Measurements of pulse rate using facial video cameras from smart devices in patients diagnosed with atrial fibrillation.

Clinical applications of passive long-term heart rate (HR) monitoring in patients with cardiac arrhythmias include adequate drug titration of atrioventricular (AV) nodal drugs and assessment of medical compliance with treatment. A majority of patients treated with beta-blockers, especially patients with atrial fibrillation (AF), require some degree of drug titration during the first 6 months of treatment to ensure that adequate HR control and medicine compliance has been achieved. Failing to achieve adequate rate control in patients with AF can lead to worsening symptoms, heart failure exacerbations, and potentially tachycardia-induced cardiomyopathy. Enabling video-based monitoring during telehealth patient visits could facilitate providers to measure heart rate (HR) without the need for a dedicated home device (smartwatch, SPO2 device, or others). Videoplethysmography (VPG) is a monitoring technology that measures pulse rate by utilizing front-facing cameras embedded in smart devices. VPG provides a remote and contactless cardiac monitoring solution. We conducted a clinical experiment to evaluate the accuracy of VPG in measuring HR while running on two portable devices: Samsung S10 smartphones and S3 tablets. We used a single­lead ECG to measure the heart rate at the time of the VPG recordings in AF patients. We employed the Bland-Altman method to measure the level of agreement between videoplethysmography and ECG-based measurements of HR. The findings reveal that the mean difference in videoplethysmography and ECG-based heart rate was inferior to 1 bpm across the 2 devices with confidence intervals ranging from 3 to 12 BPM. Our facial video-based HR monitoring solution could assist providers in measuring heart rates in their patients with AF during remote telehealth visits.

The multiple arrhythmia dataset evaluation database (M.A.D.A.E.).

The convergence between wearable and medical device technologies is a natural progression. Miniaturization has allowed the design of small, compact monitoring systems that can record physiological signals over longer periods of time. Thus, the potential for these devices to expand the understanding of disease progression and patients' clinical status is very high. The accuracy of these devices, however, is dependent upon the computer algorithms utilized in the analysis of the large volume of physiological data monitored and/or recorded by the devices. Automated interpretation of the data by these new technologies, therefore, necessitates closer examination by regulatory organizations. The current requirements for the validation of novel Ambulatory ECG (A-ECG) annotation algorithms are based on the AAMI/ANSI-EC57 and IEC60601-2-47 Standard. These standards are being updated, but they rely on a very limited set of digitized ECG recordings from a couple of ECG databases built in the first half of the 70's. These reference signals are obsolete. We are developing a validation tool for computerized methods designed to detect and monitor cardiac activities based on body-surface ECGs. We will rely on a set of existing digital high-resolution 12­lead A-ECG recordings acquired in cardiac patients and healthy individuals. These ECG signals include a large and unique set of electrocardiographic events. This tool is being qualified by the Center for Devices and Radiological Health of the United States Food and Drug Administration (FDA) as a Medical Device Development Tool (MDDT). This document provides insights into the design of the M.A.D.A.E. database, its functionalities, and its ultimate role in enabling the next generations of automatic interpretation of ECG signals.

Semi-automated QRS score as a predictor of survival in CRT treated patients with strict left bundle branch block.

BACKGROUND: Cardiac Resynchronization Therapy (CRT) is widely used for treating selected heart failure patients, but patients with myocardial scar respond worse to treatment. The Selvester QRS scoring system estimates myocardial scar burden using 12-lead ECG. This study's objective was to investigate the scores correlation to mortality in a CRT population. METHODS AND RESULTS: Data on consecutive CRT patients was collected. 401 patients with LBBB and available ECG data were included in the study. QuAReSS software was used to perform Selvester scoring. Mean Selvester score was 6.4, corresponding to 19% scar burden. The endpoint was death or heart transplant; outcome was analyzed using Cox proportional hazards models. A Selvester score >8 was significantly associated with higher risk of the combined endpoint (HR 1.59, p=.014, CI 1.09-2.3). CONCLUSION: Higher Selvester scores correlate to mortality in CRT patients with strict LBBB and might be of value in prognosticating survival.

T-wave morphology can distinguish healthy controls from LQTS patients.

Long QT syndrome (LQTS) is an inherited disorder associated with prolongation of the QT/QTc interval on the surface electrocardiogram (ECG) and a markedly increased risk of sudden cardiac death due to cardiac arrhythmias. Up to 25% of genotype-positive LQTS patients have QT/QTc intervals in the normal range. These patients are, however, still at increased risk of life-threatening events compared to their genotype-negative siblings. Previous studies have shown that analysis of T-wave morphology may enhance discrimination between control and LQTS patients. In this study we tested the hypothesis that automated analysis of T-wave morphology from Holter ECG recordings could distinguish between control and LQTS patients with QTc values in the range 400-450 ms. Holter ECGs were obtained from the Telemetric and Holter ECG Warehouse (THEW) database. Frequency binned averaged ECG waveforms were obtained and extracted T-waves were fitted with a combination of 3 sigmoid functions (upslope, downslope and switch) or two 9th order polynomial functions (upslope and downslope). Neural network classifiers, based on parameters obtained from the sigmoid or polynomial fits to the 1 Hz and 1.3 Hz ECG waveforms, were able to achieve up to 92% discrimination between control and LQTS patients and 88% discrimination between LQTS1 and LQTS2 patients. When we analysed a subgroup of subjects with normal QT intervals (400-450 ms, 67 controls and 61 LQTS), T-wave morphology based parameters enabled 90% discrimination between control and LQTS patients, compared to only 71% when the groups were classified based on QTc alone. In summary, our Holter ECG analysis algorithms demonstrate the feasibility of using automated analysis of T-wave morphology to distinguish LQTS patients, even those with normal QTc, from healthy controls.

The use of beat-to-beat electrocardiogram analysis to distinguish QT/QTc interval changes caused by moxifloxacin from those caused by vardenafil.

QT correction factors (QTc) can cause errors in the interpretation of drug effects on cardiac repolarization because they do not adequately differentiate changes when heart rate or autonomic state deviates from the baseline QT/RR interval relationship. The purpose of our study was to determine whether the new method of QT interval dynamic beat-to-beat (QTbtb) analysis could better discriminate between impaired repolarization caused by moxifloxacin and normal autonomic changes induced by subtle reflex tachycardia after vardenafil. Moxifloxacin produced maximum mean increases of 13-14 ms in QTbtb, QTcF, and QTcI after 4 h. After vardenafil administration, a 10-ms effect could be excluded at all time points with QTbtb but not with QTcF or QTcI. Subset analysis of the vardenafil upper pharmacokinetic quartile showed that the upper bound of QTcF and QTcI was >10 ms, whereas that of QTbtb was <8 ms. This study demonstrated that newer methods of electrocardiogram (ECG) analysis can differentiate changes in the QT interval to improve identification of proarrhythmia risk.

Analysis of T-wave Amplitude Adaptation to Heart Rate Using RR-binning of Long-Term ECG Recordings.

The prognosis of patients with coronary artery disease at the early stage of the disease is a challenge of modern cardiology. There is an urgent need to risk stratify these patients. Holter technology is a cheap and cost effective tool to evaluate electrical abnormalities in the heart. We propose to investigate T-amplitude adaptation to heart rate (HR) using RR-binning. We used daytime recordings from healthy subjects and subjects with acute myocardial infarction (AMI) from the Telemetric and Holter ECG Warehouse. The AMI subjects were divided into two groups based on location of their infarction (group A: anterior or anterior lateral, group B: inferior or inferior lateral). Both AMI groups had acute and stable phase recordings. Population-based T-adaptation to HR was observed for healthy subjects (R2 = 0.92) but was less pronounced for AMI subjects: [Formula: see text].

A Comparison of IIR and Wavelet Filtering for Noise Reduction of the ECG.

This study compares the ability to preserve information and reduce noise contaminants on the ECG for five wavelet filters and three IIR filters. Two 3-lead Holter ECGs were used. White Gaussian Noise was added to the first ECG in increments of 10% coverage. The second ECG contained alternating muscle transients and noise-free segments. Computation times and SNR improvements for different noise coverages were calculated and compared. RMS errors were calculated from noise-free segments on the ECG with transient muscle noise. Wavelet filters improved SNR more than IIR filters when the signal coverage was more than 50% noise. In contrast, the computation times were shorter for IIR filters (6 s) than for wavelet filters (88 s). On the ECG with transient muscle noise there was a trade-off in performance between wavelet and IIR filtering. In a clinical setting where the amount of noise is unknown, using IIR filters appears to be preferred for consistent performance.

A Wavelet-Based Algorithm for Delineation and Classification of Wave Patterns in Continuous Holter ECG Recordings.

Quantitative analysis of the electrocardiogram (ECG) requires delineation and classification of the individual ECG wave patterns. We propose a wavelet-based waveform classifier that uses the fiducial points identified by a delineation algorithm. For validation of the algorithm, manually annotated ECG records from the QT database (Physionet) were used. ECG waveform classification accuracies were: 85.6% (P-wave), 89.7% (QRS complex), 92.8% (T-wave) and 76.9% (U-wave). The proposed classification method shows that it is possible to classify waveforms based on the points obtained during delineation. This approach can be used to automatically classify wave patterns in long-term ECG recordings such as 24-hour Holter recordings.

Leukocytes and the kidney contribute to interstitial inflammation in lupus nephritis.

Interstitial leucocyte infiltration, a prominent feature of lupus nephritis, predicts deterioration of renal function. We used two models of lupus nephritis in mice, one with chronic spontaneous disease and the other with acute interferon-alpha (IFN alpha)-mediated disease. The latter is characterized by the virtual absence of interstitial infiltration. In vivo migration assays showed that splenic leukocytes from spontaneously nephritic mice tended to migrate into non-inflamed syngeneic kidneys. This was enhanced if the recipient kidneys were already inflamed. Kidneys from both chronically and acutely nephritic mice showed similar ability to recruit splenic leukocytes from chronically diseased mice. Leukocytes from acutely diseased mice, however, failed to migrate into chronically inflamed kidney. Compared with those with chronic nephritis, the kidneys of acute nephritic mice expressed less of the inflammatory chemokine CXCL13/BLC. Moreover, leukocytes from acute nephritic mice displayed impaired migration, in vitro, to T-cell chemokine attractants. This study links leukocyte infiltration to both kidney chemokine expression, and leukocyte chemotaxis to kidney-expressed chemokines.

Silage chop length and hay supplementation on milk yield, chewing activity, and ruminal digestion by dairy cows.

The effects of whole-plant corn silage (CS) particle size and long unprocessed grass hay (LH) supplementation on milk yield, chewing activity, and ruminal digestion in dairy cows were evaluated in 2 experiments. In Experiment 1, corn silage harvested at fine (6 mm; FCS) or coarse (23 mm; CCS) theoretical cut length were fed to 22 lactating Holstein cows. Treatments were 2 total mixed rations containing 58% of dry matter (DM) as FCS or CCS. Diet DM intake tended to be higher in cows fed FCS than those fed CCS (23.4 vs. 22.1 kg/d). However, milk yield and composition, body condition score, and plasma metabolite concentrations were not affected by the dietary treatments. In the second experiment, 5 cannulated Holstein cows were used in a 5 x 5 Latin square design to evaluate the effects of the addition of LH to the diets evaluated in Experiment 1 on chewing activity and ruminal digestion. Treatments were 5 total mixed rations: FCS-based diet plus the addition of 0, 5, or 10% LH (DM basis) and CCS-based diet plus 0 or 5% LH. Long hay addition linearly decreased DM intake in cows fed FCS-based diets (25.0 to 21.7 kg/d), but increased DM intake in those fed CCS-based diets (22.7 to 27.1 kg/d). The intake of neutral detergent fiber (NDF) increased with LH addition in CCS-based diets (7.6 vs. 9.4 kg/d). Rumination time increased (16.8 to 21.0 min/kg of DM intake) when LH was added to FCS-based diets, but it decreased when included in CCS-based diets (18.8 vs. 12.9 min/kg of DM intake). Ruminal pH was higher (5.9 vs. 5.7) and lag-time for in situ NDF disappearance was shorter (3.5 vs. 8.7 h) for cows fed CCS compared with cows fed FCS. The rate of NDF disappearance tended to be higher for the CCS-based diet with 5% LH than for the diet with 0% LH (2.0 vs. 4.4 %/h), but solids passage rate was not affected by the treatments. These results suggest that addition of LH to FCS-based diets does not affect ruminal environment or digestion, but depressed DM intake. In contrast, addition of LH to CCS-based diets may improve ruminal NDF digestion, increasing DM intake by reducing filling effect and time needed for rumination.

Electrocardiographic method for identifying drug-induced repolarization abnormalities associated with a reduction of the rapidly activating delayed rectifier potassium current.

Several important non-cardiac drugs have been removed from the market after revealing harmful effect that was not identified during prior safety-assessment studies. We developed a new technique for the measurements of repolarization abnormalities from surface ECGs; this method improves sensitivity and specificity of the current technique used to identify the presence of abnormal ion current kinetics in the myocardial cells namely a prolongation of the QT interval on the surface ECG signal. We described in this paper the method and preliminary results, revealing the superiority of our technique that may play a role in the future of drug-safety assessment.

[Chest diseases in elderly: role of imaging and clinical features]. / Pathologie pulmonaire du sujet âgé: rôle de l'imagerie et aspects cliniques.

Chest x-ray is the most useful examination in the elderly as community acquired pneumonia is very frequent in this high risk population. Technical details have to be considered due to the clinical status of elderly patients. Raising arms above the head may help in the radiographic diagnosis of pneumonia. Guidelines for good radiological practice indicate that a chest x-ray should be done in patients with acute respiratory illness and dementia. Clinical and biological findings of pneumonia may be misleading in the elderly and treatment should be instituted rapidly to avoid complications. Lung cancer of elderly patients has to be investigated and treated without consideration for age. Surgery should be done whenever the tumor is removable by lobectomy. Chemotherapy may be safe even in patients older than 80 with an acceptable quality of life.

Heart rate variability in patients with congenital long QT syndrome.

BACKGROUND: The congenital long QT syndrome (LQTS) affecting myocardial repolarization is caused by mutations in different cardiac potassium or sodium channel genes. Adrenergic triggers are known to initiate life-threatening torsade de pointes ventricular tachycardias in LQTS patients, and anti-adrenergic therapy has been shown to be effective in many cases. Despite this well-documented adrenergic component, the data about autonomic modulation of the heart rate in LQTS, as described by heart rate variability (HRV) analysis, are very limited. METHODS: Conventional time- and frequency-domain and newer nonlinear measures of HRV were compared in resting conditions among 27 LQTS patients with gene mutations at the LQT1 (n = 8), LQT2 (n = 10) or LQT3 (n = 9) loci and 34 LQTS noncarrier family members. RESULTS: None of the conventional time- or frequency-domain or newer nonlinear measures of HRV differed significantly between the LQTS carriers and LQTS noncarriers or between the LQT1, LQT2, and LQT3 carriers. CONCLUSIONS: These findings suggest that baseline cardiac autonomic modulation of the heart rate measured in resting conditions by traditional or newer nonlinear measures of HRV is not altered in LQTS patients. Furthermore, no differences are observed in HRV parameters between LQTS patients with potassium (KvLQT1, HERG), and sodium (SCN5A) ion channel gene mutations. HRV analysis in resting conditions does not improve phenotypic characterization of LQTS patients.

The BTB/POZ domain of the regulatory proteins Bric à brac 1 (BAB1) and Bric à brac 2 (BAB2) interacts with the novel Drosophila TAF(II) factor BIP2/dTAF(II)155.

The BTB/POZ domain is an evolutionarily conserved protein-protein interaction domain present in the N-terminal region of numerous transcription factors involved in development, chromatin remodeling, and human cancers. This domain is involved in homomeric and heteromeric associations with other BTB/POZ domains. The Drosophila BTB/POZ proteins Bric à brac 1 (BAB1) and Bric à brac 2 (BAB2) are developmentally regulated transcription factors which are involved in pattern formation along the proximo-distal axis of the leg and antenna, in the morphogenesis of the adult ovaries, and in the control of sexually dimorphic characters. We have identified partners of the BAB1 protein by using the two-hybrid system. The characterization of one of these proteins, called BIP2 for BAB Interacting Protein 2, is presented. BIP2 is a novel Drosophila TATA-box Protein Associated Factor (TAF(II)), also named dTAF(II)155. We show that the BTB/POZ domains of BAB1 and BAB2 are sufficient to mediate a direct interaction with BIP2/dTAF(II)155. This provides a direct link between these BTB/POZ transcription factors and the basal transcriptional machinery. We discuss the implications of the interaction between a BTB/POZ domain and a TAF(II) for the molecular mechanisms of transcriptional control mediated by BTB/POZ transcription factors.

Cardiovascular effects of air pollution: what to measure in ECG?

Epidemiologic evidence indicates that air pollution adversely affects the cardiovascular system, leading to increased cardiovascular morbidity and mortality. However, the mechanisms of such an association are unknown. Although potential mechanisms of deleterious effects of air pollution may involve response of the respiratory system, immunologic response, or coagulation abnormalities, the cardiovascular system seems to be the common end point of these pathways. Cardiovascular response to any stress (which may include air pollution) is a consequence of a complex interplay between the autonomic nervous system governing centrally mediated control of the cardiovascular system, a myocardial substrate (current state of the myocardium) altered in the course of disease processes, and myocardial vulnerability leading to arrhythmogenic or ischemic response. Through the use of standard electrocardiograms (ECGs), exercise ECG testing, and long-term ambulatory ECG monitoring, modern electrocardiology makes a valuable contribution to understanding the different mechanistic factors involved in the increase in adverse cardiovascular events due to air pollution. Heart rate variability analysis can provide quantitative insight into the autonomic response of the cardiovascular system to air pollution. Analysis of ventricular repolarization in an ECG (both duration and morphology) gives valuable information about the status and dynamic behavior of myocardium, reflecting myocardial substrate and vulnerability. ST-segment analysis of ECGs is used routinely to monitor the magnitude of ischemia and could be used to monitor subtle changes in the myocardium in subjects exposed to air pollution. Comprehensive analysis of ECG parameters describing the influence of the autonomic nervous system, the role of myocardial substrate, and the contribution of myocardial vulnerability could and should be employed in air pollution studies, especially as those mechanistic components have been proven to contribute to increased cardiovascular morbidity and mortality in general.

The TFIID components human TAF(II)140 and Drosophila BIP2 (TAF(II)155) are novel metazoan homologues of yeast TAF(II)47 containing a histone fold and a PHD finger.

The RNA polymerase II transcription factor TFIID comprises the TATA binding protein (TBP) and a set of TBP-associated factors (TAF(II)s). TFIID has been extensively characterized for yeast, Drosophila, and humans, demonstrating a high degree of conservation of both the amino acid sequences of the constituent TAF(II)s and overall molecular organization. In recent years, it has been assumed that all the metazoan TAF(II)s have been identified, yet no metazoan homologues of yeast TAF(II)47 (yTAF(II)47) and yTAF(II)65 are known. Both of these yTAF(II)s contain a histone fold domain (HFD) which selectively heterodimerizes with that of yTAF(II)25. We have cloned a novel mouse protein, TAF(II)140, containing an HFD and a plant homeodomain (PHD) finger, which we demonstrated by immunoprecipitation to be a mammalian TFIID component. TAF(II)140 shows extensive sequence similarity to Drosophila BIP2 (dBIP2) (dTAF(II)155), which we also show to be a component of Drosophila TFIID. These proteins are metazoan homologues of yTAF(II)47 as their HFDs selectively heterodimerize with dTAF(II)24 and human TAF(II)30, metazoan homologues of yTAF(II)25. We further show that yTAF(II)65 shares two domains with the Drosophila Prodos protein, a recently described potential dTAF(II). These conserved domains are critical for yTAF(II)65 function in vivo. Our results therefore identify metazoan homologues of yTAF(II)47 and yTAF(II)65.

Fractal correlation properties of heart rate dynamics and adverse events in patients with implantable cardioverter-defibrillators.

The aim of this study was to determine the prognostic significance of nonlinear and standard heart rate (HR) variability parameters in predicting future adverse events (AEs) in patients with implantable cardioverter-defibrillators. In postinfarction studies, nonlinear measures of HR variability obtained from long-term electrocardiographic recordings have been suggested to be better predictors of adverse outcomes than conventional HR variability measures. Fifty-five high-risk patients with reduced left ventricular function and an implantable cardioverter-defibrillator had a 10-minute, high-resolution electrocardiographic recording after which they were followed for 25 months on average. Implantable cardioverter-defibrillator shock or death was determined as the end point. The SD of all normal-to-normal RR intervals, the square root of the mean squared differences of successive normal-to-normal RR intervals, and the proportion of interval differences of successive normal-to-normal RR intervals >50 ms, low-frequency and high-frequency powers of the power spectrum and their ratio were calculated as conventional measures of HR variability. The short-term scaling exponent (alpha(1)) and approximate entropy were determined as nonlinear measures of HR variability. AEs occurred in 23 patients (42%). Patients with AEs had significantly lower alpha(1) than event-free patients: 0.81 +/- 0.29 (mean +/- SD) versus 1.01 +/- 0.30 (p = 0.02). None of the other HR variability parameters differed significantly between patients with and without AEs. In the Cox proportional-hazards model including age, gender, ejection fraction, occurrence of ventricular tachyarrhythmia before defibrillator implantation, beta-blocker usage, and alpha(1), only alpha(1) was an independent predictor of AEs: hazard ratio 1.20 (95% confidence interval 1.03 to 1.39) for every 0.10 decrease in alpha(1) (p = 0.020). In conclusion, alpha(1) obtained from a 10-minute electrocardiographic recording yields important prognostic information about the risk of AEs in patients with implantable cardioverter-defibrillators.