The QT interval is a risk marker for cardiac events such as torsades de pointes. However, QT measurements obtained from a 12-lead ECG during clinic hours may not capture the full extent of a ...patient's daily QT range.
The purpose of this study was to evaluate the utility of 24-hour Holter ECG recording in patients with long QT syndrome (LQTS) to identify dynamic changes in the heart rate-corrected QT interval and to investigate methods of visualizing the resulting datasets.
Beat-to-beat QTc (Bazett) intervals were automatically measured across 24-hour Holter recordings from 202 LQTS type 1, 89 type 2, and 14 type 3 genotyped patients and a reference group of 200 healthy individuals. We measured the percentage of beats with QTc greater than the gender-specific threshold (QTc ≥470 ms in women and QTc ≥450 ms in men). The percentage of beats with QTc prolongation was determined across the 24-hour recordings.
Based on the median percentage of heartbeats per patient with QTc prolongation, LQTS type 1 patients showed more frequent QTc prolongation during the day (~3 PM) than they did at night (~3 AM): 97% vs 48%, P ~10(-4) for men, and 68% vs 30%, P ~10(-5) for women. LQTS type 2 patients showed less frequent QTc prolongation during the day compared to nighttime: 87% vs 100%, P ~10(-4) for men, and 62% vs 100%, P ~10(-3) for women.
In patients with genotype-positive LQTS, significant differences exist in the degree of daytime and nocturnal QTc prolongation. Holter monitoring using the "QT clock" concept may provide an easy, fast, and accurate method for assessing the true personalized burden of QTc prolongation.
Early self-detection of atrial fibrillation (AF) can help delay and/or prevent significant associated complications, including embolic stroke and heart failure. We developed a facial video ...technology, videoplethysmography (VPG), to detect AF based on the analysis of facial pulsatile signals.
The purpose of this study was to evaluate the accuracy of a video-based technology to detect AF on a smartphone and to test the performance of the technology in AF patients across the whole spectrum of skin complexion and under various recording conditions.
The performance of video-based monitoring depends on a set of factors such as the angle and the distance between the camera and the patient’s face, the strength of illumination, and the patient’s skin tone. We conducted a clinical study involving 60 subjects with a confirmed diagnosis of AF. A continuous electrocardiogram was used as the gold standard for cardiac rhythm annotation. The VPG technology was fine-tuned on a smartphone for the first 15 subjects. Validation recordings were then done using 7053 measurements collected from the remaining 45 subjects.
The VPG technology detected the presence of AF using the video camera from a common smartphone with sensitivity and specificity ≥90%. The ambient level of illumination needs to be ≥100 lux for the technology to deliver consistent performance across all skin tones.
We demonstrated that facial video-based detection of AF provides accurate outpatient cardiac monitoring including high pulse rate accuracy and medical-grade performance for AF detection.
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Background
The risk of ventricular arrhythmias in patients on QT prolonging drugs is indicated to be increased early after cardioversion (CV) of atrial fibrillation (AF) to sinus rhythm (SR). ...Sotalol, used to prevent AF relapse, prolongs cardiac repolarization and corrected QT interval (QTc). A pronounced QTc prolongation is an established marker of pro‐arrhythmias. Our objective was to use novel technique to quantify and evaluate the diurnal variation of the QTc interval after elective CV to SR in patients on sotalol or metoprolol.
Methods
Fifty patients underwent twelve‐lead Holter recording for 24 hr after elective CV for persistent AF. All patients had the highest tolerable stable dose of sotalol (n = 27) or metoprolol (n = 23). Measurements of QT and RR intervals were performed on all valid beats.
Results
A clear diurnal variation of both HR and QTc was seen in both groups, more pronounced in patients on sotalol, where a high percentage of heartbeats with QTc >500 ms was observed, especially at night. Six patients (22%) on sotalol but none on metoprolol had >20% of all heart beats within the 24‐hour recording with QTc >500 ms.
Conclusion
Twenty‐four‐hour Holter recordings with QT‐measurement immediately after CV demonstrated that one in five patients on sotalol had >20% of all heart beats with prolonged QTc >500 ms, especially during night‐time. The QTc diurnal variation was retained in patients on β‐blockade or a potent class III anti‐arrhythmic drug with β‐blocking properties.
Background:
Environmental contamination is a major risk factor for multidrug-resistant organism (MDRO) exposure and transmission in the healthcare setting. Sponge-stick sampling methods have been ...developed and validated for MDRO epidemiological investigations, leading to their recommendation by public health agencies. However, similar bacteriological yields with more readily available methods that require less processing time or specialized equipment have also been reported. We compared the ability of 4 sampling methods to recover a variety of MDRO taxa from a simulated contaminated surface.
Methods:
We assessed the ability of (1) cotton swabs moistened with phosphate buffer solution (PBS), (2) e-swabs moistened with e-swab solution, (3) cellulose-containing sponge sticks (CSS), and (4) non–cellulose-containing sponge sticks (NCS) to recover extended-spectrum β-lactamase (ESBL)–producing
Escherichia coli
, carbapenem-resistant
Pseudomonas aeruginosa
(CRPA), carbapenem-resistant
Acinetobacter baumannii
(CRAB), methicillin-resistant
Staphylococcus aureus
(MRSA), vancomycin-resistant
Enterococcus faecium
(VRE), and a mixture that contained VRE, MRSA, and ESBL organisms. A solution of known bacterial inoculum (~10
5
CFU/mL) was made for each MDRO. Then, 1 mL solution was pipetted on a stainless-steel surface (8 × 12 inch) in 5 µL dots and allowed to dry for 1 hour. All samples were collected by 1 individual to minimize variation in technique. Sponge sticks were expressed in PBS containing 0.02% Tween 80 using a stomacher, were centrifuged, and were then resuspended in PBS. Cotton and e-swabs were spun in a vortexer. Then, 1 mL of fluid from each method was plated to selective and nonselective media in duplicate and incubated at 35°C for 24 hours (MRSA plates, 48 hours) (Fig. 1). CFU per square inch and percentage recovery were calculated.
Results:
Table 1 shows the CFU per square inch and percentage recovery for each sampling method–MDRO taxa combination. The percentage recovery varied across MDRO taxa. Across all methods, the lowest rate of recovery was for CRPA and the highest was for VRE. Regardless of MDRO taxa, the percentage recovery was highest for the sponge stick (CSS and NCS) compared to swab (cotton and E-swab) methods across all taxa (Table 1 and Fig. 2).
Conclusions:
These findings support the preferential use of sponge sticks for the recovery of MDROs from the healthcare environment, despite the additional processing and equipment time needed for sponge sticks. Further studies are needed to assess the robustness of these findings in noncontrived specimens as well as the comparative effectiveness of different sampling methods for non–culture-based MDRO detection.
Disclosure:
None
The oxygen isotope composition of well-preserved trilobite eye calcite, retaining its original optical properties, represents a possible source of information on Paleozoic sea temperatures. Species ...of the epipelagic telephinid genera Carolinites and Opipeuterella from strata of Early to Middle Ordovician age in Spitsbergen and Australia were analyzed, and compared with benthic asaphid species. Scanning electron microscope (SEM), cathodoluminescence (CL), electron microprobe and Electron Backscatter Diffraction (EBSD) techniques were used to assess eye preservation prior to isotope analysis. Some apparently well-preserved eyes are identified from the Valhallfonna (Spitsbergen) and Emanuel (Australia) formations. The eyes show a wide variation in δ18O values: −6.2‰ to −9.8‰ for the Valhallfonna Formation, −3.2‰ to −10.4‰ for the Emanuel Formation, and −3.6‰ to −7.4‰ for the Horn Valley Siltstone (Australia). Intra-eye Secondary Ion Mass Spectrometry (SIMS) isotope results reveal an even larger range in δ18O in some specimens (δ18O of −2.4‰ to −10.4‰), suggesting that the trilobite eyes have undergone cryptic recrystallization. A sub-set of trilobite cuticle from the three formations were analyzed for their carbonate clumped isotope compositions (Δ47), and yielded crystallization temperatures above 50°C, consistent with diagenetic alteration. The SIMS and Δ47 results suggest that classic preservation assessment protocols for the stable isotope study of deep-time carbonate samples may be insufficient, especially for these techniques. There is a need for extensive microstructural characterization of lower Paleozoic biogenic carbonates, by techniques including EBSD, SIMS and Δ47, before their stable isotope signatures can be used with certainty in paleoclimate studies.
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•Preservation assessment shows some well-preserved Ordovician trilobite eyes.•Ordovician trilobite eyes yield δ18O values similar to Ordovician brachiopods.•SIMS and clumped isotope results indicate diagenetic alteration of trilobites.•Classic protocols to assess preservation may be inapt for most ancient carbonates.
One of the promising opportunities of digital health is its potential to lead to more holistic understandings of diseases by interacting with the daily life of patients and through the collection of ...large amounts of real-world data. Validating and benchmarking indicators of disease severity in the home setting is difficult, however, given the large number of confounders present in the real world and the challenges in collecting ground truth data in the home. Here we leverage two datasets collected from patients with Parkinson's disease, which couples continuous wrist-worn accelerometer data with frequent symptom reports in the home setting, to develop digital biomarkers of symptom severity. Using these data, we performed a public benchmarking challenge in which participants were asked to build measures of severity across 3 symptoms (on/off medication, dyskinesia, and tremor). 42 teams participated and performance was improved over baseline models for each subchallenge. Additional ensemble modeling across submissions further improved performance, and the top models validated in a subset of patients whose symptoms were observed and rated by trained clinicians.
The collection of long-term health data is accelerating with the advent of portable/wearable medical devices including electrocardiograms (ECGs). This large corpus of data presents great ...opportunities to improve the quality of cardiac care. However, analyzing the data from these sensors is a challenge; the relevant information from ~120 000 heart beats per patient per day must be condensed into a human-readable form. Our goal is to facilitate the analysis of these unwieldy data sets. We have developed an open source tool for creating easy-to-interpret plots of cardiac information over long periods. We call these plots ECG clocks. The utility of our ECG clock library is demonstrated through multiple examples drawn from a database of 24-h Holter recordings. In these case studies, we focus on the visualization of heart rate and QT dynamics. The ECG clock concept is shown to be relevant for both physicians and researchers, for identifying healthy and abnormal values and patterns in ECG recordings. In this paper, we describe how to use the ECG clock library to analyze 24-h ECG recordings, and how to extend the source code for your own purposes. The tool is applicable to a wide range of cardiac monitoring tasks, such as heart rate variability or ST elevation. This library, which we have made freely available, can help provide new insights into circadian patterns of cardiac function in individuals and groups.
This collaborative statement from the International Society for Holter and Noninvasive Electrocardiology/ Heart Rhythm Society/ European Heart Rhythm Association/ Asia Pacific Heart Rhythm Society ...describes the current status of mobile health ("mHealth") technologies in arrhythmia management. The range of digital medical tools and heart rhythm disorders that they may be applied to and clinical decisions that may be enabled are discussed. The facilitation of comorbidity and lifestyle management (increasingly recognized to play a role in heart rhythm disorders) and patient self‐management are novel aspects of mHealth. The promises of predictive analytics but also operational challenges in embedding mHealth into routine clinical care are explored.
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