Marked Q-T prolongation due to encainide therapy

Summary Encainide is a type Ic antiarrhythmie agent. During encainide therapy, mild Q-T interval prolongation can be seen, usually associated with prolongation of the Q-R-S interval. The present case report describes an unusual and marked prolongation of the Q-T interval with no Q-R-S interval prolongation in a patient who was treated with encainide for atrioventricular nodal reentrant tachycardia. The drug metabolite profile in this patient's serum indicated an unusual elevation of the 3-methoxy-O-demethyl encainide metabolite, versus O-demethyl encainide. This elevated metabolite level suggests that 3-methoxy-O-demethyl encainide has a significant effect on prolongation of repolarization. An abnormal metabolism of encainide may be the underlying mechanism by which some patients would manifest an unusual prolongation of Q-T interval during encainide therapy.     

早搏联律间期缩短对血流动力学的影响

目的研究房性、室性早搏联律间期缩短与桡动脉图的关系,探讨早搏对血流动力学的影响。方法经心电图诊断为房性早搏48例及室性早搏51例,再应用心功能仪检查,通过信号处理技术对早搏桡动脉图形进行面积积分。结果①早搏桡动脉图积分面积提前率〉40%时最小,20%-40%时居中,〈20%时最大（P〈0.05）。②提前率相同情况下,左房与右房的早搏桡动脉图积分面积比较差异无统计学意义（P〉0.05）;左室与右室的早搏桡动脉图积分面积比较差异有统计学意义（P〈0.05）。③早搏时的桡动脉图积分面积最小,早搏前第一个窦性心搏居中,早搏后第一个窦性心搏最大（P〈0.05）。结论早搏对血流动力学的影响主要与早搏的联律间期长短有关,室性早搏还与其发生部位有关,早搏的代偿间歇,不能改善对血流动力学的影响。     

单发室性早搏中RT间期规律的分析

目的探讨室性早搏前后RT间期变化的规律。方法选取单发、有完全代偿间期的室性早搏心电图,测量室早及其前后相邻波群(简称室早前、室早、室早后)的RT间期,进行对比。对室早前心室舒张时间与室早RT间期变化的关系进行分析。结果RT间期由短到长的顺序为:室早<室早前<室早后。室早前心室舒张时间与室早RT间期无线性相关关系。结论室早时RT间期最短,室早后RT间期最长,这一变化规律与心室舒张时间无关。     

兔膝关节持续被动活动对前交叉韧带重建术后切口局部组织血氧饱和度的影响

目的 探讨膝关节持续被动活动（continuous passive motion, CPM）对兔前交叉韧带重建术后切口局部组织血氧饱和度的影响. 方法 20 只八月龄雄性新西兰大白兔右侧后肢膝关节行自体双股半腱肌腱移植重建前交叉韧带手术,术后随机分为2组：自由活动组（n＝10）和CPM组（n＝10）.自由活动组笼内自由活动;CPM组应用兔膝关节持续被动活动器运动.术后第2天,近红外光技术装置ODISseyTM 局部组织血氧监护仪测量每一来回（屈曲30°～110°）不同CPM速度（分别为2.35°/s、3.2°/s 、8°/s）时的切口局部组织血氧饱和度（tissue oxygen saturation ,StO2）变化,选择最好的CPM范围和速度.分别在术前和术后第2、4、6、8、10、14天观察膝关节CPM不同角度时切口局部组织StO2的变化. 结果 与自由活动组相比,3种速度的CPM在不同屈曲角度下均保持较高的StO2,且有显著性差异（P＜0.05）,不同CPM速度之间StO2有显著性差异（P＜0.05）.每一来回（屈曲30°～110°）运动速度为3.2°/s时保持最高的StO2.在术前和术后第2、4、6、8、10、14天等各时间点,膝关节屈曲30°、60°、90°、110°时StO2均无显著性差异（P＞0.05）,不同的时间点（术前和术后第2、4、6、8、10、14天）切口的StO2差别均有显著统计学意义（P＜0.05）.术后第2～4天最低,然后逐渐上升.术后第2周拆线后,切口愈合良好,没有感染、血肿和切口裂开. 结论 兔膝前交叉韧带重建术后第2天开始进行膝关节CPM（屈曲30°～110°）,可增加切口局部组织血氧饱和度,以3.2°/s的CPM速度最佳.     

Ventricular rate smoothing for atrial fibrillation: a quantitative comparison study.

AIMS: To quantitatively compare the ventricular rate-smoothing (VRS) effects of different ventricular pacing (VP) protocols for atrial fibrillation (AF). METHODS AND RESULTS: Using a recently developed open-source model that can simulate the ventricular response in AF and VP, the performance of fixed-rate pacing and four previously published VRS algorithms were assessed by the mean RR (mRR), the root mean square of successive RR differences (RMSSD), the percentage of ventricular senses (VS%), and the percentage of short RR intervals (sRR%). All pacing protocols cause rate-dependent reduction of RMSSD, VS%, and sRR% with or without shortening of mRR compared to spontaneous AF. Fixed-rate pacing was more sensitive to the intrinsic rate than the VRS algorithms. The performance was generally comparable between different VRS algorithms, although higher mRR and VS% can be achieved at the expense of larger RMSSD and sRR%. CONCLUSION: The effect of VP on ventricular rhythm in AF depends on both intrinsic rate and the aggressiveness of the pacing protocol. Adequate rate control is necessary for effective operation of the VRS algorithm. Choosing VRS algorithm should balance between the beneficial effects of rate regularization and the negative effects of increasing heart rate and percentage of VP.     

全髋关节翻修术中髋臼骨缺损的分类和重建研究进展

在髋关节翻修术中,髋臼骨缺损的治疗具有相当的挑战性。术前的计划,缺损的辨认和稳固的重建是成功翻修手术的基础。应用自体骨和同种异体骨移植填充骨缺损,目前使用特殊的重建方法行髋臼重建已取得了一定的疗效。临床上髋关节翻修手术越来越多,因此有必要针对髋臼骨缺损建立系统的诊断和治疗程序。本文就髋臼骨缺损的分类和重建进展做一综述。     

手部烧伤后重度虎口挛缩虎口重建术

自１９８９年２月～１９９５年３月，对２３例手部烧伤后重度虎口挛缩行瘢痕切除及虎口开大后，选用带旋髂浅血管蒂的腹股沟皮瓣移植重建虎口，术后均取得了满意效果。虎口挛缩的程度为０°～２５°。虎口开大后达８０°～９０°。虎口区瘢痕切除后皮肤缺损最小８ｃｍ×５ｃｍ，最大１２ｃｍ×６ｃｍ，平均１０ｃｍ×５ｃｍ。皮瓣切取面积最小１４ｃｍ×７ｃｍ，最大１８ｃｍ×８ｃｍ，平均１６ｃｍ×７ｃｍ。术后皮瓣断蒂时间为２～３周，２３例皮瓣均完全成活。对重度虎口挛缩应用带旋髂浅血管蒂的腹股沟皮瓣移植重建虎口是一种简单易行、成功率高的方法。因其具有供区部位隐蔽，皮肤质量好，不损伤肢体重要血管及可早期断蒂等优点，极易被患者接受。     

Sympathetic skin response and R–R interval variation in chronic uremic patients

Sympathetic skin response (SSR) and R–R interval variation (RRIV) were studied in 36 chronic, nondiabetic uremics to compare with their nerve conduction studies (NCS) and clinical dysautonomia. Abnormal SSR was noted in 5 (13.9%) patients, abnormal RRIV in 14 (38.9%), and abnormal NCS in 26 (72.2%). The patients were classified into three groups: group (GP) 1: “normal,” n = 21 (58.3%), normal RRIV and SSR; GP 2: “isolated parasympathetic dysfunction,” n = 10 (27.8%), abnormal RRIV and normal SSR; and GP 3: “sympathetic sudomotor dysfunction,” n = 5 (13.9%), abnormal SSR. A significant difference in age was found among the three groups (GP 3 > GP 2 > GP 1; P < 0.0001, ANOVA). After controlling the age factor, we still noted a tendency toward increasing NCS disturbances (distal latency and nerve conduction velocity of peroneal nerve; P < 0.05, multiple regression analysis) and frequencies of clinical autonomic symptoms (postural dizziness and impotence; P < 0.05, Mantel–Hanszel test) from GP 1 to GP 3. Patients with abnormal SSR (GP 3) displayed significantly higher frequencies of postural dizziness and impotence, indicating the relationship between an absence of SSR and clinical dysautonomia. © 1994 John Wiley & Sons, Inc.     

Effects of gender,age, and heart rate on QT intervals in children

The objective of this study was to determine if gender, age, and heart rate affect corrected QT intervals in children. Electrocardiograms were obtained from 781 healthy children 10–18 years of age. Corrected QT intervals were significantly (p < 0.0005) greater for girls than for boys in the entire population and for each age group over 14 years. The corrected QT interval varied inversely with age and directly with heart rate. Hence gender, age, and heart rate should be considered when diagnosing long QT syndrome.     

Sources of unwanted variability in measurement and description of skin surface topography

Background/aims: Quantitative measurement of skin roughness has proved to be a valuable tool in the efficacy-control of external applications, but it suffers from not yielding easily comparable results. The most important sources of inter-observer variability are high-pass filters used to separate roughness and waviness, and low-pass filters which result from the finite resolution of the instrument or from the finite sampling interval of digital measurement. In the present study, the effects of high-pass filters and sampling intervals on the roughness measured were investigated. Methods: Dynamically focusing optical profilometry was used to measure the surfaces of negative replicas of healthy human skin. High-pass cut-off wavelengths and sampling intervals were varied systematically. Results/conclusions: Virtually unbiased estimates for the roughness parameters K, Sk, R_q, and R_a can be obtained using sampling intervals of 40 or even 80 μm. Regarding these roughness parameters, it is far better to do more scans than to shorten the sampling interval. The roughness parameters R_z, R_p, R_t, R_pm, R_max, P_t, on the other hand are very sensitive to the influence of the sampling interval; to achieve satisfying estimates, the sampling interval should be no longer than 2 to 5 urn; as an important parameter’of the measurement, it is worthy of remark and should always be indicated. The way the mean square roughness R_q depends on the cut-off wavelength is not well described by the Sayles-Thomas-relation R_q～λ_c^0.5. If the power-spectrum |h*(v)|² approximates sufficiently to a power law, |h*(v)|²～v^δ, a better estimate is given by R_q～λ_c^γ with γ=-(δ+1)/2. In many cases, γ=1 or R_q～λ_c will suffice.