Effect of Propranolol on Ventricular Rate During Atrial Fibrillation in the Wolff-Parkinson-White Syndrome

Atrial fibrillation was induced during an electrophysiology study in 10 patients with the Wolff-Parkinson-White (WPW) syndrome, after determination of baseline properties of the accessory atrioventricular (AV) connection; intravenous propranolol (0.2 mg/kg) was then administered. Atrial fibrillation terminated during the drug infusion in three patients, allowing determination of propranolol's effects on conduction and refractoriness during sinus rhythm, before atrial fibrillation was reinduced. In these three patients propranolol had no effect on refractoriness or conduction properties of the accessory AV connection during sinus rhythm. The mean ventricular rate during atrial fibrillation was slowed by 15–56 beats/min in six patients, had no effect on the mean rate in three patients, and markedly increased the ventricular rate (203 to 267 beats/min) in one patient. In this patient, 54% of QRS complexes during atrial fibrillation were narrow, compared to 0–25% in the other patients. Propranolol reduced the percentage of QRS complexes that were narrow from 13 ± 16% to 1 ± 2% (mean ± standard deviation, p < 0.05). We conclude that propranolol may slow the ventricular rate during atrial fibrillation in some patients with the WPW syndrome, probably by blockcing the effects of adrenergic activation. However, propranolol should not be used in patients with the WPW syndrome who have atrial fibrillation, if most QRS complexes during atrial fibrillation are preexcited. When a large percentage of QHS complexes are narrow, propranolol may increase the ventricular rate, probably by eliminating concealed retrograde conduction in the accessory AV connection.     

Use of CO2 to move structures as an aid to percutaneous procedures

By injecting small amounts of CO2 through a needle, one can move bowel or bladder from the intended path of instruments during interventional procedures. The technique worked well in six of seven cases in the pelvis and retroperitoneum; it was not effective in the mediastinum or midabdomen (n = 6).     

Recombination aneusomy of chromosome 5 associated with multiple severe congenital malformations

A male infant is described in whom congenital anomalies were recognized prenatally by ultrasound examination. The infant was delivered following spontaneous labor and died approximately 15 min after birth. An autopsy revealed major anomalies in the central nervous system (holoprosencephaly with premaxillary agenesis), the gastrointestinal system (esophageal atresia) and the heart (tetralogy of Fallot). Chromosomal studies revealed recombinant chromosome 5 [46,XY, rec(5), dup q, inv(5)(p15q32)], resulting in partial trisomy 5q and partial monosomy 5p. Cytogenetic investigation of the family revealed a pericentric inversion of chromosome 5 in the father and paternal grandmother, 46,XY (and XX, respectively,) inv(5)(p15q32). The congenital anomalies in this infant are more extensive and severe than previously reported in cases of recombination aneusomy involving chromosome 5.     

Massive Cerebral Edema Associated with Fulminant Hepatic Failure in Acetaminophen Overdose

Cerebral edema may complicate the course of fulminant hepatic failure. Response to conventional therapy has been disappointing. We present a patient with fatal acetaminophen-induced fulminant hepatic failure, with signs and symptoms of cerebral edema, unresponsive to conventional medical therapy. Cranial decompression was carried out. A justification of the need for further evaluation of cranial decompression in such patients is presented.     

The Relationship Between Sinoatrial Conduction Time and Sinus Cycle Length Revisited

In 1974 we reported an inverse relationship between sinoatrial conduction time (SACT) and sinus cycle length (SCL) during sinus arrhythmia utilizing the indirect atrial premature stimulation technique for estimating SACT, However, this behavior seemed anomalous try analogy with the AV node. Subsequent to 1974, methodological considerations about and limitations of the indirect techniques for estimating SACT became apparent, making us question our former impression. When the capability to directly record sinus node electrograms was developed and established in the 1980s, we had the means to reevaluate the SACT/SCL relationship. This report presents our findings in 40 patients: the SACT/SCL relationship is direct, not inverse. Moreover, we also show that during the phasic fluctuations of sinus arrhythmia, the P-P alterations are initiated more frequently by changes in sinoatrial conduction time than by changes in sinus cycle length.     

全膝关节置换术后的骨溶解：胫骨盘表面的修饰及聚乙烯衬垫灭菌方法对其的影响术 后5至10年的报告

背景：从关节和胫骨假体聚乙烯衬垫后表面转移磨损碎屑，是全膝关节置换术后假体周围骨溶解的主要原因。全膝人工关节假体设计随时问而发生变化，例如对胫骨盘近端表面的粗糙度和聚乙烯衬垫的灭菌方法。我们假设胫骨盘表面抛光和采用空气中γ射线照射之外的其他方法对衬垫灭菌，可降低骨溶解的发生率。方法：从1987年至1998年，我们采用后十字韧带保留型的解剖型组配式全膝人工关节假体系列。对300名患者施行365例全膝关节置换术。术后5至10年，对这些患者的膝关节摄正、侧位X线片。由两位关节置换专家对X线片上的骨溶解状况进行单独评定（骨溶解的界定标准为假体周围存在边缘清晰的非线性松质骨丢失区）。结果：在粗糙表面的胫骨盘的242例膝关节中，使用空气中γ射线照射灭菌的衬垫固定，有34％（82例）骨溶解阳性。用惰性气体中γ射线照射或没有照射的衬垫与抛光表面连接的98例膝关节中，有9％（9例）骨溶解阳性。骨溶解与六项因素相关，这些因素为：一项与患者（男性）相关、一项与胫骨盘（近端表面抛光）相关、三项与聚乙烯衬垫（加工的原材料、灭菌方法及存放时间）相关及一项与手术技术（股骨假体与胫骨假体间的过伸）相关。结论：在这类假体设计中，胫骨盘近端表面采用抛光及衬垫采用更为先进的灭菌方法（不用空气中γ射线照射灭菌）能显著减少骨溶解的发生率，但不能避免骨溶解。     

冠状动脉斑块与心肌缺血

目的采用心脏MR(CMR)前瞻性研究冠状动脉斑块对心肌缺血的预测价值。方法 52例行冠状动脉造影(CA)后评定为可疑冠心病(CAD)的病人进行了CMR和