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

Relation of overall and abdominal adiposity with electrocardiogram parameters of subclinical cardiovascular disease in individuals aged 45 to 65 years (from the Netherlands Epidemiology of Obesity Study)

Overall and abdominal obesity are well-established risk factors for cardiometabolic disease. However, associations of overall and abdominal adiposity with electrocardiographic (ECG) markers of subclinical cardiovascular disease (CVD) have not yet been fully elucidated. Therefore, we investigated these associations in a population without preexisting CVD. We performed cross-sectional analyses in the Netherlands Epidemiology of Obesity Study. Body mass index (BMI), total body fat, and waist circumference were assessed in all participants, and abdominal subcutaneous adipose tissue and visceral adipose tissue (by magnetic resonance imaging) were assessed in a random subgroup. ECG parameters were determined using 12-lead electrocardiograms. We performed linear regression analyses, adjusting for potential confounding factors and, when investigating abdominal adiposity, additionally for total body fat. After exclusion of participants with preexisting CVD (n = 654), 5,939 individuals (42% men) were analyzed, with a mean (SD) age of 55 (6) years and BMI of 26.3 (4.4) kg/m2. Measures of both overall and abdominal adiposity were associated with ECG parameters but none of these measures was more strongly associated than the others. For example, heart rate (beats/min) increased per SD higher BMI (2.2; 95% confidence interval 1.9,2.5), total body fat (2.9; 2.4,3.4), subcutaneous adipose tissue (2.3;1.7,2.9), waist circumference (2.1; 1.4,2.8), and visceral adipose tissue (1.7; 0.8,2.5). In subgroup analyses based on gender and cardiovascular risk factors, no consistent interactions were observed. In conclusion, in a middle-aged population without preexisting CVD, measures of both overall and abdominal adiposity were associated with ECG parameters. Future studies should evaluate the added value of adiposity measures in electrocardiography-based diagnoses and the prognostic value of adding adiposity measures to risk prediction tools

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

Corruption in the Middle East and the Limits of Conventional Approaches

Die Unzufriedenheit mit der verbreiteten Korruption war 2011/2012 eine wesentliche Ursache für die arabischen Unruhen und weitere Aufstände weltweit. Der Fall Jordanien zeigt allerdings, dass konventionelle Ansätze zur Bekämpfung von Korruption nicht ausreichen. Eine angemessene Strategie gegen Korruption muss diese als ein Problem der Verteilungsgerechtigkeit und nicht des Strafrechts verstehen. Wie in allen anderen arabischen Staaten ist die Unzufriedenheit in der Bevölkerung über die offensichtliche Korruption auch in Jordanien beträchtlich. Allerdings wird im Allgemeinen nicht über Fälle von Bestechung und Erpressung geklagt, die weniger häufig vorkommen, sondern über lokale Praktiken politischer Patronage und Begünstigung, die unter dem Begriff "Wasta" zusammengefasst werden. "Wasta" wurde bislang als Form der Korruption und strafrechtliches Problem angesehen, weshalb Versuche zur Eindämmung überwiegend ineffizient blieben: "Wasta"-Praktiken werden in der Regel nicht mit Rechtsverstößen verbunden, sondern bewegen sich innerhalb formal legaler Verfahren. Konventionelle Ansätze zur Bekämpfung von Korruption, die sich an rechtsstaatlichen Grundsätzen und Transparenz orientieren, sind deshalb nicht zielführend. Demokratisierung allein ist ebenfalls ungeeignet, das Problem „Wasta” zu lösen. In der parlamentarischen Praxis macht "Wasta" den Großteil der Aktivitäten aller Parlamentsmitglieder aus. Diese werden deshalb als persönliche Dienstleister für ihre Wahlbezirke und nicht als Mitglieder einer gesetzgebenden Körperschaft wahrgenommen. Gleichzeitig hält die Bevölkerung das Parlament für eine zutiefst korrupte Institution. "Wasta" wird problematisch, wenn diese Praxis zu einem ungleichen Zugang der Bürger zu öffentlichen Ressourcen führt. Statt sich nur auf politische und administrative Reformen zu konzentrieren, muss der Fokus der Bekämpfung auf den (Wieder-)Aufbau wohlfahrtsstaatlicher Strukturen gelegt werden, zu denen alle Bürger gleichermaßen Zugang haben

Cardiac autonomic neuropathy in patients with diabetes and no symptoms of coronary artery disease: comparison of 123I-metaiodobenzylguanidine myocardial scintigraphy and heart rate variability

PURPOSE The purpose of this study was to evaluate the prevalence of cardiac autonomic neuropathy (CAN) in a cohort of patients with type 2 diabetes, truly asymptomatic for coronary artery disease (CAD), using heart rate variability (HRV) and (123)I-metaiodobenzylguanidine ((123)I-mIBG) myocardial scintigraphy. METHODS The study group comprised 88 patients with type 2 diabetes prospectively recruited from an outpatient diabetes clinic. In all patients myocardial perfusion scintigraphy, CAN by HRV and (123)I-mIBG myocardial scintigraphy were performed. Two or more abnormal tests were defined as CAN-positive (ECG-based CAN) and one or fewer as CAN-negative. CAN assessed by (123)I-mIBG scintigraphy was defined as abnormal if the heart-to-mediastinum ratio was 25%, or the total defect score was >13. RESULTS The prevalence of CAN in patients asymptomatic for CAD with type 2 diabetes and normal myocardial perfusion assessed by HRV and (123)I-mIBG scintigraphy was respectively, 27% and 58%. Furthermore, in almost half of patients with normal HRV, (123)I-mIBG scintigraphy showed CAN. CONCLUSION The current study revealed a high prevalence of CAN in patients with type 2 diabetes. Secondly, disagreement between HRV and (123)I-mIBG scintigraphy for the assessment of CAN was observed.Cardiovascular Aspects of Radiolog

Multi-ancestry GWAS of the electrocardiographic PR interval identifies 202 loci underlying cardiac conduction

The electrocardiographic PR interval reflects atrioventricular conduction, and is associated with conduction abnormalities, pacemaker implantation, atrial fibrillation (AF), and cardiovascular mortality. Here we report a multi-ancestry (N=293,051) genome-wide association meta-analysis for the PR interval, discovering 202 loci of which 141 have not previously been reported. Variants at identified loci increase the percentage of heritability explained, from 33.5% to 62.6%. We observe enrichment for cardiac muscle developmental/contractile and cytoskeletal genes, highlighting key regulation processes for atrioventricular conduction. Additionally, 8 loci not previously reported harbor genes underlying inherited arrhythmic syndromes and/or cardiomyopathies suggesting a role for these genes in cardiovascular pathology in the general population. We show that polygenic predisposition to PR interval duration is an endophenotype for cardiovascular disease, including distal conduction disease, AF, and atrioventricular pre-excitation. These findings advance our understanding of the polygenic basis of cardiac conduction, and the genetic relationship between PR interval duration and cardiovascular disease. On the electrocardiogram, the PR interval reflects conduction from the atria to ventricles and also serves as risk indicator of cardiovascular morbidity and mortality. Here, the authors perform genome-wide meta-analyses for PR interval in multiple ancestries and identify 141 previously unreported genetic loci.Peer reviewe

ExomeChip-Wide Analysis of 95 626 Individuals Identifies 10 Novel Loci Associated With QT and JT Intervals

BACKGROUND: QT interval, measured through a standard ECG, captures the time it takes for the cardiac ventricles to depolarize and repolarize. JT interval is the component of the QT interval that reflects ventricular repolarization alone. Prolonged QT interval has been linked to higher risk of sudden cardiac arrest.METHODS AND RESULTS: We performed an ExomeChip-wide analysis for both QT and JT intervals, including 209 449 variants, both common and rare, in 17 341 genes from the Illumina Infinium HumanExome BeadChip. We identified 10 loci that modulate QT and JT interval duration that have not been previously reported in the literature using single-variant statistical models in a meta-analysis of 95 626 individuals from 23 cohorts (comprised 83 884 European ancestry individuals, 9610 blacks, 1382 Hispanics, and 750 Asians). This brings the total number of ventricular repolarization associated loci to 45. In addition, our approach of using coding variants has highlighted the role of 17 specific genes for involvement in ventricular repolarization, 7 of which are in novel loci.CONCLUSIONS: Our analyses show a role for myocyte internal structure and interconnections in modulating QT interval duration, adding to previous known roles of potassium, sodium, and calcium ion regulation, as well as autonomic control. We anticipate that these discoveries will open new paths to the goal of making novel remedies for the prevention of lethal ventricular arrhythmias and sudden cardiac arrest

Comparative Analysis of the Equivital EQ02 Lifemonitor with Holter Ambulatory ECG Device for Continuous Measurement of ECG, Heart Rate, and Heart Rate Variability: A Validation Study for Precision and Accuracy

Background: The Equivital (EQ02) is a multi-parameter telemetric device offering both real-time and/or retrospective, synchronized monitoring of ECG, HR and HRV, respiration, activity and temperature. Unlike the Holter, which is the gold standard for continuous ECG measurement, EQO2 continuously monitors ECG via electrodes interwoven in the textile of a wearable belt.Objective: To compare EQ02 with the Holter for continuous home measurement of ECG, heart rate (HR) and heart rate variability (HRV).Methods: Eighteen healthy participants wore, simultaneously for 24 hours, the Holter and EQ02 monitors. Per participant, averaged HR and HRV per 5 minutes from the two devices were compared using Pearson correlation, paired T-test and Blant-Altman analyses. Accuracy and precision metrics included mean absolute relative difference (MARD). Results: Artefact content of EQ02 data varied widely between (range 1.93% to 56.45%) and within (range 0.75% to 99.61%) participants. Comparing the EQ02 to the Holter, the Pearson correlations were respectively 0.724, 0.955 and 0.997 for datasets containing all data and data with <50% or <20% artefacts respectively. For datasets containing respectively all data, data with <50% or <20% artefacts, bias estimated by Bland-Altman analysis was -2.8, -1.0 and -0.8 beats per minute and 24h MARD was 7.08, 3.01 and 1.5. After selecting a three- hour stretch of data containing 1.15% artefacts, Pearson correlation was 0.786 for HRV measured as standard deviation of NN intervals (SDNN). Conclusions:Although the EQ02 can accurately measure ECG and HRV, its accuracy and precision is highly dependent on artefact content. This is a serious limitation for clinical use in individual patients. However, the advantages of the EQ02 (ability to simultaneously monitor several physiologic parameters) may outweigh its disadvantages (higher artefact load) for research purposes and/ or for home monitoring in larger groups of study participants. Further studies can be aimed at minimizing the artefacts

Position of ST-deviation measurements relative to the J-point: Impact for ischemia detection

There is no consensus about the time instant relative to the J point where ST deviation has to be measured for detection of acute ischemia in the ECG. We analyzed 53 ECGs, recorded preceding emergency catheterization of acute coronary syndrome patients with a completely occluded culprit artery (cases), and 88 control ECGs recorded in the cardiology outpatient clinic. ECG-amplitude measurements were made every 10 ms, between 20 ms before till 80 ms after the J point. STEMI-detection algorithms varied from the traditional STEMI criterion (elevations in at least two adjacent ECG leads), via the STEMI equivalent criterion (depressions in V2 and V3), to the most liberal STEMI-detection algorithm in which elevations as well as depressions in two adjacent leads were considered as signs of ischemia. Diagnostic accuracy was highest (93.6%) for the most liberal STEMI-detection algorithm at 10 ms after the J point; sensitivity was 94.3% and specificity was 93.2%. The results of our study suggest that STEMI detection close to the J point is optima

Intra-Individual Comparison of Sinus and Ectopic Beats Probing the Ventricular Gradient’s Activation Dependence

Wilson assumed that the ventricular gradient (VG) is independent of the ventricular activation order. This paradigm has often been refuted and was never convincingly corroborated. We sought to validate Wilson’s concept by intra-individual comparison of the VG of sinus beats and ectopic beats, thus assessing the effects of both altered ventricular conduction (caused by the ectopic focus) and restitution (caused by ectopic prematurity). We studied standard diagnostic ECGs of 118 patients with accidental extrasystoles: normally conducted supraventricular ectopic beats (SN, N = 6) and aberrantly conducted supraventricular ectopic beats (SA, N = 20) or ventricular ectopic beats (V, N = 92). In each patient, we computed the VG vectors of the predominant beat, VGp→, of the ectopic beat, VGe→, and of the VG difference vector, ΔVGep→, and compared their sizes. VGe→ of the SA and V ectopic beats were significantly larger than VGp→ (53.7 ± 25.0 vs. 47.8 ± 24.6 mV∙ms, respectively; p ΔVGep→ were three times larger than the difference of VGe→ and VGp→ (19.94 ± 9.76 vs. 5.94 mV∙ms, respectively), demonstrating differences in the VGp→ and VGe→ spatial directions. The amount of ectopic prematurity was not correlated with ΔVGep→, although the larger VG difference vectors were observed for the more premature (<80%) extrasystoles. Electrical restitution properties and electrotonic interactions likely explain our findings. We conclude that the concept of a conduction-independent VG should be tested at equal heart rates and without including premature extrasystoles