The Treatment of Refractory Anaemia of Chronic Renal Failure with Cobalt Chloride

Twelve anephric patients on maintenance haemodialysis receivedtreatment with oral enteric coated cobalt chloride 25 to 50mg daily. The change in haemoglobin concentration, and packedcell volume, are recorded and discussed with special referenceto possible toxicity and mechanism of action of cobalt. Six of eight patients who completed the first course with cobaltchloride 50 mg daily for 12 weeks showed a significant risein haemoglobin concentration of 26 to 70 per cent and a fallto near pre-therapeutic levels when cobalt was withdrawn. Evidenceof a response was present within two months of starting treatment.Four patients showed a diminution in their blood transfusionrequirements and three patients experienced a definite senseof increased well-being during treatment. One patient sufferedfrom side effects of the drug and failed to complete the studybecause of gastrointestinal disturbance. The improvement in haemoglobin concentration was reproduciblein four patients who were given second, and in one case thirdcourses with varying doses of cobalt over differing periodsof time. Serum cobalt levels tended to stabilize after two months continuoustreatment to the therapeutic range of 40–100 µgper 100 ml. A rapid fall in serum cobalt was seen on cessationof treatment. It is suggested that therapy with enteric coated cobalt chlorideat a dose of between 25 and 50 mg per day has a definite placein the treatment of the refractory anaemia of chronic renalfailure.     

Inadvertent Detection of 60-Hz Alternating Current by an Implantable Cardioverter Defibrillator

LEE, S.W., et al. : Inadvertent Detection of 60-Hz Alternating Current by an Implantable Cardioverter De-fibrillator. A patient with an ICD received therapies from his ICD while exercising in an indoor swimming pool. Interrogation of the ICD revealed inappropriate detection of 60-Hz alternating current artifact and delivery of ICD therapies.     

Percutaneous Retrieval of Dislodged Left Atrial Appendage Occlusion Devices through the Transseptal Approach

Percutaneous left atrial appendage (LAA) occlusion is a promising treatment option in patients with atrial fibrillation who have a high risk of embolic stroke and are not eligible for chronic oral anticoagulation therapy. This procedure, however, can induce several complications. Device embolization can result in a serious situation, requiring immediate and safe device removal. We report two cases in which dislodged LAA occlusion devices were flitting in the left atrium or entrapped in the mitral valve leaflets and were successfully retrieved through a transseptal approach without complications.     

椎管内髓外硬膜下毛细血管瘤临床及MRI特征

目的 探讨椎管内髓外硬膜下毛细血管瘤的临床及MRI特征。方法 回顾性分析5例经手术病理确诊的椎管内髓外硬膜下毛细血管瘤的临床资料及MRI表现。结果 临床表现:胸背痛伴双下肢麻木、无力4例,颈部疼痛伴双上肢疼痛1例。MRI示肿块均为单发,均位于椎管内硬脊膜下脊髓背侧,胸段4例,颈段1例;T1WI呈等(4例)或低信号(1例),T2WI呈高信号,增强后多均匀强化(4例);病灶周围可见含铁血黄素沉积(1例)、脊膜尾征(1例)及肿块头侧可见引流血管(1例)。结论 椎管内髓外硬膜下毛细血管瘤好发于中年人,位于脊髓背侧。MRI特征表现为肿块周围引流血管、含铁血黄素沉积、脊膜尾征、显著均匀强化。     

Electrophysiologic Characteristics and Radiofrequency Catheter Ablation in Patients with Clockwise Atrial Flutter

RF Catheter Ablation of Clockwise Atrial Flutter. introduction: Although the mechanism and radiofrequency catheter ablation of counterclockwise (typical) atrial flutter have been studied extensively, information about the electrocardiographic and electropbysiologic characteristics and effects of radiofrequency ablation in patients with clockwise atrial flutter is limited. Methods and Results: Thirty consecutive patients with clinically documented paroxysmal clockwise atrial flutter were studied. Endocardial recordings and entrainment study using a “halo” catheter with 10 electrode pairs in the right atrium were performed. Radiofrequency energy was applied to the inferior vena cava-tricuspid annulus (IVC-TA) and/or coronary sinus ostium-tricuspid annulus (CSO-TA) isthmus to evaluate the effects of linear catheter ablation. Eighteen patients had both counterclockwise and clockwise atrial flutters, and 12 patients had only clockwise atrial flutter. Both forms of atrial flutter had similar flutter cycle lengths (232 ± 30 vs 226 ± 25 msec, P = 0.526) but reverse activation sequences. Right atrial pacing at a cycle length 20 msec shorter than the flutter cycle length from the CSO-TA isthmus, IVC-TA isthmus, and the area between the two isthmuses revealed concealed entrainment with stimulus-to-P wave intervals of 32 ± 19, 95 ± 14, and 50 ± 17 msec (P = 0.022) in the counterclockwise form, and 110 ± 12, 40 ± 20, and 60 ± 15 msec (P = 0.018) in the clockwise form. In clockwise atrial flutter, 20 patients with biphasic P waves in the inferior leads had the presumed exit site of slow conduction area located at the low posterolateral right atrium; 10 patients with positive P waves in the inferior leads had the presumed exit site located at the mid-high posterolateral right atrium. Among the 18 patients with both forms of atrial flutter, linear ablation lesions directed at the IVC-TA isthmus eliminated both forms of atrial flutter in 14 patients; in the remaining 4 patients. CSO-TA linear lesions eliminated the counterclockwise form and IVC-TA lesions eliminated the clockwise form. Among the 12 patients with the clockwise form only, CSO-TA linear lesions eliminated flutter in 2 and IVC-TA linear lesions eliminated flutter in 10 patients. Successful ablation was confirmed by creation of bidirectional conduction block in the IVC-TA and/or CSO-TA isthmus during pacing from the proximal coronary sinus and right posterolateral atrium sandwiching the linear lesions. During the follow-up period of 17 ± 8 months, 2 patients had recurrence of clockwise atrial flutter, 1 patient had new onset of atypical atrial flutter, and 2 patients had new onset of atrial fibrillation. Conclusions: Counterclockwise and clockwise atrial flutters may have overlapping slow conduction areas with different exit sites. Radiofrequency catheter ablation using the linear method directed at the IVC-TA and CSO-TA isthmuses was feasible and effective in treating both forms of atrial flutter.     

A prospective clinical study of isoniazid-rifampicin-pyrazinamide-induced liver injury in an area endemic for hepatitis B

In order to evaluate the incidence, predisposing factors and clinical course of antituberculous drug-induced liver injury in hepatitis B surface antigen (HBsAg)-positive carriers and non-carriers, in an area endemic for hepatitis B, we prospectively followed 240 patients (154 male, 86 female; mean age 40 years) who had received daily isoniazid, rifampicin, ethambutol and pyrazinamide for the treatment of pulmonary tuberculosis. Patients with heavy alcohol consumption, with pretreatment serum alanine aminotransferase (ALT) elevation and who had less than 3 months post-treatment follow-up were excluded from the study. Thirty-one (13%) patients were positive for serum HBsAg before treatment. Sixty-three (26%; 95% CI: 21–32%) patients developed antituberculous drug-induced liver injury. The incidence of drug-induced liver injury was significantly more frequent in patients > 35 years of age than in patients > 35 years of age (33 vs 17%; P < 0.05), but was not different between HBsAg carriers and non-carriers (29 vs 26%; P > 0.05). Using step-wise logistic regression analysis, patient age > 35 years was the only independent variable for predicting antituberculous drug-induced liver injury, while sex, acetylator phenotype, HBsAg carrier status and severity of tuberculosis were not. The peak serum ALT levels in antituberculous drug-induced liver injury were not significantly different between HBsAg carriers and non-carriers. Only one 61-year-old HBsAg carrier developed severe jaundice after 6 months antituberculous therapy; he subsequently died of hepatic failure. In conclusion, the incidence of antitubercuious drug-induced liver injury was significantly higher in patients > 35 years of age than in patients > 35 years of age, but was not different between HBsAg carriers and non-carriers. Mortality occurred in an aged HBsAg carrier superimposed with antituberculous drug-induced liver injury.     

The Effects of Isoproterenol on the Cardiac Conduction System

Dose-Dependent Effects of Isoproterenol. Introduction : Isoproterenol is used to assess and facilitate AV nodal conduction, and thus potentiate the induction of supraventricular arrhythmias. It is commonly administered in increasing doses until a predetermined decrease in sinus cycle length, usually 20% to 30%, occurs. This regimen may result in undesirable side effects. We have observed that effects of isoproterenol on the AV node may occur prior to achieving the target sinus cycle length. The purpose of this study was to determine whether the sinus and AV nodes have equal sensitivity to isoproterenol.
Methods and Results : Thirty-eight consecutive patients, who underwent electrophysiologic evaluation for a variety of indications, were given incremental doses of isoproterenol at 0.007, 0.014, 0.021, and 0.028 μ/g/kg per minute. Sinus cycle length and AV node function were assessed at baseline and after 5 minutes at each dose. The percent change from baseline in AV node function was compared with the change in sinus cycle length at each dose interval. Significantly greater decreases were observed in the anterograde and retrograde AV nodal Wenckebach cycle length (P < 0.0001) than in the sinus cycle length at the lowest isoproterenol dose (0.007 fig/kg per min). These differences were not apparent at higher doses. A sustained supraventricular tachycardia was inducible in 15 of 38 patients in the presence of isoproterenol, of which 40% occurred at the lowest dose.
Conclusions : The AV node is more sensitive than the sinus node to the effects of isoproterenol. Lower doses of isoproterenol than those commonly used may often facilitate the induction of a supraventricular tachyarrhythmia, thus reducing side effects.