冠心病中医辨证与QT和JT离散度的关系

目的:探讨冠心病中医辨证分型与QT离散度(QTd)和JT离散度(JTd)的关系.方法:110例经选择性冠状动脉(冠脉)造影术确定冠脉狭窄程度≥50%的冠心病患者,按中医辨证分为心血瘀阻型、痰浊内阻型、阴寒凝滞型、阳气虚衰型,心肾阴虚型和气阴两虚型.比较中医分型中偏实型组和偏虚型组以及6个证型间的QTd、JTd和校正QTd(QTcd)和校正JTd(JTcd).结果:偏实型组患者的QTd、JTd、QTcd和JTcd大于偏虚型组患者(P均＜0.01).在偏实型组中,心血瘀阻型的QTd、JTd、QTcd和JTcd大于痰浊内阻型和阴寒凝滞型(P均＜0.05).在偏虚型组中,阳气虚衰型的QTd、JTd、QTcd和JTcd大于心肾阴虚型和气阴两虚型(P均＜0.05).在6个证型中,心血瘀阻型QTd、JTd、QTcd和JTcd最大(P＜0.05或P＜0.01).结论:冠心病中医辨证分型中偏实型组QTd、JTd、QTcd和JTcd大于偏虚型组,说明偏实型组比偏虚型组患者心肌缺血重,易发生心律失常;心血瘀阻型患者的QTd、JTd、QTcd和JTcd最大,表明此型患者病情较重,易发生心律失常,属中医辨证分型中高危人群.     

心室复极指标对急性心肌梗死恶性室性心律失常的预测价值

目的:探讨J波、ST段墓碑型抬高、Q-T间期离散度(QTd)、J-T间期离散度(JTd)预测急性心肌梗死(AMI)后恶性室性心律失常的价值.方法:回顾性分析2000年1月至2010年12月住院临床确诊的173例急性ST段抬高型心肌梗死患者的心电图(ECG)及其相关资料,根据ECG结果分为J波组(n=57)、ST段墓碑型抬高组(n=52,其中26例兼有J波出现)和通常组(n=90),J波组、ST段墓碑型抬高组分别与通常组比较QTd、JTd及恶性室性心律失常的发生率.结果:J波组、ST段墓碑型抬高组的QTd、JTd分别为(75.1+22.0)ms、(72.9±23.9)ms和(71.4±21.3)ms、(69.0±25.0),均明显高于通常组的(59.0±17.9)ms和(53.3±18.4)ms,P均＜0.01;J波组、ST段墓碑型抬高组的恶性室性心律失常的发生率分别为31.6％、28.8％,均明显高于通常组的10％,P均＜0.01.结论:心电图心室复极异常指标J波、ST段抬高、QTd、JTd延长均可作为AMI患者恶性室性心律失常的预测指标.     

不同剂量卡维地洛对急性心肌梗死患者QT、JT离散度及心率变异性的影响

目的 研究不同剂量卡维地洛对急性心肌梗死患者QT、JT离散度及心率变异性的影响.方法 80例急性心肌梗死患者纳入研究,接受为期3个月的治疗.根据卡维地洛用量将患者随机分均为小剂量组（3.125 mg～6.25 mg,每天2次）和大剂量组（12.5 mg～25 mg,每天3次）.治疗前后所有患者均接受长程心电图检查.记录QT、JT离散度及心率变异性的时域、频域指标.所有患者随访半年.结果经过3个月的治疗,两组QT、JT离散度、心率变异性时域及频域指标较治疗前明显改善,大剂量组更为明显（P〈0.05）.两组半年内不良心血管事件发生率无统计学意义（P〉0.05）.结论与小剂量相比,大剂量卡维地洛能进一步减小急性心肌梗死患者QT、JT离散度,提高慢性心率变异性,但不降低半年内不良心血管事件.     

The Effect of Left Ventricular Function on QT Dispersion in Postmyocardial Infarction Patients with Previous Ventricular Tachyarrhythmias

Objectives: To determine if the presence of left ventricular dysfunction increases the QT and QT_c dispersion in postmyocardial infarction patients with ventricular tachyarrhythmias and to determine if left ventricular infarct location is associated with differences in QT and QT_c dispersion. Methods: The data was gathered from a retrospective electrophysiology (EP) database. All postinfarction patients (n = 87) with a past medical history of left ventricular myocardial infarction and ventricular tachyarrhythmia at baseline without bundle branch block or other intraventricular conduction abnormality were included. Patients were separated into those with an LVEF < 40% or < 40%. For secondary analysis, patients were separated into groups based on the location of the infarction. The QT and R‐R intervals were determined from each lead of a 12‐lead electrocardiogram (ECG) taken during the baseline EP study. The shortest QT and QT_c intervals were subtracted from the longest intervals on the 12‐lead ECG to give the QT and QT_c dispersions. Results: The QT and QT_c interval dispersions were significantly greater among patients with an LVEF < 40% than among those with an LVEF < 40% (57.3 ± 28.2 vs 47.4 ± 17.7, P = 0.05; 64.5 ± 32.1 vs 48.8 ± 18.2. P = 0.005, respectively). No differences in QT or QT_c dispersion were noted between patients with anterior or inferior myocardial infarctions. Conclusions: A higher QT dispersion can be predicted in patients with left ventricular dysfunction, but the location of the myocardial infarction does not predict the QT dispersion.     

正常人不同导联,电压及性别JT,JTc间期和JTc／QTc值的比较分析

对２１０例正常人Ⅱ和Ｖ３导联１ｍＶ（１ｍＶ＝１０ｍｍ）、２ｍＶ及性别之间进行ＪＴ、ＪＴ间期和ＪＴｃ／ＱＴｃ值的比较分析。结果显示：不同电压间、不同电压间、不同导联间及男女性别间ＪＴ、ＪＴｃ间期及ＪＴｃ／ＱＴｃ值的差异有显著性。     

The semipermeability of simple spherical virus capsids

Hydrogen-ion titration curves are reported for tomato bushy stunt virus, two strains of cowpea chlorotic mottle virus, and turnip crinkle virus, with particular attention to the hysteresis loops associated with the swelling and contraction of virions. There appears to be an archetypal shape of hysteresis loops, which is shared by viruses in several groups, suggestive of many intermediate states in the swelling of any one particle. In contrast, eggplant mosaic virus behaves as if its protein capsid is impermeable to small ions in mild conditions; its cation-binding sites were revealed by treatment with high concentrations of salt or urea, or at raised temperatures. Putting these observations together with the fact that a spherical virus capsid is a closed, holey, charged surface leads to a theory of titration hysteresis: its key feature is that the protein capsids of simple viruses are inherently semipermeable, with many of the ion-handling properties usually attributed only to complex lipid membranes.