal sources were identified based on bipolar electrogram periodicity and QS unipolar electrogram morphology. RESULTS: A total of 77 FSs (median: 1 [1st quartile, 3rd quartile: 1, 2] per patient) were identified most commonly in the pulmonary vein antrum and left atrial appendage. The proportions of FSs inside CFAE and CEA regions were similar (13% vs. 1.3%, respectively; p = 0.13). Focal sources were more likely to be on the border zone of CFAEs than in CEAs (49% vs. 7.8%, respectively; p = 0.012). Following ablation, 53% of patients had ≥1 unablated extrapulmonary vein FS. The median number of unablated FS was higher in patients with AF recurrence post ablation than in patients without (median: 1 [0, 1] vs. 0 [0, 1], respectively; p = 0.026). CONCLUSIONS: One-half of the FSs detected during AF localized to the border of CFAE areas, whereas most of the FSs were found outside CEA areas. CFAE or CEA ablation leaves a number of FS unablated, which is associated with AF recurrence. These findings suggest that many CFAEs may arise from passive wave propagation, remote from FS, which may limit their therapeutic efficacy in AF substrate modification.

Systematic assessment of patients with unexplained cardiac arrest: Cardiac Arrest Survivors With Preserved Ejection Fraction Registry (CASPER).

BACKGROUND: Cardiac arrest without evident cardiac disease may be caused by subclinical genetic conditions. Provocative testing to unmask a phenotype is often necessary to detect primary electrical disease, direct genetic testing, and perform family screening. METHODS AND RESULTS: Patients with apparently unexplained cardiac arrest and no evident cardiac disease (normal cardiac function on echocardiogram, no evidence of coronary artery disease, and a normal ECG) underwent systematic evaluation that included cardiac magnetic resonance imaging, signal-averaged ECG, exercise testing, drug challenge, and selective electrophysiological testing. Diagnostic criteria were based on accepted criteria or provocation of the characteristic clinical features for long-QT syndrome, catecholaminergic polymorphic ventricular tachycardia, Brugada syndrome, early repolarization, arrhythmogenic right ventricular cardiomyopathy, coronary spasm, and myocarditis. Sixty-three patients in 9 centers were enrolled (age 43.0+/-13.4 years, 29 women). A diagnosis was obtained in 35 patients (56%): Long-QT syndrome in 8, catecholaminergic polymorphic ventricular tachycardia in 8, arrhythmogenic right ventricular cardiomyopathy in 6, early repolarization in 5, coronary spasm in 4, Brugada syndrome in 3, and myocarditis in 1. Targeted genetic testing demonstrated evidence of causative mutations in 9 (47%) of 19 patients. Screening of 64 family members of these patients identified 15 affected individuals who were treated (24%). The remaining 28 patients (44%) were considered to have idiopathic ventricular fibrillation. CONCLUSIONS: Systematic clinical testing, including drug provocation and advanced imaging, results in unmasking of the cause of apparently unexplained cardiac arrest in >50% of patients. This approach assists in directing genetic testing to diagnose genetically mediated arrhythmia syndromes, which results in successful family screening.