Screening for Atrial Fibrillation

Approximately 10% of ischemic strokes are associated with atrial fibrillation (AF) first diagnosed at the time of stroke. Detecting asymptomatic AF would provide an opportunity to prevent these strokes by instituting appropriate anticoagulation. The AF-SCREEN international collaboration was formed in September 2015 to promote discussion and research about AF screening as a strategy to reduce stroke and death and to provide advocacy for implementation of country-specific AF screening programs. During 2016, 60 expert members of AF-SCREEN, including physicians, nurses, allied health professionals, health economists, and patient advocates, were invited to prepare sections of a draft document. In August 2016, 51 members met in Rome to discuss the draft document and consider the key points arising from it using a Delphi process. These key points emphasize that screen-detected AF found at a single timepoint or by intermittent ECG recordings over 2 weeks is not a benign condition and, with additional stroke factors, carries sufficient risk of stroke to justify consideration of anticoagulation. With regard to the methods of mass screening, handheld ECG devices have the advantage of providing a verifiable ECG trace that guidelines require for AF diagnosis and would therefore be preferred as screening tools. Certain patient groups, such as those with recent embolic stroke of uncertain source (ESUS), require more intensive monitoring for AF. Settings for screening include various venues in both the community and the clinic, but they must be linked to a pathway for appropriate diagnosis and management for screening to be effective. It is recognized that health resources vary widely between countries and health systems, so the setting for AF screening should be both country- and health system-specific. Based on current knowledge, this white paper provides a strong case for AF screening now while recognizing that large randomized outcomes studies would be helpful to strengthen the evidence base.

Screening for depression in patients with coronary heart disease (data from the Heart and Soul Study)

Major depression is associated with adverse outcomes in patients who have coronary heart disease. How best to identify depression in busy cardiology practices is unknown. We compared the test characteristics of 4 depression screening instruments with an interview diagnosis of depression (Diagnostic Interview Schedule) in 1,024 outpatients who had coronary heart disease. Screening instruments were the 10-item Center for Epidemiologic Studies Depression Scale-10, the Patient Health Questionnaire-9, the Patient Health Questionnaire-2, and a simple 2-item instrument that asks (1) "During the past month, have you often been bothered by feeling down, depressed, or hopeless?" and (2) "During the past month, have you often been bothered by little interest or pleasure in doing things?" Of the 1,024 participants, 224 (22%) had major depression based on the Diagnostic Interview Schedule. Areas under the receiver-operating characteristic curves were similar for all instruments (range 0.84 to 0.87). In conclusion, a positive response to 1 of the 2 items was 90% sensitive and 69% specific for depression, with a negative likelihood ratio of 0.14. Thus, negative responses to the 2 items effectively ruled out depression. A score > or =10 on the Patient Health Questionnaire-9 was 54% sensitive and 90% specific, with a positive likelihood ratio of 5.4. Thus, a cutpoint > or =10 was virtually diagnostic for depression.

TP53 and progression from Barrett's metaplasia to oesophageal adenocarcinoma in a UK population cohort

BACKGROUND AND AIMS

Oesophageal adenocarcinoma frequently develops on a background of metaplastic Barrett's epithelium. The development of malignancy is accompanied by genetic alterations, which may be promising biomarkers of disease progression.

METHODS

A case control study was conducted nested within a large unselected population based cohort of Barrett's patients. Incident oesophageal malignancies and high grade dysplasias were identified. For each case up to five controls were matched on age, sex, and year of diagnosis. Biopsies from the time of diagnosis of Barrett's epithelium were stained immunohistochemically for TP53, cyclin D1, cyclooxygenase 2 (COX-2), and beta-catenin proteins.

RESULTS

Twenty nine incident oesophageal malignancies and six cases of high grade dysplasia were identified. The odds of diffuse or intense TP53 staining were substantially elevated in biopsies from patients who developed oesophageal adenocarcinoma compared with controls (odds ratio (OR) 11.7 (95% confidence interval (CI) 1.93, 71.4)). This difference was also present when all cases were considered (OR 8.42 (95% CI 2.37, 30.0). Despite the association with TP53 staining, only 32.4% of cases had an initial biopsy showing diffuse/intense TP53 staining. There were no significant associations between cyclin D1, COX-2, or beta-catenin staining and case control status. The OR for positive staining for both TP53 and COX-2 was markedly increased in cases compared with controls (OR 27.3 (95% CI 2.89, 257.0)) although only 15% of cases had positive staining for both markers.

CONCLUSIONS

Immunohistochemical detection of TP53 expression is a biomarker of malignant progression in Barrett's oesophagus but sensitivity is too low to act as a criterion to inform endoscopic surveillance strategies. Additional biomarkers are required which when combined with TP53 will identify, with adequate sensitivity and specificity, Barrett's patients who are at risk of developing cancer.

Validation of acute myocardial infarction in the Food and Drug Administration's Mini-Sentinel program

PURPOSE

To validate an algorithm based upon International Classification of Diseases, 9(th) revision, Clinical Modification (ICD-9-CM) codes for acute myocardial infarction (AMI) documented within the Mini-Sentinel Distributed Database (MSDD).

METHODS

Using an ICD-9-CM-based algorithm (hospitalized patients with 410.x0 or 410.x1 in primary position), we identified a random sample of potential cases of AMI in 2009 from four Data Partners participating in the Mini-Sentinel Program. Cardiologist reviewers used information abstracted from hospital records to assess the likelihood of an AMI diagnosis based on criteria from the Joint European Society of Cardiology and American College of Cardiology Global Task Force. Positive predictive values (PPVs) of the ICD-9-based algorithm were calculated.

RESULTS

Of the 153 potential cases of AMI identified, hospital records for 143 (93%) were retrieved and abstracted. Overall, the PPV was 86.0% (95% confidence interval; 79.2%, 91.2%). PPVs ranged from 76.3% to 94.3% across the four Data Partners.

CONCLUSIONS

The overall PPV of potential AMI cases, as identified using an ICD-9-CM-based algorithm, may be acceptable for safety surveillance; however, PPVs do vary across Data Partners. This validation effort provides a contemporary estimate of the reliability of this algorithm for use in future surveillance efforts conducted using the Food and Drug Administration's MSDD.

Individual differences in cognitive processes: towards an explanation of schizophrenic symptomatology

A study is reported that examined the relationship between a measure of schizophrenic-like characteristics (schizotypy) in normal subjects and cognitive inhibition. Both repetitive and semantic measures of priming were used. It was found that low schizotypes showed negative priming (i.e. longer reaction times to the re-presentation of initially ignored stimuli) while high schizotypes did not; high schizotypes exhibited semantic facilitation (i.e. shorter reaction times to previously ignored stimuli) but low schizotypes did not. A model is suggested, including both inhibitory and facilitatory processes, which can account for these findings. Theorizing about these processes is of interest as it may shed some light on the mechanisms involved in the specifically cognitive symptoms of schizophrenia.

Probucol and other antioxidants prevent the inhibition of endothelium-dependent relaxation by low density lipoproteins

Hypercholesterolaemia and atherosclerosis impair responses to endothelium-derived nitric oxide (EDRF) in human and animal coronary arteries, a dysfunction that correlates with elevated low density lipoproteins (LDL). Previous studies show that native LDL immediately and reversibly inhibit acetylcholine-evoked EDRF responses in rabbit aortic ring precontracted with noradrenaline or serotonin whereas Cu(2+)-oxidised LDL (oxLDL) inhibit relaxations after 30 min with a potency that varies with the donor. We now show that antioxidants, probucol (10 microM) and ascorbic acid (100 microM) in vitro, prevent the inhibition by native LDL, indicating that this effect involves free radicals. As expected, the antioxidants had no influence on the inhibition by oxLDL. Superoxide dismutase appeared to have no effect on the inhibition by native or oxLDL. The oral administration of probucol to selected volunteers also prevented the inhibition of relaxation by their native LDL. These preparations showed a diminished susceptibility to oxidation and their oxLDL caused a markedly reduced and always reversible inhibition of relaxation compared to the potent and sometimes irreversible inhibition prior to administration of the drug. We conclude that antioxidants such as probucol reduce the formation of free radicals and the oxidative modification of LDL that lead to the impairment of EDRF responses and may prevent this same dysfunction in hypercholesterolaemia and atherosclerosis.

Cardiac arrest in patients who smoke crack cocaine

The aim of the study is to determine the clinical features and outcomes of cocaine users admitted to the hospital after cardiac arrest and compare them with nonusers. Cocaine is associated with cardiovascular complications, including ventricular arrhythmias; however, resuscitated cardiac arrest in relation to cocaine use is not a well-defined clinical entity. We reviewed available hospital charts at San Francisco General Hospital with the International Classification of Diseases, Ninth Revision diagnosis of cardiac arrest and cocaine use from 1994 to 2006. Clinical features and outcomes of cocaine users were compared with those of randomly selected control patients and age-matched controls with resuscitated cardiac arrest without cocaine use. We identified 22 patients with resuscitated cardiac arrest in the setting of cocaine use. Their average age was 42 +/- 10 years, >20 years younger than nonusers (68 +/- 16 years, p <0.01). After cardiac arrest, 12 of 22 patients (55%) who used cocaine had complete neurologic recovery in contrast to only 3 of 20 unmatched controls (15%, p <0.01) and 7 of 41 age-matched controls (17%, p <0.01). Only 10 of 22 cocaine users (46%) died compared with 15 of 20 unmatched controls (75%, p = 0.05) and 32 of 41 age-matched controls (78%, p <0.01). In a combined analysis of all patients, cocaine use was the only significant predictor of neurologic recovery (p <0.01) and survival (p <0.01). In conclusion, cocaine use is associated with cardiac arrest. In patients with cardiac arrest, cocaine users are younger than nonusers and more likely to survive with neurologic recovery, even compared with age-matched controls with cardiac arrest.

Association of Circulating Ceramides With Cardiac Structure and Function in the Community: The Framingham Heart Study

Background

A higher circulating plasma ceramide ratio (C16:0/C24:0) is associated with an increased risk of heart failure, even after accounting for standard risk factors including lipid markers. However, the pathobiological mechanisms that underlie this association are incompletely understood. We tested the hypothesis that plasma ceramide ratio (C16:0/C24:0) is associated with adverse cardiac remodeling in the community.

Methods and Results

We evaluated 2652 Framingham Offspring Study participants (mean age, 66±9 years; 55% women) who attended their eighth examination cycle and underwent routine echocardiography and liquid chromatography–tandem mass spectrometry–based assays for circulating ceramide concentrations. We used multivariable linear regression models to relate C16:0/C24:0 (independent variable) to the following echocardiographic measures (dependent variables; separate models for each): left ventricular mass, left ventricular ejection fraction, left atrial emptying fraction, left atrial end‐systolic volume, E/e′ (a measure of left ventricular diastolic function), and left ventricular global circumferential and longitudinal strain by speckle‐tracking echocardiography. In multivariable‐adjusted analyses, higher C16:0/C24:0 per standard deviation increment was associated with lower left ventricular ejection fraction (0.991‐fold change in left ventricular ejection fraction; P=0.0004), worse global circumferential strain (β=0.34, P=0.004), higher left atrial end‐systolic volume (β=2.48, p<0.0001), and lower left atrial emptying fraction (0.99‐fold change; P<0.0001). The C16:0/C24:0 ratio was not associated with either E/e′ or global longitudinal strain, and the association with higher left ventricular mass was rendered statistically nonsignificant upon correction for multiple comparisons.

Conclusions

Our cross‐sectional observations in a large community‐based sample are consistent with a potential detrimental impact of higher ceramide ratio (C16:0/24:0) on cardiac remodeling traits, which may partly explain the associations of these molecular species with clinical heart failure.

Photoplethysmograph signal reconstruction based on a novel motion artifact detection-reduction approach. Part II: Motion and noise artifact removal

We introduce a new method to reconstruct motion and noise artifact (MNA) contaminated photoplethysmogram (PPG) data. A method to detect MNA corrupted data is provided in a companion paper. Our reconstruction algorithm is based on an iterative motion artifact removal (IMAR) approach, which utilizes the singular spectral analysis algorithm to remove MNA artifacts so that the most accurate estimates of uncorrupted heart rates (HRs) and arterial oxygen saturation (SpO2) values recorded by a pulse oximeter can be derived. Using both computer simulations and three different experimental data sets, we show that the proposed IMAR approach can reliably reconstruct MNA corrupted data segments, as the estimated HR and SpO2 values do not significantly deviate from the uncorrupted reference measurements. Comparison of the accuracy of reconstruction of the MNA corrupted data segments between our IMAR approach and the time-domain independent component analysis (TD-ICA) is made for all data sets as the latter method has been shown to provide good performance. For simulated data, there were no significant differences in the reconstructed HR and SpO2 values starting from 10 dB down to -15 dB for both white and colored noise contaminated PPG data using IMAR; for TD-ICA, significant differences were observed starting at 10 dB. Two experimental PPG data sets were created with contrived MNA by having subjects perform random forehead and rapid side-to-side finger movements show that; the performance of the IMAR approach on these data sets was quite accurate as non-significant differences in the reconstructed HR and SpO2 were found compared to non-contaminated reference values, in most subjects. In comparison, the accuracy of the TD-ICA was poor as there were significant differences in reconstructed HR and SpO2 values in most subjects. For non-contrived MNA corrupted PPG data, which were collected with subjects performing walking and stair climbing tasks, the IMAR significantly outperformed TD-ICA as the former method provided HR and SpO2 values that were non-significantly different than MNA free reference values.

Regional variations in endothelin-1 and its receptor subtypes in human coronary vasculature: pathophysiological implications in coronary disease

Endothelin-1 is a potent vasoconstrictor peptide and mitogen for vascular smooth muscle cells. Increased plasma or tissue levels of endothelin-1 have been described after myocardial infarction and in atherosclerosis, suggesting that this peptide may play a pathophysiological role in various coronary syndromes. Here, we have studied regional variations in ET-1 and its receptors in control and atherosclerotic human coronary vasculature using standard immunohistochemistry and in vitro autoradiography. ET-1 immunoreactivity was associated with luminal endothelial cells and smooth muscle cells at regions of atherosclerosis. ET(A) receptors were present on smooth muscle cells of coronary arteries and on cardiac myocytes. Medial ET(B) receptor binding at the proximal region of coronary arteries was weak, but increased significantly towards distal regions of this vessel (p<0.005 in control and p<0.0005 in ischaemic heart disease). Microvascular endothelial cells in the adventitia of coronary arteries, myocardial microvessels and the endocardial endothelium expressed the ET(B) receptor exclusively. The receptor variations revealed in this study provide supporting evidence that ET-1 is associated with (1) vascular smooth muscle and endothelial cell proliferation, including areas of intimal hyperplasia and regions of neovascularization (2) increased ET-1-induced reactivity of distal portions of the human coronary artery, (3) ET-1-mediated constriction of myocardial microvessels. These results provide new insights into different potential roles for this peptide in healthy and diseased human coronary vasculature.

Comparison of Rapid Antigen Tests' Performance Between Delta and Omicron Variants of SARS-CoV-2 : A Secondary Analysis From a Serial Home Self-testing Study

BACKGROUND

It is important to document the performance of rapid antigen tests (Ag-RDTs) in detecting SARS-CoV-2 variants.

OBJECTIVE

To compare the performance of Ag-RDTs in detecting the Delta (B.1.617.2) and Omicron (B.1.1.529) variants of SARS-CoV-2.

DESIGN

Secondary analysis of a prospective cohort study that enrolled participants between 18 October 2021 and 24 January 2022. Participants did Ag-RDTs and collected samples for reverse transcriptase polymerase chain reaction (RT-PCR) testing every 48 hours for 15 days.

SETTING

The parent study enrolled participants throughout the mainland United States through a digital platform. All participants self-collected anterior nasal swabs for rapid antigen testing and RT-PCR testing. All Ag-RDTs were completed at home, whereas nasal swabs for RT-PCR were shipped to a central laboratory.

PARTICIPANTS

Of 7349 participants enrolled in the parent study, 5779 asymptomatic persons who tested negative for SARS-CoV-2 on day 1 of the study were eligible for this substudy.

MEASUREMENTS

Sensitivity of Ag-RDTs on the same day as the first positive (index) RT-PCR result and 48 hours after the first positive RT-PCR result.

RESULTS

A total of 207 participants were positive on RT-PCR (58 Delta, 149 Omicron). Differences in sensitivity between variants were not statistically significant (same day: Delta, 15.5% [95% CI, 6.2% to 24.8%] vs. Omicron, 22.1% [CI, 15.5% to 28.8%]; at 48 hours: Delta, 44.8% [CI, 32.0% to 57.6%] vs. Omicron, 49.7% [CI, 41.6% to 57.6%]). Among 109 participants who had RT-PCR-positive results for 48 hours, rapid antigen sensitivity did not differ significantly between Delta- and Omicron-infected participants (48-hour sensitivity: Delta, 81.5% [CI, 66.8% to 96.1%] vs. Omicron, 78.0% [CI, 69.1% to 87.0%]). Only 7.2% of the 69 participants with RT-PCR-positive results for shorter than 48 hours tested positive by Ag-RDT within 1 week; those with Delta infections remained consistently negative on Ag-RDTs.

LIMITATION

A testing frequency of 48 hours does not allow a finer temporal resolution of the analysis of test performance, and the results of Ag-RDTs are based on self-report.

CONCLUSION

The performance of Ag-RDTs in persons infected with the SARS-CoV-2 Omicron variant is not inferior to that in persons with Delta infections. Serial testing improved the sensitivity of Ag-RDTs for both variants. The performance of rapid antigen testing varies on the basis of duration of RT-PCR positivity.

PRIMARY FUNDING SOURCE

National Heart, Lung, and Blood Institute of the National Institutes of Health.

Recent trends in post-discharge mortality among patients with an initial acute myocardial infarction

The objectives of this study were to describe contemporary postdischarge death rates of patients hospitalized at all Worcester, Massachusetts, hospitals after initial acute myocardial infarctions (AMIs) and to examine factors associated with a poor prognosis. The medical records of patients discharged from 11 central Massachusetts medical centers after initial AMIs during 2001, 2003, 2005, and 2007 were reviewed, identifying 2,452 patients. This population was composed of predominantly older patients, men (58%), and whites. Overall, the 3-month, 1-year, and 2-year all-cause death rates were 8.9%, 16.4%, and 23.4%, respectively. Over time, reductions in postdischarge mortality were observed in crude as well as multivariate-adjusted analyses. In 2001, the 3-month, 1-year, and 2-year all-cause death rates were 11.1%, 17.1%, and 25.6%, respectively, compared to rates of 7.9%, 12.7%, and 18.6% in patients discharged in 2007. Older age, male gender, hospitalization for a non-ST-segment elevation AMI, renal dysfunction, and preexisting heart failure were associated with an increased risk for dying after hospital discharge. These results suggest that the postdischarge prognosis of patients with initial AMIs has improved, likely reflecting enhanced in-hospital and postdischarge management practices. In conclusion, patients with initial AMIs can also be identified who are at increased risk for dying after hospital discharge, in whom increased surveillance and targeted treatment approaches can be directed.

Astrocytic control of extracellular GABA drives circadian timekeeping in the suprachiasmatic nucleus

The hypothalamic suprachiasmatic nucleus (SCN) is the master mammalian circadian clock. Its cell-autonomous timing mechanism, a transcriptional/translational feedback loop (TTFL), drives daily peaks of neuronal electrical activity, which in turn control circadian behavior. Intercellular signals, mediated by neuropeptides, synchronize and amplify TTFL and electrical rhythms across the circuit. SCN neurons are GABAergic, but the role of GABA in circuit-level timekeeping is unclear. How can a GABAergic circuit sustain circadian cycles of electrical activity, when such increased neuronal firing should become inhibitory to the network? To explore this paradox, we show that SCN slices expressing the GABA sensor iGABASnFR demonstrate a circadian oscillation of extracellular GABA ([GABA]e) that, counterintuitively, runs in antiphase to neuronal activity, with a prolonged peak in circadian night and a pronounced trough in circadian day. Resolving this unexpected relationship, we found that [GABA]e is regulated by GABA transporters (GATs), with uptake peaking during circadian day, hence the daytime trough and nighttime peak. This uptake is mediated by the astrocytically expressed transporter GAT3 (Slc6a11), expression of which is circadian-regulated, being elevated in daytime. Clearance of [GABA]e in circadian day facilitates neuronal firing and is necessary for circadian release of the neuropeptide vasoactive intestinal peptide, a critical regulator of TTFL and circuit-level rhythmicity. Finally, we show that genetic complementation of the astrocytic TTFL alone, in otherwise clockless SCN, is sufficient to drive [GABA]e rhythms and control network timekeeping. Thus, astrocytic clocks maintain the SCN circadian clockwork by temporally controlling GABAergic inhibition of SCN neurons.

Association of cystatin C with poor exercise capacity and heart rate recovery: data from the heart and soul study

BACKGROUND

Cystatin C, an alternative serum measure of kidney function, is a stronger predictor of cardiovascular events than creatinine or estimated glomerular filtration rate (eGFR). We hypothesized that serum cystatin C concentration would have a stronger more linear association with cardiovascular functional status than creatinine-based measures in outpatients with established coronary heart disease (CHD).

METHODS

We measured serum cystatin C, serum creatinine, and eGFR in 906 outpatients with established CHD. We examined the association of these 3 measures of kidney function with treadmill exercise capacity (metabolic equivalent tasks achieved) and heart rate recovery (HRR) between peak and 1 minute after exercise by using linear and logistic regression.

RESULTS

Higher cystatin C concentrations were associated linearly with worse treadmill exercise capacity and HRR. The proportion of participants with poor exercise capacity (metabolic equivalent tasks achieved < 5) was 45% (99 of 222 participants) among those with cystatin C levels in the highest quartile (>1.30 mg/L) compared with 12% (29 of 241 participants) among those with cystatin C levels in the lowest quartile (<0.92 mg/L; adjusted odds ratio, 3.2; 95% confidence interval, 1.6 to 6.5; P = 0.001). The proportion of participants with poor HRR (<16 beats/min) was 42% (92 of 214 participants) among those with cystatin C levels in the highest quartile compared with 16% (37 of 238 participants) among those with cystatin C levels in the lowest quartile (adjusted odds ratio, 2.2; 95% confidence interval, 1.2 to 4.0; P = 0.01). The lowest quartile of eGFR (<61.8 mL/min [<1.03 mL/s]) was associated with decreased exercise capacity and prolonged HRR, but no difference was observed across the upper 3 quartiles of eGFR.

CONCLUSION

In patients with established CHD, cystatin C concentrations are associated linearly with worse exercise capacity and HRR. Cystatin C detects an association of impaired kidney function with decreased HRR and exercise capacity that is not fully captured using creatinine-based measurements.

Low rate of sex-specific result reporting in cardiovascular trials

OBJECTIVE

To explore the extent to which sex-specific result (SSR) reporting appears in recently published cardiovascular studies.

METHODS

All original adult cardiovascular clinical trials published in Annals of Internal Medicine, Archives of Internal Medicine, Journal of the American Medical Association, The New England Journal of Medicine, Journal of the American College of Cardiology, The American Journal of Cardiology, and Circulation from July 1 through December 31, 2004, were reviewed. Sex-specific result reporting was defined as presenting primary outcomes for women in a format to allow the data to be abstracted for use in a meta-analysis.

RESULTS

Of the 645 studies reviewed, 17 were excluded because they were appropriately single-sex trials. Of the remaining 628 studies, only 153 (24%) provided SSRs. The percentage of studies reporting SSRs was 37% (23/62) for general medical journals and 23% (130/566) for cardiovascular journals (P = .10). Among National Institutes of Health (NIH)-sponsored research, 31 (51%) of 61 trials analyzed outcomes by sex compared with 125 (22%) of 567 trials not sponsored by the NIH (P < .01).

CONCLUSION

Only a few current cardiovascular trials provide sex-specific data. Sex differences remain poorly understood, and this deficiency limits our ability to optimize medical care for both sexes. The stipulation that SSRs be investigated has led to significantly more SSR reporting in NIH-funded research. A parallel mandate by journal editors that requires authors to provide sex-specific data and analysis may help to bridge this knowledge gap.

High Burden of Unrecognized Atrial Fibrillation in Rural India: An Innovative Community-Based Cross-Sectional Screening Program

BACKGROUND

Atrial fibrillation, the world's most common arrhythmia, is a leading risk factor for stroke, a disease striking nearly 1.6 million Indians annually. Early detection and management of atrial fibrillation is a promising opportunity to prevent stroke but widespread screening programs in limited resource settings using conventional methods is difficult and costly.

OBJECTIVE

The objective of this study is to screen people for atrial fibrillation in rural western India using a US Food and Drug Administration-approved single-lead electrocardiography device, Alivecor.

METHODS

Residents from 6 villages in Anand District, Gujarat, India, comprised the base population. After obtaining informed consent, a team of trained research coordinators and community health workers enrolled a total of 354 participants aged 50 years and older and screened them at their residences using Alivecor for 2 minutes on 5 consecutive days over a period of 6 weeks beginning June, 2015.

RESULTS

Almost two-thirds of study participants were 55 years or older, nearly half were female, one-third did not receive any formal education, and more than one-half were from households earning less than US $2 per day. Twelve participants screened positive for atrial fibrillation yielding a sample prevalence of 5.1% (95% CI 2.7-8.7). Only one participant had persistent atrial fibrillation throughout all of the screenings, and 9 screened positive only once.

CONCLUSIONS

Our study suggests a prevalence of atrial fibrillation in this Indian region (5.1%) that is markedly higher than has been previously reported in India and similar to the prevalence estimates reported in studies of persons from North America and Europe. Historically low reported burden of atrial fibrillation among individuals from low and middle-income countries may be due to a lack of routine screening. Mobile technologies may help overcome resource limitations for atrial fibrillation screening in underserved and low-resource settings.

MRI in schizophrenia: basal ganglia and white matter T1 times

The T1 relaxation time of the basal ganglia (putamen, globus pallidus and head of caudate) and of the frontoparietal centrum semiovale was compared between 49 schizophrenic patients and 36 healthy controls. Previous reports of increased T1 time in the basal ganglia were not confirmed, and group differences were not detected within the white matter. Within patients T1 values could not be related to tardive dyskinesia or other clinical features. Normal variation seen in basal ganglia T1 times is described for the first time: lowest values occur in the globus pallidus and highest in the caudate, and values within the putamen increase rostrally.

A case of lymphomatoid granulomatosis masquerading as a lung abscess

Lymphomatoid granulomatosis (LG) is a rare T cell rich, B cell non-Hodgkin's lymphoma which is difficult to diagnose. We present a patient with LG who demonstrated many of the difficulties in diagnosis and highlighted the importance of reviewing the diagnosis if treatment does not have the anticipated effect.

Micro-RNAs Are Related to Epicardial Adipose Tissue in Participants With Atrial Fibrillation: Data From the MiRhythm Study

Introduction: Epicardial adipose tissue (EAT) has been linked to incidence and recurrence of atrial fibrillation (AF), but the underlying mechanisms that mediate this association remain unclear. Circulating microRNAs (miRNAs) contribute to the regulation of gene expression in cardiovascular diseases, including AF. Thus, we sought to test the hypothesis that circulating miRNAs relate to burden of EAT.

Methods: We examined the plasma miRNA profiles of 91 participants from the miRhythm study, an ongoing study examining associations between miRNA and AF. We quantified plasma expression of 86 unique miRNAs commonly expressed in cardiomyocytes using quantitative reverse transcriptase polymerase chain reaction (qPCR). From computed tomography, we used validated methods to quantify the EAT area surrounding the left atrium (LA) and indexed it to body surface area (BSA) to calculate indexed LA EAT (iLAEAT). Participants were divided into tertiles of iLAEAT to identify associations with unique miRNAs. We performed logistic regression analyses adjusting for factors associated with AF to examine relations between iLAEAT and miRNA. We performed further bioinformatics analysis of miRNA predicted target genes to identify potential molecular pathways are regulated by the miRNAs.

Results: The mean age of the participants was 59 ± 9, 35% were women, and 97% were Caucasian. Participants in the highest tertile of iLAEAT were more likely to have hypertension, heart failure, and thick posterior walls. In regression analyses, we found that miRNAs 155-5p (p < 0.001) and 302a-3p (p < 0.001) were significantly associated with iLAEAT in patients with AF. The predicted targets of the miRNAs identified were implicated in the regulation of cardiac hypertrophy, adipogenesis, interleukin-8 (IL-8), and nerve growth factor (NGF) signaling.

Conclusion: miRNA as well as EAT have previously been linked to AF. Our finding that iLAEAT and miRNAs 155-5p and 302a-3p are associated suggest a possible direct link to between these entities in the development and maintenance of AF. Further research is needed to study causal relationships between these biomarkers.

Atrial Fibrillation detection using time-varying coherence function and Shannon Entropy

We introduce a novel method for automatic detection of Atrial Fibrillation (AF) using time-varying coherence functions (TVCF) and Shannon Entropy (SE). The TVCF is estimated by the multiplication of two time-varying transfer functions (TVTFs). Two TVTFs are obtained using two adjacent data segments with one data segment as the input signal and the other data segment as the output to produce the first TVTF; the second TVTF is produced by reversing the input and output signals. The detection algorithm was tested on RR interval time series derived from two databases: the MIT-BIH Atrial Fibrillation (AF) and the MIT-BIH normal sinus rhythm (NSR). The MIT-BIH database contains a variety of short and long AF beats from 25 subjects and the MIT-BIH NSR database consists of only normal sinus rhythms from 18 subjects. Using the receiver operating characteristic curves from the combination of TVCF and SE, we obtained the accuracy of 97.49%, sensitivity of 97.41% and specificity of 97.54% for the MIT-BIH AF database. Furthermore, the specificity of the MIT-BIH NSR database was 100%.