Can smartphone wireless ECGs be used to accurately assess ECG intervals in pediatrics? A comparison of mobile health monitoring to standard 12-lead ECG

BACKGROUND:Arrhythmias in children are often paroxysmal, complicating the ability to capture the abnormal rhythm on routine ECG during an outpatient visit. The Alivecor Kardia Mobile (KM) device is a wireless mobile health (mHealth) device that generates a single lead ECG tracing with a FDA-approved algorithm for detection of atrial fibrillation in adults. OBJECTIVE:The goal of this study is to assess the accuracy of interval measurements on KM tracings by directly comparing to standard 12-lead ECGs in pediatric patients. METHODS:This single center, prospective study enrolled pediatric outpatients, age 20ms with 4/9 (44%) having a conduction disorder and 2/9 (22%) having marked sinus arrhythmia. Bland-Altman method of agreement demonstrated strong agreement for QRSd and QTc. The AF algorithm reported 4/30 (13%) false positive "possible AF" diagnoses (rhythm over-read on KM demonstrated n = 3 marked sinus arrhythmia, n = 1 sinus rhythm with aberrated PACs) resulting in a specificity of 87%. CONCLUSION:The Alivecor Kardia device produces accurate single lead ECG tracings in both healthy children and children with cardiac disease or rhythm abnormalities across the pediatric spectrum. This mHealth application provides an accurate, non-invasive, real-time approach for ambulatory ECG monitoring in children and adolescents

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Force‐sensing catheters during pediatric radiofrequency ablation: The FEDERATION Study

Background Based on data from studies of atrial fibrillation ablations, optimal parameters for the TactiCath (TC; St. Jude Medical, Inc) force‐sensing ablation catheter are a contact force of 20 g and a force‐time integral of 400 g·s for the creation of transmural lesions. We aimed to evaluate TC in pediatric and congenital heart disease patients undergoing ablation. Methods and Results Comprehensive chart and case reviews were performed from June 2015 to March 2016. Of the 102 patients undergoing electrophysiology study plus ablation, 58 (57%) underwent ablation initially with a force‐sensing catheter. Patients had an average age of 14 (2.4–23) years and weight of 58 (18–195) kg with 15 patients having abnormal cardiac anatomy. Electrophysiology diagnoses for the + TC group included 30 accessory pathway–mediated tachycardia, 24 atrioventricular nodal reentrant tachycardia, and 7 other. Baseline generator settings included a power of 20 W, temperature of 40°, and 6 cc/min flow during lesion creation with 11 patients (19%) having alterations to parameters. Seventeen patients (30%) converted to an alternate ablation source. A total of 516 lesions were performed using the TC with a median contact force of 6 g, force‐time integral of 149 g·s, and lesion size index of 3.3. Median‐term follow‐up demonstrated 5 (10%) recurrences with no acute or median‐term complications. Conclusions TactiCath can be effectively employed in the treatment of pediatric patients with congenital heart disease with lower forces than previously described in the atrial fibrillation literature. Patients with atrioventricular nodal reentrant tachycardia or atrioventricular reciprocating tachycardia may not require transmural lesions and the TC may provide surrogate markers for success during slow pathway ablation. </jats:sec

Adherence to Surveillance Guidelines in Nondysplastic Barrett’s Esophagus

Introduction: Surveillance patterns in Barrett's esophagus (BE) are not well characterized. Guidelines published between 2002 and 2008 recommended surveillance esophagogastroduodenoscopy (sEGD) at 3-year intervals for nondysplastic BE (NDBE). We assessed guideline adherence in incident NDBE in a Veterans Affairs (VA)-based study. Methods: At a single VA center, we identified incident cases of biopsy-confirmed NDBE between January, 2006 and December, 2008. We excluded patients aged 76 years and above and those who developed BE-associated dysplasia or cancer during follow-up. All sEGDs through October, 2014 were documented. Our primary criteria classified cases as guideline adherent if a sEGD was performed within 6 months of each expected 3-year surveillance interval; in cases with >=2 sEGDs, 1 sEGD >6 months, and <=1 year outside an interval was allowed if the average interval was between 2.5 and 3.5 years. Comorbidity, primary care encounters, presence of long-segment BE (LSBE), endoscopist recommendations, and Charlson comorbidity index (CCI) were assessed. Results: We identified 110 patients (96.4% male, 93.6% white) with mean age 58.9+/-8.5 years at index EGD. Median follow-up was 6.7 years (range, 3.7 to 8.6). Thirty-three (30.0%) cases were guideline adherent; 77 (70.0%) cases were nonadherent, including 52 (47.3%) with irregular surveillance and 25 (22.7%) with no surveillance. Forty cases (14 adherent) had 1 sEGD, 36 (18 adherent) had 2, 8 (1 adherent) had 3, and 1 nonadherent case had 4. Adherent cases were significantly older (61.5 vs. 57.9 y, P=0.04), and tended to have more LSBE (33.3% vs. 20.8%, P=0.16). There were no differences between adherent and nonadherent cases in annual primary care encounters (72.7% vs. 66.2%, P=0.66), CCI>=4 (15.2% vs. 15.6%, P=0.95), biopsy-positive sEGDs (75.8% vs. 76.6%, P=0.92), and any recommendation for subsequent surveillance (81.8% vs. 77.9%, P=0.65). A logistic regression model using age, CCI, and LSBE showed an independent association between adherence and older age (P=0.03). Conclusions: In a single-center VA cohort, sEGD of NDBE was mostly nonadherent to guidelines. Adherent cases were older at baseline with a trend toward more LSBE. A larger study is needed to identify medical and social factors associated with adherence or nonadherence to surveillance

Three‐dimensional, multifluid, high spatial resolution MHD model studies of the solar wind interaction with Mars

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95318/1/jgra21138.pd

Bringing closure to microlensing mass measurement

Interferometers offer multiple methods for studying microlensing events and determining the properties of the lenses. We investigate the study of microlensing events with optical interferometers, focusing on narrow-angle astrometry, visibility, and closure phase. After introducing the basics of microlensing and interferometry, we derive expressions for the signals in each of these three channels. For various forecasts of the instrumental performance, we discuss which method provides the best means of measuring the lens angular Einstein radius theta_E, a prerequisite for determining the lens mass. If the upcoming generation of large-aperture, AO-corrected long baseline interferometers (e.g. VLTI, Keck, OHANA) perform as well as expected, theta_E may be determined with signal-to-noise greater than 10 for all bright events. We estimate that roughly a dozen events per year will be sufficiciently bright and have long enough durations to allow the measurement of the lens mass and distance from the ground. We also consider the prospects for a VLTI survey of all bright lensing events using a Fisher matrix analysis, and find that even without individual masses, interesting constraints may be placed on the bulge mass function, although large numbers of events would be required.Comment: 23 pages, aastex, submitted to Ap