Subtraction electrocardiography: Detection of ischemia-induced ST displacement without the need to identify the J point

AbstractBackgroundWhen triaging a patient with acute chest pain at first medical contact, an electrocardiogram (ECG) is routinely made and inspected for signs of myocardial ischemia. The guidelines recommend comparison of the acute and an earlier-made ECG, when available. No concrete recommendations for this comparison exist, neither is known how to handle J-point identification difficulties. Here we present a J-point independent method for such a comparison.MethodsAfter conversion to vectorcardiograms, baseline and acute ischemic ECGs after 3minutes of balloon occlusion during elective PCI were compared in 81 patients of the STAFF III ECG database. Baseline vectorcardiograms were subtracted from ischemic vectorcardiograms using either the QRS onsets or the J points as synchronization instants, yielding vector magnitude difference signals, ΔH. Output variables for the J-point synchronized differences were ΔH at the actual J point and at 20, 40, 60 and 80ms thereafter. Output variables for the onset-QRS synchronized differences were the ΔH at 80, 100, 120, 140 and 160ms after onset QRS. Finally, linear regressions of all combinations of ΔHJ+… versus ΔHQRS+… were made, and the best combination was identified.ResultsThe highest correlation, 0.93 (p<0.01), was found between ΔH 40ms after the J point and 160ms after the onset of the QRS complex. With a ΔH ischemia threshold of 0.05mV, 66/81 (J-point synchronized differences) and 68/81 (onset-QRS synchronized differences) subjects were above the ischemia threshold, corresponding to sensitivities of 81% and 84%, respectively.ConclusionOur current study opens an alternative way to detect cardiac ischemia without the need for human expertise for determination of the J point by measuring the difference vector magnitude at 160ms after the onset of the QRS complex

Advanced repeated structuring and learning procedure to detect acute myocardial ischemia in serial 12-lead ECGs

Objectives. Acute myocardial ischemia in the setting of acute coronary syndrome (ACS) may lead to myocardial infarction. Therefore, timely decisions, already in the pre-hospital phase, are crucial to preserving cardiac function as much as possible. Serial electrocardiography, a comparison of the acute electrocardiogram with a previously recorded (reference) ECG of the same patient, aids in identifying ischemia-induced electrocardiographic changes by correcting for interindividual ECG variability. Recently, the combination of deep learning and serial electrocardiography provided promising results in detecting emerging cardiac diseases; thus, the aim of our current study is the application of our novel Advanced Repeated Structuring and Learning Procedure (AdvRS&LP), specifically designed for acute myocardial ischemia detection in the pre-hospital phase by using serial ECG features. Approach. Data belong to the SUBTRACT study, which includes 1425 ECG pairs, 194 (14%) ACS patients, and 1035 (73%) controls. Each ECG pair was characterized by 28 serial features that, with sex and age, constituted the inputs of the AdvRS&LP, an automatic constructive procedure for creating supervised neural networks (NN). We created 100 NNs to compensate for statistical fluctuations due to random data divisions of a limited dataset. We compared the performance of the obtained NNs to a logistic regression (LR) procedure and the Glasgow program (Uni-G) in terms of area-under-the-curve (AUC) of the receiver-operating-characteristic curve, sensitivity (SE), and specificity (SP). Main Results. NNs (median AUC = 83%, median SE = 77%, and median SP = 89%) presented a statistically (P value lower than 0.05) higher testing performance than those presented by LR (median AUC = 80%, median SE = 67%, and median SP = 81%) and by the Uni-G algorithm (median SE = 72% and median SP = 82%). Significance. In conclusion, the positive results underscore the value of serial ECG comparison in ischemia detection, and NNs created by AdvRS&LP seem to be reliable tools in terms of generalization and clinical applicability.Cardiolog

24hour heart rate variability in shift workers: Impact of shift schedule

Abstract: 24-Hour Heart Rate Variability in Shift Workers: Impact of Shift Schedule: L.G.P.M. van AMELSVOORT, et al. Department of Epidemiology, Maastricht University-Disturbance of the circadian pattern of cardiac autonomic control by working at night when the physiological system anticipates rest could explain part of the elevated cardiovascular risk in shift workers. Analysis of Heart Rate Variability (HRV) is a non-invasive tool to estimate disturbances of the cardiac autonomic control. To assess the influence of working at night on cardiac autonomic control, HRV levels were determined in shift workers. 24-h ECG recordings were made during a day on morning shift and a day on night shift. Within person differences between a morning and a night shift were calculated. Possible modification of the reported effects by the shift schedule was determined. Significantly elevated mean %LF during sleep was found on a day worked on night shift compared with a day on day shift (%LF + 3.04, P&lt;0.01). Type of shift schedule was found to be a significant modifier of this effect. The difference in %LF between the night and day shift for the different shift schedules apart were: + 0.88% for the workers in the fast forward rotating shift, + 3.06% for the fast backward rotating shift, + 6.15% (P&lt;0.001) for the medium speed backward rotating shift and + 1.18% for the shift workers without a regular shift schedule. The results suggest an increased sympathetic dominance during a night shift sleep, indicating an inferior sleep quality. Optimisation of this schedule might diminish this impact and could contribute to a reduction of the cardiovascular disease risk among shift workers. (J Occup Health 2001; 43: 32-38

Reduced resting-state connectivity in areas involved in processing of face-related social cues in female adolescents with atypical anorexia nervosa.

Atypical anorexia nervosa (AN) has a high incidence in adolescents and can result in significant morbidity and mortality. Neuroimaging could improve our knowledge regarding the pathogenesis of eating disorders (EDs), however research on adolescents with EDs is limited. To date no neuroimaging studies have been conducted to investigate brain functional connectivity in atypical AN. We investigated resting-state functional connectivity using 3 T MRI in 22 drug-naïve adolescent patients with atypical AN, and 24 healthy controls. Psychological traits related to the ED and depressive symptoms have been assessed using the Eating Disorders Examination Questionnaire (EDE-Q) and the Montgomery-Åsberg Depression Rating Scale self-reported (MADRS-S) respectively. Reduced connectivity was found in patients in brain areas involved in face-processing and social cognition, such as the left putamen, the left occipital fusiform gyrus, and specific cerebellar lobules. The connectivity was, on the other hand, increased in patients compared with controls from the right inferior temporal gyrus to the superior parietal lobule and superior lateral occipital cortex. These areas are involved in multimodal stimuli integration, social rejection and anxiety. Patients scored higher on the EDE-Q and MADRS-S questionnaires, and the MADRS-S correlated with connectivity from the right inferior temporal gyrus to the superior parietal lobule in patients. Our findings point toward a role for an altered development of socio-emotional skills in the pathogenesis of atypical AN. Nonetheless, longitudinal studies will be needed to assess whether these connectivity alterations might be a neural marker of the pathology

Examining a staging model for anorexia nervosa: empirical exploration of a four stage model of severity.

Background: An illness staging model for anorexia nervosa (AN) has received increasing attention, but assessing the merits of this concept is dependent on empirically examining a model in clinical samples. Building on preliminary findings regarding the reliability and validity of the Clinician Administered Staging Instrument for Anorexia Nervosa (CASIAN), the current study explores operationalising CASIAN severity scores into stages and assesses their relationship with other clinical features. Method: In women with DSM-IV-R AN and sub-threshold AN (all met AN criteria using DSM 5), receiver operating curve (ROC) analysis (n = 67) assessed the relationship between the sensitivity and specificity of each stage of the CASIAN. Thereafter chi-square and post-hoc adjusted residual analysis provided a preliminary assessment of the validity of the stages comparing the relationship between stage and treatment intensity and AN sub-types, and explored movement between stages after six months (Time 3) in a larger cohort (n = 171). Results: The CASIAN significantly distinguished between milder stages of illness (Stage 1 and 2) versus more severe stages of illness (Stages 3 and 4), and approached statistical significance in distinguishing each of the four stages from one other. CASIAN Stages were significantly associated with treatment modality and primary diagnosis, and CASIAN Stage at Time 1 was significantly associated with Stage at 6 month follow-up. Conclusions: Provisional support is provided for a staging model in AN. Larger studies with longer follow-up of cases are now needed to replicate and extend these findings and evaluate the overall utility of staging as well as optimal staging models

Abnormalities in autonomic function in obese boys at-risk for insulin resistance and obstructive sleep apnea.

Study objectivesCurrent evidence in adults suggests that, independent of obesity, obstructive sleep apnea (OSA) can lead to autonomic dysfunction and impaired glucose metabolism, but these relationships are less clear in children. The purpose of this study was to investigate the associations among OSA, glucose metabolism, and daytime autonomic function in obese pediatric subjects.MethodsTwenty-three obese boys participated in: overnight polysomnography; a frequently sampled intravenous glucose tolerance test; and recordings of spontaneous cardiorespiratory data in both the supine (baseline) and standing (sympathetic stimulus) postures.ResultsBaseline systolic blood pressure and reactivity of low-frequency heart rate variability to postural stress correlated with insulin resistance, increased fasting glucose, and reduced beta-cell function, but not OSA severity. Baroreflex sensitivity reactivity was reduced with sleep fragmentation, but only for subjects with low insulin sensitivity and/or low first-phase insulin response to glucose.ConclusionsThese findings suggest that vascular sympathetic activity impairment is more strongly affected by metabolic dysfunction than by OSA severity, while blunted vagal autonomic function associated with sleep fragmentation in OSA is enhanced when metabolic dysfunction is also present

Cardiovascular dynamics in ischemic cardiomyopathy during exercise

Cardiac Dysfunction and Arrhythmia