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Concept: Electrocardiography

444

Flexible, wearable sensing devices can yield important information about the underlying physiology of a human subject for applications in real-time health and fitness monitoring. Despite significant progress in the fabrication of flexible biosensors that naturally comply with the epidermis, most designs measure only a small number of physical or electrophysiological parameters, and neglect the rich chemical information available from biomarkers. Here, we introduce a skin-worn wearable hybrid sensing system that offers simultaneous real-time monitoring of a biochemical (lactate) and an electrophysiological signal (electrocardiogram), for more comprehensive fitness monitoring than from physical or electrophysiological sensors alone. The two sensing modalities, comprising a three-electrode amperometric lactate biosensor and a bipolar electrocardiogram sensor, are co-fabricated on a flexible substrate and mounted on the skin. Human experiments reveal that physiochemistry and electrophysiology can be measured simultaneously with negligible cross-talk, enabling a new class of hybrid sensing devices.

Concepts: Chemistry, Electrophysiology, Cardiac electrophysiology, Signal processing, Electroencephalography, Skin, Sensors, Electrocardiography

150

To assess the validity of RR intervals and short-term heart rate variability (HRV) data obtained from the Polar V800 heart rate monitor, in comparison to an electrocardiograph (ECG).

Concepts: Cardiology, Psychometrics, Heart rate, Electrocardiography, Heart rate variability, Heart rate monitor

73

The electroencephalogram (EEG) reflects brain electrical activity. A flat (isoelectric) EEG, which is usually recorded during very deep coma, is considered to be a turning point between a living brain and a deceased brain. Therefore the isoelectric EEG constitutes, together with evidence of irreversible structural brain damage, one of the criteria for the assessment of brain death. In this study we use EEG recordings for humans on the one hand, and on the other hand double simultaneous intracellular recordings in the cortex and hippocampus, combined with EEG, in cats. They serve to demonstrate that a novel brain phenomenon is observable in both humans and animals during coma that is deeper than the one reflected by the isoelectric EEG, and that this state is characterized by brain activity generated within the hippocampal formation. This new state was induced either by medication applied to postanoxic coma (in human) or by application of high doses of anesthesia (isoflurane in animals) leading to an EEG activity of quasi-rhythmic sharp waves which henceforth we propose to call ν-complexes (Nu-complexes). Using simultaneous intracellular recordings in vivo in the cortex and hippocampus (especially in the CA3 region) we demonstrate that ν-complexes arise in the hippocampus and are subsequently transmitted to the cortex. The genesis of a hippocampal ν-complex depends upon another hippocampal activity, known as ripple activity, which is not overtly detectable at the cortical level. Based on our observations, we propose a scenario of how self-oscillations in hippocampal neurons can lead to a whole brain phenomenon during coma.

Concepts: Brain, Electrophysiology, Cerebral cortex, Cerebrum, Hippocampus, Electroencephalography, Coma, Electrocardiography

48

Worldwide, more than 50 million ECGs are carried out annually. Studies show that the standard wrist-ankle placement method may produce poor quality ECGs. Factors including limb movement, tremor, anxiety, cold extremities cause artefacts (distortions of the baseline and ECG waveforms). A problem exists. Physicians face a challenge interpreting poor quality ECGs. Diagnostic delays occur. Patients are subjected to recalls; compassion initiated this study. Torso (modified) leads are favoured as they provide rapid acquisition of better quality ECGs, but cause erroneous electrocardiography. Investigators have not attempted to correct these errors. This study analyses the errors and aims to rectify them.

Concepts: Electroencephalography, Cultural studies, Metaphysics, Electrocardiography

29

Continuous Holter recordings are often used in thorough QT studies (TQTS), with multiple 10-second electrocardiograms (ECGs) visually selected around predesignated time points. The authors hypothesized that computer-automated ECG selection would reduce within-subject variability, improve study data precision, and increase study power. Using the moxifloxacin and placebo arms of a Holter-based crossover TQTS, the authors compared interval duration measurements (IDMs) from manually selected to computer-selected ECGs. All IDMs were made with a fully automated computer algorithm. Moxifloxacin-induced changes in baseline- and placebo-subtracted QT intervals were similar for manual and computer ECG selection. Mean 90% confidence intervals were narrower, and within-subject variability by mixed-model covariance was lower for computer-selected than for manual-selected ECGs. Computer ECG selection reduced the number of subjects needed to achieve 80% power by 40% to 50% over manual. Computer ECG selection returns accurate ddQTcF values with less measurement variability than manual ECG selection by a variety of metrics. This results in increased study power and reduces the number of subjects needed to achieve desired power, which represents a significant potential source cost savings in clinical drug trials.

Concepts: Algorithm, Clinical trial, Cardiology, Measurement, Genetic algorithm, Electrocardiography, Holter monitor, Alan Turing

28

This paper describes two fatalities, three non-fatal intentional and three accidental oral ingestions of yew (Taxus baccata) leaves. In all cases the post-mortem external examinations showed no signs of violence. Internal examinations revealed small green, needle-like particles on the tongue, in the esophagus and in the stomach. Yew leaves were also identified in the stomach contents, whereas Taxus leaves were cut into small pieces and then ingested in one case. The analytical method used was based on a liquid-liquid-extraction under alkaline conditions followed by LC-MS/MS analysis (QTRAP 5500). Chromatographic separation was achieved by HPLC on a Kinetex C18 2.6u (100×3)mm. The analytical method allows the simultaneous identification and quantification of the commercially available yew alkaloids taxoids (m/z): paclitaxel (854.2→105.0/286.1), 10-deacetyltaxol (10-DAT: 812.2→105.0/286.1), baccatin III (BAC III: 604.0→105.0/327.0), 10-deacetylbaccatin III (10-DAB III: 562.1→105.0/327.0), cephalomannine [taxol B] (562.1→105.0/327.0) and of 3,5-dimethoxyphenol (3,5-DMP: 155.0→111.9/122.9) also encompassing the qualitative analysis of the alkaloidal diterpenoids (Q1→194.0/107.0); reference mass spectra obtained from a yew leaves extract: monoacetyltaxine (MAT: 568.4), taxine B (584.2), monohydroxydiacetyltaxine (MHDAT: 626.4), triacetyltaxine (TAT: 652.4), monohydroxytriacetyltaxine (MHTAT: 668.4). In both fatalities, paclitaxel, 10-DAT and cephalomannine were not identified in urine, cardiac and femoral blood but all taxoids and 3,5-DMP were present in stomach content and excreted into the bile. In urine, highest 3,5-DMP concentration was 7500μg/L and 23,000μg/L after enzymatic hydrolysis, respectively. In intentional and accidental poisonings, when electrocardiogram (ECG) examinations revealed ventricular tachycardia and/or prolonged QRS intervals, taxines were identified in plasma/serum, even after the ingestion of a few number of yew leaves, when 3,5-dimethoxyphenol was not even found. According to the data from one near-fatal intentional poisoning, elimination half-life of MAT, TAXIN B, MHDAT and MHTAT in serum was calculated with 11-13h and taxines were detected up to t=+122h post-ingestion of approximately two handfuls of yew leaves.

Concepts: Ingestion, Digestive system, Stomach, Chromatography, Ventricular fibrillation, Electrocardiography, Taxus, Taxus baccata

28

Findings on electrocardiogram may hint that pulmonary embolism (PE) is present when interpreted in the proper context and lead to definitive imaging tests. However, it would be useful to know if electrocardiographic (ECG) abnormalities also occur in patients with pneumonia and whether these are similar to ECG changes with PE. The purpose of this investigation was to determine ECG findings in patients with pneumonia. We retrospectively evaluated 62 adults discharged with a diagnosis of pneumonia who had no previous cardiopulmonary disease and had electrocardiogram obtained during hospitalization. The most prevalent ECG abnormality, other than sinus tachycardia, was minor nonspecific ST-segment or T-wave changes occurring in 13 of 62 (21%). Right atrial enlargement occurred in 4 of 62 (6.5%). QRS abnormalities were observed in 24 of 62 (39%). Right-axis deviation and S(1)S(2)S(3) were the most prevalent QRS abnormalities, which occurred in 6 of 62 (9.7%). Complete right bundle branch block and S(1)Q(3)T(3) pattern occurred in 3 of 62 (4.8%). ECG abnormalities that were not present within 1 month previously or abnormalities that disappeared within 1 month included left-axis deviation, right-axis deviation, right atrial enlargement, right ventricular hypertrophy, S(1)S(2)S(3), S(1)Q(3)T(3), low-voltage QRS complexes, and nonspecific ST-segment or T-wave abnormalities. In conclusion, electrocardiogram in patients with pneumonia often shows QRS abnormalities or nonspecific ST-segment or T-wave changes. ECG findings are similar to ECG abnormalities in PE and electrocardiogram cannot assist in the differential diagnosis.

Concepts: Cardiology, Heart, Cardiac electrophysiology, Pulmonary artery, Ventricular fibrillation, Electrocardiography, Hyperkalemia, QRS complex

28

In this study, several electrocardiogram (ECG)-derived indices corresponding to both ventricular depolarization and repolarization were evaluated during acute myocardial ischemia in an experimental model of myocardial infarction produced by 40 min coronary balloon inflation in 13 pigs. Significant changes were rapidly observed from minute 4 after the start of coronary occlusion, achieving their maximum values between 11 and 22 min for depolarization and between 9 and 12 min for repolarization indices, respectively. Subsequently, these maximum changes started to decrease during the latter part of the occlusion. Depolarization changes associated with the second half of the QRS complex showed a significant but inverse correlation with the myocardium at risk (MaR) estimated by scintigraphic images. The correlation between MaR and changes of the downward slope of the QRS complex, [Formula: see text], evaluated at the two more relevant peaks observed during the occlusion, was r = -0.75, p < 0.01 and r = -0.79, p < 0.01 for the positive and negative deflections observed in [Formula: see text] temporal evolution, respectively. Repolarization changes, analyzed by evaluation of ST segment elevation at the main observed positive peak, also showed negative, however non-significant correlation with MaR: r = -0.34, p = 0.28. Our results suggest that changes evaluated in the latter part of the depolarization, such as those described by [Formula: see text], which are influenced by R-wave amplitude, QRS width and ST level variations simultaneously, correlate better with the amount of ischemia than other indices evaluated in the earlier part of depolarization or during the ST segment.

Concepts: Myocardial infarction, Atherosclerosis, Cardiology, Cardiac electrophysiology, Acute coronary syndrome, Ventricular fibrillation, Electrocardiography, QRS complex

27

Computerized interpretation of the electrocardiogram (CIE) was introduced to improve the correct interpretation of the electrocardiogram (ECG), facilitating health care decision making and reducing costs. Worldwide, millions of ECGs are recorded annually, with the majority automatically analyzed, followed by an immediate interpretation. Limitations in the diagnostic accuracy of CIE were soon recognized and still persist, despite ongoing improvement in ECG algorithms. Unfortunately, inexperienced physicians ordering the ECG may fail to recognize interpretation mistakes and accept the automated diagnosis without criticism. Clinical mismanagement may result, with the risk of exposing patients to useless investigations or potentially dangerous treatment. Consequently, CIE over-reading and confirmation by an experienced ECG reader are essential and are repeatedly recommended in published reports. Implementation of new ECG knowledge is also important. The current status of automated ECG interpretation is reviewed, with suggestions for improvement.

Concepts: Electrocardiography

27

Zigbee is expected to have an explosive growth in wireless medical monitoring systems because it possesses the advantages of low cost, safe power strength and easy deployment. However, little work focuses on solving the bottleneck issue at the Zigbee coordinator in a data-intensive system to guarantee transmission reliability of life-critical data. This paper proposes Coordinator Traffic Diffusion (CTD) method to redirect excessive traffic from Coordinator to the Sink in Electrocardiography (ECG) medical application. CTD router, which implements CTD design, automatically redirects ECG data traffic to the sink node without involving the Coordinator, and thus reliable real-time ECG monitoring service can be delivered precisely. CTD design is tested in both TI CC2530 Zigbee platform and NS2 simulation. Experiment result demonstrates CTD design can assist routers in successfully delivering real-time ECG data samples reliably with the best transmission rate, 24 Kbps. This performance cannot be achieved by the original Zigbee design.

Concepts: Cardiology, Reliability, Road transport, Electrocardiography, Bottleneck, Medical monitor, Redirect, Router