开通闭塞冠状动脉策略的全球性研究 GUSTO—Ⅱb（亚组研究）

病人资料 3 289例因急性冠脉综合征而接受溶栓治疗的患者,2274例接受t－PA治疗,1015例接受链激酶治疗。     

Ablation ektoper rechtsatrialer Tachykardien unter Verwendung eines 20-poligen Mapping-Katheters

INTRODUCTION : Ectopic atrial tachycardia (EAT) are frequently unresponsive to pharmacological antiarrhythmic therapy. Radiofrequency ablation seems to be a safe approach to treat those arrhythmias. In the present study we report our results of radiofrequency ablation of EAT with a new mapping system (Stablemapr, Medtronic). METHODS : Thirty consecutive patients with right atrial tachycardia were included in the study. In 15 patients (G1) the 20-polar Stablemapr was used for localization of the arrhythmia foci. Data were compared with a control group (G2, n=15), in which mapping was performed conventionally. The demographic characteristics and the distribution of the different cardiac diseases were comparable in both groups. In group 1 the identification of the EAT was facilitated by the placement of the 20-pole mapping catheter in the right atrium. In group 2 point by point measurements were performed to find the earliest local atrial activation compared to a reference electrode in the high right atrium (activation mapping), or foci were identified by analysis of the P-wave morphology during stimulation (pacemapping). RESULTS : It was possible to successfully ablate all atrial tachycardias. The distribution of the foci was similar in both groups (G1/G2): near to the superior (3/5) and inferior (1/0) caval vene ostium, on the free wall (3/3), at the coronary sinus ostium (3/3) and on the interatrial septum (5/4). The mean procedure (G1: 88+/-33 vs G2: 151+/-61 min; p= or <0.05) and fluoroscopic times (G1: 19+/-9 vs G2: 38+/-28 min; p= or <0.05) were significantly shorter in group 1. Moreover, the mean number of radiofrequency applications was reduced significantly by using the new mapping system (G1: 10+/-10 vs G2: 16+/-13; p= or <0.05). CONCLUSION : Radiofrequency ablation of EAT with right atrial focus can be performed safely and successfully using a 20-pole mapping catheter. The greatest advantages compared to conventional mapping and ablation strategies lies in the shortened investigation and fluoroscopic time.     

Paediatric use of intensive care

OBJECTIVES--To determine the number of children from a defined population who use intensive care facilities, to analyse bed occupancy data for those children, and to estimate the number of intensive care beds required to satisfy this demand throughout the year. DESIGN--Examination of admission data books from intensive care units within the four Birmingham health authorities and the neighbouring health authorities. RESULTS--Two hundred and ninety seven children resident within the four Birmingham health authorities used intensive care facilities in a calendar year. One hundred and forty one (47%) of these were admitted for specialist paediatric services. Of the remaining 156, 106 (68%) were cared for in adult intensive care units, 46 (29%) in a paediatric intensive care unit and four (3%) in a special care baby unit. Use of intensive care varied from none to 11 patients each day, and was lowest in the summer and highest during the winter months. During periods of peak demand, one in 19,000 (5.3/100,000) children were using intensive care facilities. CONCLUSIONS--These data provide a population based minimum need for paediatric intensive care beds. They are higher than previous estimates and do not include provision for children from outside Birmingham, or for those denied intensive care due to bed shortages. These factors and the marked seasonal variation in demand need to be considered when planning intensive care services for children if bed shortages are to be avoided.     

Decreased deformability of erythrocytes from smokers

The deformability of erythrocytes from smoking and non-smoking human subjects was examined by filtration through 3-mu pores and capillary viscometry of cell suspensions. In both cases, small but significant differences were found between the two groups that are consistent with a reduction in the surface area-to-volume ratio and/or a diminished membrane flexibility in erythrocyte from smokers. Additional evidence suggests that these findings represent a chronic rather than an acute effect of smoking on erythrocyte deformability.     

Helicobacter pylori infection, vitamin B12 and homocysteine. A review

It has been suggested that there is an association between Helicobacter pylori infection, reduced cobalamin absorption and cobalamin status and, consequently, elevated homocysteine levels. This would offer an explanation why H. pylori infection is associated with coronary heart disease. To date, more than 25 studies have been published that either deal with H. pylori infection and homocysteine, H. pylori infection and cobalamin status, or both. The design of these studies differs widely in terms of definition of H. pylori status, measuring cobalamin status, selection of study cohorts and geographical study areas. Therefore, results are fairly inconclusive at present and do not suggest a major role of H. pylori infection in the development of cobalamin deficiency and elevated homocysteine levels.     

Voltage-dependent Ca influx into identified leech neurones

We determined the relationships between the intracellular free Ca²⁺ concentration ([Ca²⁺]_i) and the membrane potential (E_m) of six different neurones in the leech central nervous system: Retzius, 50 (Leydig), AP, AE, P, and N neurones. The [Ca²⁺]_i was monitored by using iontophoretically injected fura-2. The membrane depolarization evoked by raising the extracellular K⁺ concentration ([K⁺]_o) up to 89 mM caused a persistent increase in [Ca²⁺]_i, which was abolished in Ca²⁺-free solution indicating that it was due to Ca²⁺ influx. The threshold membrane potential that must be reached in the different types of neurones to induce a [Ca²⁺]_i increase ranged between −40 and −25 mV. The different threshold potentials as well as differences in the relationships between [Ca²⁺]_i and E_m were partly due to the cell-specific generation of action potentials. In Na⁺-free solution, the action potentials were suppressed and the [Ca²⁺]_i/E_m relationships were similar. The K⁺-induced [Ca²⁺]_i increase was inhibited by the polyvalent cations Co²⁺, Ni²⁺, Mn²⁺, Cd²⁺, and La³⁺, as well as by the cyclic alcohol menthol. Neither the polyvalent cations nor menthol had a significant effect on the K⁺-induced membrane depolarization. Our results suggest that different leech neurones possess voltage-dependent Ca²⁺ channels with similar properties.     

Arch width development in Class II patients treated with the Fr?nkel appliance

This article compares the arch development in growing Class II patients after Fr?nkel therapy with arch development in a similar group of untreated Class II subjects. Sixty treated and forty-seven untreated persons were compared for a 2- to 4-year period. Expansion of the maxillary and mandibular dental arches occurred to a much greater extent in patients undergoing Fr?nkel treatment than in the control subjects. The expansion was not limited to a particular region of the dental arch in the treated cases, although the largest expansion values were recorded in the premolar and molar regions. Lesser values were recorded in the canine region.     

Femoral artery compression device for outpatient angiography

To avoid late bleeding from the femoral artery puncture site after outpatient femoral angiography, a compression device was designed to exert continuous pressure over the groin, even when the patient is upright. It has been successfully used in more than 2,000 arterial catheter procedures. The device can also help prevent bleeding in patients who are at increased risk because of hypertension or anticoagulant therapy.