Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2013
A simple model of the right atrium of the human heart with the sinoatrial and atrioventricular nodes included.
Existing atrial models with detailed anatomical structure and multi-variable cardiac transmembrane current models are too complex to allow to combine an investigation of long time dycal properties of the heart rhythm with the ability to effectively simulate cardiac electrical activity during arrhythmia. Other ways of modeling need to be investigated. Moreover, many state-of-the-art models of the right atrium do not include an atrioventricular node (AVN) and only rarely--the sinoatrial node (SAN). ⋯ Our simulations support the hypothesis that the alternans of the conduction time between the atria and the ventricles in the AV orthodromic reciprocating tachycardia can occur within a single pathway. In the atrial parasystole simulation, we found a mathematical condition which allows for a rough estimation of the location of the parasystolic source within the atrium, both for simplified (planar) and the cylindrical geometry of the atrium. The planar and the cylindrical geometry yielded practically the same results of simulations.
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J Clin Monit Comput · Aug 2013
Analysis of a mathematical model of apoptosis: individual differences and malfunction in programmed cell death.
Apoptosis is an important area of research because of its role in keeping a mature multicellular organism's number of cells constant, hence, ensuring that the organism does not have cell accumulation that may transform into cancer with additional hallmarks. Firstly, we have carried out sensitivity analysis on an existing mathematical mitochondria-dependent apoptosis model to find out which parameters have a role in causing monostable cell survival, which may, in turn, lead to malfunction in apoptosis. We have then generated three base parameter sets that represent healthy cells. ⋯ For this treatment, the amount of proteasome inhibitor needed for caspase-3 activation may be different for hypothetical cells with a different pro- or anti-apoptotic protein defect. It is also found that caspase-3 can be activated by Bcl-2 inhibitor treatment only in those hypothetical malfunctioning cells with Bax deficiency but not in others. These results are in line with the view that molecular heterogeneity in individuals may be an important factor in determining the individuals' positive or negative responses to treatments.
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J Clin Monit Comput · Aug 2013
The use of heart rate variability for the early detection of treatable complications after aneurysmal subarachnoid hemorrhage.
High-grade aneurysmal subarachnoid hemorrhage patients are monitored in the ICU for up to 21 days, as they are at risk for complications such as vasospasm of cerebral arteries, cardiac arrhythmias and neurogenic stress cardiomyopathy. The diagnosis of these treatable complications is often delayed by the limitations of monitoring capabilities. We applied computational analysis to a cohort of 24 aneurysmal subarachnoid hemorrhage patients, to identify heart rate variability and ECG frequency profiles that may be potential biomarkers of severe vasospasm, reversible cardiomyopathy and death.
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J Clin Monit Comput · Jun 2013
Randomized Controlled TrialUltrasound-guided radial arterial cannulation: long axis/in-plane versus short axis/out-of-plane approaches?
Arterial cannulation with ultrasound (US) guidance increases the success rate and reduces complications. US-guided vascular access has two main approaches: long axis in-plane (LA-IP) and short axis out-of-plane (SA-OOP) approaches. The purpose of this study was to compare performance time and possible complications between two techniques. ⋯ Posterior wall damage during arterial cannulation were found in 30 patients with SA-OOP Group (56 %) and 11 patients with LA-IP Group (20 %), (p < 0.05). In our study, the use of LA-IP approach during US-guided radial artery cannulation has higher success rate at first insertion. We also found LA-IP approach results in shorter cannulation time and decreased the incidence of complications.