- Establishment of methodology for non-invasive electrocardiographic measurements in turtles and tortoises. [Journal Article]
- AVActa Vet Hung 2018; 66(3):365-375
- The lack of knowledge on how to perform species-specific electrocardiographic (ECG) measurements in chelonians makes ECG evaluations difficult. The aim of this study was to establish non-invasive met...
The lack of knowledge on how to perform species-specific electrocardiographic (ECG) measurements in chelonians makes ECG evaluations difficult. The aim of this study was to establish non-invasive methods for ECG sample collection in different species of non-anaesthetised chelonians, focusing on adhesive and clamp electrodes. A total of 72 turtles and tortoises from 20 species and various sizes were used for the study. Body weight ranged from 32 g to 65 kg. From the aspect of specimen fixation, dorsal recumbency proved to be the most useful. Both adhesive and clamp electrodes yielded results when applied to the plastron and skin folds. Pre-emptive results suggest an indirect correlation with plastron thickness, the presence of a hinge, habitat and measurable ECG wave amplitude. ECG wave recordings are more likely in aquatic chelonians and species with a hinge. With size the plastron also thickens, making wave detection impossible. ECG waves were detected in 41 of the 72 specimens, complete PQRST complexes in 19 animals, with the rest showing absent P waves in all leads. ECG amplitudes were below 1 mV, with an average of 0.15 mV R wave amplitude.
- Clinical significance of fragmented QRS complexes or J waves in patients with idiopathic ventricular arrhythmias. [Journal Article]
- PlosPLoS One 2018; 13(4):e0194363
- CONCLUSIONS: Patients with IVF had higher prevalence of f-QRS or J waves. And patients with f-QRS or J waves were at higher risk of recurrent ventricular fibrillation.
- Treating her well. [Journal Article]
- EMEmerg Med J 2018; 35(4):246-247
- CLINICAL INTRODUCTION: A 44-year-old woman presents pain free to our ED after experiencing 45 min of tightening of the chest with radiation to her left arm, diaphoresis and nausea. Her vital signs a...
CLINICAL INTRODUCTION: A 44-year-old woman presents pain free to our ED after experiencing 45 min of tightening of the chest with radiation to her left arm, diaphoresis and nausea. Her vital signs are normal except for her high BP, which is 180/110. She reports recurrent episodes of chest pain in the past 1.5 weeks, unrelated to exercise. She visited a general practitioner who prescribed pain medication and treated her new-onset hypertension. Besides the recently found hypertension, heavy smoking is her only other traditional risk factor for cardiovascular disease.
- Predicting the cardiac toxicity of drugs using a novel multiscale exposure-response simulator. [Journal Article]
- CMComput Methods Biomech Biomed Engin 2018; 21(3):232-246
- A common but serious side effect of many drugs is torsades de pointes, a rhythm disorder that can have fatal consequences. Torsadogenic risk has traditionally been associated with blockage of a speci...
A common but serious side effect of many drugs is torsades de pointes, a rhythm disorder that can have fatal consequences. Torsadogenic risk has traditionally been associated with blockage of a specific potassium channel and an increased recovery period in the electrocardiogram. However, the mechanisms that trigger torsades de pointes remain incompletely understood. Here we establish a computational model to explore how drug-induced effects propagate from the single channel, via the single cell, to the whole heart level. Our mechanistic exposure-response simulator translates block-concentration characteristics for arbitrary drugs into three-dimensional excitation profiles and electrocardiogram recordings to rapidly assess torsadogenic risk. For the drug of dofetilide, we show that this risk is highly dose-dependent: at a concentration of 1x, QT prolongation is 55% but the heart maintains its regular sinus rhythm; at 5.7x, QT prolongation is 102% and the heart spontaneously transitions into torsades de points; at 30x, QT prolongation is 132% and the heart adapts a quasi-depolarized state with numerous rapidly flickering local excitations. Our simulations suggest that neither potassium channel blockage nor QT interval prolongation alone trigger torsades de pointes. The underlying mechanism predicted by our model is early afterdepolarization, which translates into pronounced U waves in the electrocardiogram, a signature that is correctly predicted by our model. Beyond the risk assessment of existing drugs, our exposure-response simulator can become a powerful tool to optimize the co-administration of drugs and, ultimately, guide the design of new drugs toward reducing life threatening drug-induced rhythm disorders in the heart.
- Pathological ECG that seemed normal following electrode misplacement. [Case Reports]
- BCBMJ Case Rep 2017 Dec 05; 2017
- We report the case of a 57-year-old woman found at home who received an ECG after having recovered from a seizure, without any clinical cardiac anomaly. The ECG revealed an elevation of the ST segmen...
We report the case of a 57-year-old woman found at home who received an ECG after having recovered from a seizure, without any clinical cardiac anomaly. The ECG revealed an elevation of the ST segment from the V1 to V5 leads and negative T waves from V1 to V5 leads. At her hospital admission, the emergency care unit (ECU) nurse performed another ECG. It no longer showed any repolarisation anomaly. However, the ECU nurse had put the precordial electrodes 3 cm too low, probably due to the patient's voluminous breasts. In the end, the pathological trace reappeared after we returned the electrodes to their initial positions. Malpositioning of the electrodes caused a seemingly normal ECG result with life-threatening consequences.
- Relationship between frequency spectrum of heart rate variability and autonomic nervous activities during sleep in newborns. [Journal Article]
- BDBrain Dev 2018; 40(3):165-171
- CONCLUSIONS: These results indicate that the autonomic patterns in active and quiet sleep of newborns are different from those in REM and non-REM sleep of adults and may be develop to the autonomic patterns in adults, and that parasympathetic activity is dominant during quiet sleep as compared to active sleep from the results of LFn and HFn in newborns. In addition, in some preterm infants, delayed development of the autonomic nervous system can be determined by classifying the autonomic nervous activity pattern of sleep stages.
- Non-contact and through-clothing measurement of the heart rate using ultrasound vibrocardiography. [Journal Article]
- MEMed Eng Phys 2017; 50:96-102
- We present a novel non-contact system for monitoring the heart rate on human subjects with clothes. Our approach is based on vibrocardiography, and measures locally skin displacements. Vibrocardiogra...
We present a novel non-contact system for monitoring the heart rate on human subjects with clothes. Our approach is based on vibrocardiography, and measures locally skin displacements. Vibrocardiography with a laser Doppler vibrometer already allows monitoring of this vital sign, but can only be used on bare skin and requires an expensive piece of equipment. We propose here to use an airborne pulse-Doppler ultrasound system operating in the 20-60 kHz range, and comprised of an emitter focusing the ultrasound pulses on skin and a microphone recording the reflected waves. Our implementation was validated in vitro and on two healthy human subjects, using simultaneously laser vibrocardiography and electrocardiography as references. Accurate measurements of the heart rate on clothed skin suggest that our non-contact ultrasonic method could be implemented both inside and outside the clinical environment, and therefore benefit both medical and safety applications.
- A female patient with hypokalaemia-induced J wave syndrome: An unusual case report. [Case Reports]
- MMedicine (Baltimore) 2017; 96(38):e8098
- CONCLUSIONS: This case tells us that hypokalaemia might induce J wave and elevated ST segments which should be distinguished from acute myocardial syndrome.
- Empirical evidence for the relationship between cognitive workload and attentional reserve. [Journal Article]
- IJInt J Psychophysiol 2017; 121:46-55
- While the concepts of cognitive workload and attentional reserve have been thought to have an inverse relationship for some time, such a relationship has never been empirically tested. This was the p...
While the concepts of cognitive workload and attentional reserve have been thought to have an inverse relationship for some time, such a relationship has never been empirically tested. This was the purpose of the present study. Aspects of the electroencephalogram were used to assess both cognitive workload and attentional reserve. Specifically, spectral measures of cortical activation were used to assess cognitive workload, while amplitudes of the event-related potential from the presentation of unattended "novel" sounds were used to assess attentional reserve. The relationship between these two families of measures was assessed using canonical correlation. Twenty-seven participants performed a flight simulator task under three levels of challenge. Verification of manipulation was performed using self-report measures of task demand, objective task performance, and heart rate variability using electrocardiography. Results revealed a strong, negative relationship between the spectral measures of cortical activation, believed to be representative of cognitive workload, and ERP amplitudes, believed to be representative of attentional reserve. This finding provides support for the theoretical and intuitive notion that cognitive workload and attentional reserve are inversely related. The practical implications of this result include improved state classification using advanced machine learning techniques, enhanced personnel selection/recruitment/placement, and augmented learning/training.
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- P-Wave Indices and Risk of Ischemic Stroke: A Systematic Review and Meta-Analysis. [Review]
- SStroke 2017; 48(8):2066-2072
- CONCLUSIONS: P-wave terminal force in lead V1, P-wave duration, and maximum P-wave area are useful electrocardiographic markers that can be used to stratify the risk of incident ischemic stroke.