- 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.
- 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.
- 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.
- 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.
- Abnormal P-Wave Axis and Ischemic Stroke: The ARIC Study (Atherosclerosis Risk In Communities). [Journal Article]
- SStroke 2017; 48(8):2060-2065
- CONCLUSIONS: aPWA is independently associated with ischemic stroke. This association seems to be stronger for cardioembolic strokes. Collectively, our findings suggest that alterations in atrial electric activation may predispose to cardiac thromboembolism independent of atrial fibrillation.
- Normal limits of the electrocardiogram derived from a large database of Brazilian primary care patients. [Journal Article]
- BCBMC Cardiovasc Disord 2017 Jun 13; 17(1):152
- CONCLUSIONS: This study has provided reference values for Latinos of both sexes older than 1 year. Our results are comparable to studies performed in different populations.
- Approach selection of radiofrequency catheter ablation for ventricular arrhythmias originating from the left ventricular summit: potential relevance of Pseudo Delta wave, Intrinsicoid deflection time, maximal deflection index. [Journal Article]
- BCBMC Cardiovasc Disord 2017 05 30; 17(1):140
- CONCLUSIONS: This retrospective study showed that VAs of left ventricular summit origin can be effectively cured with RFCA. For these VAs, prolonged PdW, IDT, MDI indicating RFCA by DGCV approach can be attempted firstly.
- Using Wavelet Entropy to Demonstrate how Mindfulness Practice Increases Coordination between Irregular Cerebral and Cardiac Activities. [Journal Article]
- JVJ Vis Exp 2017 May 10; (123)
- In both the East and West, traditional teachings say that the mind and heart are somehow closely correlated, especially during spiritual practice. One difficulty in proving this objectively is that t...
In both the East and West, traditional teachings say that the mind and heart are somehow closely correlated, especially during spiritual practice. One difficulty in proving this objectively is that the natures of brain and heart activities are quite different. In this paper, we propose a methodology that uses wavelet entropy to measure the chaotic levels of both electroencephalogram (EEG) and electrocardiogram (ECG) data and show how this may be used to explore the potential coordination between the mind and heart under different experimental conditions. Furthermore, Statistical Parametric Mapping (SPM) was used to identify the brain regions in which the EEG wavelet entropy was the most affected by the experimental conditions. As an illustration, the EEG and ECG were recorded under two different conditions (normal rest and mindful breathing) at the beginning of an 8-week standard Mindfulness-based Stress Reduction (MBSR) training course (pretest) and after the course (posttest). Using the proposed method, the results consistently showed that the wavelet entropy of the brain EEG decreased during the MBSR mindful breathing state as compared to that during the closed-eye resting state. Similarly, a lower wavelet entropy of heartrate was found during MBSR mindful breathing. However, no difference in wavelet entropy during MBSR mindful breathing was found between the pretest and posttest. No correlation was observed between the entropy of brain waves and the entropy of heartrate during normal rest in all participants, whereas a significant correlation was observed during MBSR mindful breathing. Additionally, the most well-correlated brain regions were located in the central areas of the brain. This study provides a methodology for the establishment of evidence that mindfulness practice (i.e., mindful breathing) may increase the coordination between mind and heart activities.
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- Electrocardiographic changes mimicking acute coronary syndrome in a large intracranial tumour: A diagnostic dilemma. [Case Reports]
- BCBMC Cardiovasc Disord 2017 Apr 04; 17(1):91
- CONCLUSIONS: The two mechanisms for ECG changes described in subarachnoid haemorrhage are the neurogenic stunned myocardium due to the catecholamine surge on the myocytes and stress cardiomyopathy. The same mechanisms could be the reasons for the ECG changes seen in intracranial tumours. These ECG changes could be easily misdiagnosed as acute coronary syndrome. This case emphasizes the importance of the cardiac biomarkers, 2D ECHO and coronary angiogram when confronted with such a diagnostic dilemma. Thus a more holistic analysis should be practiced in diagnosing acute coronary events in patients with intracranial pathologies to obviate a myriad of unnecessary investigations, interventions, costly treatment strategies which may well be detrimental to the patient.