Aim of the study was to find out which myocardial repolarization parameters predict reperfusion ventricular tachycardia and fibrillation (VT/VF) and determine how these parameters express in ECG.
Methods
Coronary occlusion and reperfusion (30/30 min) was induced in 24 cats. Local activation and end of repolarization times (RT) were measured in 88 intramyocardial leads. Computer simulations of precordial electrograms were performed.
Results
Reperfusion VT/VF developed in 10 animals. Arrhythmia-susceptible animals had longer RTs in perfused areas [183(177;202) vs 154(140;170) ms in susceptible and resistant animals, respectively, P < 0.05]. In logistic regression analysis, VT/VFs were associated with prolonged RTs in the perfused area (OR 1.068; 95% CI 1.012–1.128; P = 0.017). Simulations demonstrated that prolonged repolarization in the perfused/border zone caused precordial terminal T-wave inversion.
Conclusions
The reperfusion VT/VFs were independently predicted by the longer RT in the perfused zone, which was reflected in the terminal negative phase of the electrocardiographic T-wave. 相似文献
Feather mites are highly specialized permanent ectosymbionts recorded from all recently recognized bird orders. These mites, specialized to live in the plumage of their hosts, rarely cause any visible damage to their specific hosts. Recently described feather mite Allopsoroptoides galli Mironov (Acariformes: Psoroptoididae) was reported to cause severe mange in chickens in Brazil, leading to unprecedented economic losses. Until now, the natural host of A. galli remained unknown. In this paper, we report its true wild host, the Guira cuckoo Guira guira (Cuculiformes: Cuculidae). In addition, a previously unknown heteromorphic form of males is described from the mite population distributed on its natural host. We also speculate a possible scenario by which this mite species could have been horizontally transferred from the wild populations of the natural host to the secondary hosts. 相似文献
A recently proposed method is used to parameterize the nucleation‐driven kinetics of poly(ε‐caprolactone) melting. The method is based on fitting a theoretically derived temperature dependence of the effective activation energy to the experimental dependence obtained from the Kissinger plot. Although the theoretical dependence fits the experimental one accurately, the fit gives rise to a surface free energy that is significantly smaller than the one obtained from crystallization data. A similar result is reported in other publications that make use of a homogeneous nucleation model for polymer melting. It is argued that a heterogeneous nucleation model is a more appropriate representation of the melting process and that its use resolves the problem of estimating the unusually small surface free energies.
Differential scanning calorimetry (DSC) is used to study the kinetics of the coil‐to‐globule transition in aqueous solutions of poly(N‐isopropoylacrylamide) (PNIPAM) prepared in the bulk (3 and 10 wt%) and nanoconfined (10 wt% inside 30 nm silica pores) forms. It is demonstrated that the kinetics can be described in terms of the classical nucleation model. The proposed treatment affords estimating the free‐energy barrier and pre‐exponential factor of the transition. The application of the nucleation model to the DSC data collected for the three systems studied provides physical insights into the effect of increasing the transition temperature due to dilution and nanoconfinement. Dilution appears to raise the free‐energy barrier, whereas nanoconfinement causes a decrease in the pre‐exponential factor.
