Outcome after surgery for Maisonneuve fracture of the fibula

The aim of this study was to assess outcome in patients treated surgically for Maisonneuve fractures and to highlight factors associated with a suboptimal result. The authors present a review of 14 patients with Maisonneuve fractures. The mean age was 35.5 years. The most common injury mechanism was a twist incurred whilst participating in sport. The goal of treatment was the anatomic restoration of the ankle mortice with accurate renewal of fibular length. All patients had one or two suprasyndesmotic screws inserted percutaneously under fluoroscopic guidance. These were successfully removed under local anaesthesia in 13 cases (93%). Patients were reassessed clinically and evaluated both functionally and radiographically. Average follow-up was 25.3 months. Twelve patients (86%) had a satisfactory result. They returned to previous activity levels and had favourable Global Foot and Ankle (mean: 95.57) and Shoe Comfort (mean: 81.66) Raw Scores. Ankle range of motion and radiographs were normal. Two patients had an unsatisfactory result. Surgical intervention is recommended to maintain reduction of the fibula into the notch on the tibia, as shortening results in mandatory lateral talar displacement, predisposing to painful ankle arthrosis. The severity of the initial injury and co-morbid disease may adversely affect outcome.     

7天头低位卧床对人体心肺循环功能的影响

为了解模拟失重对心肺循环功能的影响采用ＸＸＨ－２０００型小循环心功能检测仪，观察了６名健康男性青年在头低位－６°卧床７ｄ中右胸电导纳容积波图的变化。卧床啵循环心功能参数的主要变化是：卧床初期Ｑ－ｊ、Ｑ－ｊ／ｊ－ｚ降低，ｈｚ、ｈｃ、ｈｃ／ｈｚ升高；２４ｈ后ｊ－ｚ缩短，Ｑ－ｊ／ｊ－ｚ升高。提示卧床初期出现肺动脉压升高、左心前负荷、右心前负荷和心肌收缩力增加，肺静脉充血；第３ｄ后有右心收缩功能下降。在头     

Heart Rate Variability in Passive Tilt Test: Comparative Evaluation of Autoregressive and FFT Spectral Analyses

The dynamic response of the autonomic nervous system during tilting is assessed by changes in the low (LF) and high frequency (HF) components of the RR series power spectral density (PSD). Although results of many studies are consistent, some doubts related to different methodologies remain. Specifically, the respective relevance of autoregressive (AR) and fast Fourier transform (FFT) methods is often questioned. Reat-to-beat RR series were recorded during 90° passive tilt in 18 healthy subfects (29 ± 5 years, eight females). FFT-based (50% overlap, Manning window) and AR-based (Levinson-Durbin algorithm) PSDs were calculated on the same RR intervals. Powers in very low frequency (VLF: < 0.04 Hz), LF (0.04–0.15 Hz), and HF (0.15–0.40 Hz) bands were calculated either by spectrum integration (FFT and AR_IN), by considering the highest AR component in each band (AR_HP), or by summation of all AR components (AR_AP). LF and HF raw powers (ms²) were normalized by total power (%P) and by total power after removal of the VLF component (nu). AR and FFT total powers were not different, regardless of body position. In supine condition, when compared to AR_HP and AR_AP. FFT underestimated VLF and overestimated LF, whereas in tilt position FFT overestimated HF and underestimated LF. However, supine/tilt trends were consistent in all methods showing a clear reduction of HF and a less marked increase of LF. Both normalization procedures provided a significant LF increase and further magnified the HF decrease. Results obtained with AR_IN were remarkably close to those obtained with FFT. In conclusion, significant differences between AR and FFT spectral analyses do exist, particularly in supine position. Nevertheless, dynamic trends provided by the two approaches are consistent. Normalization is necessary to evidence the LF increase during tilt.     

Diagnostic yield of external electrocardiographic loop recorders in patients with recurrent syncope and negative tilt table test

External electrocardiographic loop recording permits extended cardiac rhythm monitoring and ECG storage before and after device activation. The purpose of the study was to assess the diagnostic yield of external loop recorders in patients with more than two syncopal events within the last 6 months and a negative tilt table test. Twenty-four consecutive patients (51 +/- 14 years, male n = 9) were enrolled with 3 +/- 4 recurrent syncopal events within the last 6 months and no overt structural heart disease. The loop recorder CardioCall continuously records a two-channel ECG via skin electrodes. When activated, up to 4.5 minutes of the ECG preceding activation is stored. The time between tilt table testing and monitoring was 5 +/- 4 weeks. The average monitoring period covered 50 +/- 22 days. Recording was either unsuccessful or terminated prematurely in 5 patients. The reasons were skin irritation secondary to the electrodes in two patients, cable damage in one patient, and two patients inadvertently erased the stored data when replacing the batteries. Fourteen patients activated the loop recorder at least once. Symptoms leading to device activation were syncope (n = 1), dizziness (n = 11), feeling unwell (n = 7), palpitations (n = 5), headaches (n = 1), and chest pain (n = 1). The loop recorder documented sinus tachycardia during the syncopal event. Sinus tachycardia was also observed in 7 other patients, and atrial flutter in two patients. Eight patients had recurrent syncope with two patients experiencing syncope prior to the monitoring period, one syncope occurred in a patient who inadvertently erased the stored data, one event coincided with sinus tachycardia, and 4 (17%) patients had syncope during 15 +/- 10 months after termination of loop monitoring. The external loop recorder was not very useful for arrhythmia detection in patients with syncopal events, no overt heart disease, and a negative tilt table test because the cardiac rhythm was stored in only 1 of 8 (13%) patients with recurrent syncope. Reasons for the low diagnostic yield of external loop recorders were infrequent syncopal events after the baseline evaluation, with rare events during the limited monitoring period in particular, and premature termination or unsuccessful recording in 21% of patients.     

21天头低位-6°卧床对胃电图参数影响的观察

为研究模拟失重因素对胃运动功能的影响，头低位－６°卧床条件下，观察被试者胃电图参数的变化。１５名男性青年自愿被试者平躺于－６°床上，卧床２１ｄ。用便携式胃电图机测定进餐前后的胃电图，并分析功率谱。结果表明，头低位－６°卧床初期，被试者出现不同程度的腹胀、腹痛和食欲差的感觉；卧床后体重显著降低（Ｐ＜０．０１）。在卧床８ｄ以后胃电图胃动过缓（＜２．４ｃｐｍ）的百分数明显增加，胃动过缓节律百分数餐前与餐后有显著差异（Ｐ＜０．０５）；胃动过缓节律的动力学系数显著降低，随卧床时间延长，胃电胃动过缓节律增多，这提示２１ｄ模拟失重因素明显地影响胃运动功能。     

INCREASED PLASMA NORADRENALINE DURING LOW DOSE ADRENALINE INFUSION IN RESTING MAN AND DURING SYMPATHETIC STIMULATION

Both resting and stimulated (straight-leg raising and head-up tilt) levels of arterial and venous plasma noradrenaline were significantly higher during low-dose adrenaline infusion in five mild hypertensive and four normotensive patients with one adrenal. Repeat adrenaline infusions in the five hypertensive patients while measuring noradrenaline clearance (3H-noradrenaline constant infusion) achieved similar levels of plasma adrenaline, and similar increases in plasma noradrenaline, within five min of achieving target infusion rate. Increased plasma noradrenaline was not explained by reduced clearance. These results are consistent with the hypothesis that physiological concentrations of adrenaline are capable of facilitating noradrenaline release in man.     

Tilt Table Testing: Concepts and Limitations

Recurrent unexplained syncope is a common and often frustrating clinical problem. Over the last decade, bead upright tilt table testing bas emerged as an important diagnostic metbod far the identification of individuals whose syncope is likely to be neurocardiogenic in origin. At the same time, tilt table testing, by providing syncopal episodes in a controlled setting, has allowed for a much greater understanding of these disorders. This article reviews the concepts behind tilt table testing, as well as the uses and limitations of the evolving diagnostic modality.     

Bradycardia-Dependent Block and Fatigue Phenomenon of the His-Purkinje System Manifested During Upright Tilt

Atrioventricular (AV) block occurring in the His-Purkinje system may occur sporadically and can be difficult to document. In this article, we describe two patients with spontaneous episodes of AV block, in whom the use of upright tilt during electrophysiological testing led to a diagnosis of His-Purkinje disease. In both cases, testing in the supine position only uncovered mild or no abnormalities of infra-nodal conduction. In the first case, high grade block distal to the His occurred and the mechanism appeared to be bradycardia-dependent block. In this case, increased sympathetic tone due to upright tilt may have enhanced the slope of phase 4 depolarization in abnormal His-Purkinje cells, leading to block. In the second case, high grade block distal to the His was seen with upright tilt and the mechanism of block appeared to be fatigue phenomenon in the His-Purkinje system. These cases emphasize the elusive nature and varied mechanisms of His-Purkinje block and illustrate the utility of electrophysiological testing in the upright position in patients with suspected conduction system disease.     

Deep Breathing,Valsalva, and Tilt Table Tests in Diabetics with and without Symptoms of Autonomic Neuropathy

ABSTRACT. Autonomic neuropathy (AN) test results (Valsalva manoeuvre, deep breathing, and tilting) are frequently impaired in diabetics without symptoms of AN, particularly in those with peripheral neuropathy (PN). We have investigated 24 asymptomatic diabetics with PN, 17 diabetics with symptoms of AN and 24 healthy controls. The heart rate reactions to the three tests were impaired in both patient groups. The Valsalva manoeuvre could not distinguish between the patient groups. The heart rate reaction to deep breathing, estimated as the expiration/inspiration (E/I) ratio, was slightly more disturbed in patients with AN than in those with PN (1.04 vs. 1.09, p<0.05) but the frequency of abnormally low E/I ratios was high in both groups (76.5 vs. 54.2%, NS). The immediate heart rate reaction to tilting, estimated as the brake index, clearly separated the patient groups. An abnormally low brake index was shown in 82.3% of AN patients and in 33.3% of PN patients (p<0.01). The study shows that the deep breathing test is sensitive for AN but an impaired immediate heart rate reaction to tilting is more specific for symptomatic AN.