A high-intensity highly coherent soft X-ray femtosecond laser seeded by a high harmonic beam.

Synchrotrons have for decades provided invaluable sources of soft X-rays, the application of which has led to significant progress in many areas of science and technology. But future applications of soft X-rays--in structural biology, for example--anticipate the need for pulses with much shorter duration (femtoseconds) and much higher energy (millijoules) than those delivered by synchrotrons. Soft X-ray free-electron lasers should fulfil these requirements but will be limited in number; the pressure on beamtime is therefore likely to be considerable. Laser-driven soft X-ray sources offer a comparatively inexpensive and widely available alternative, but have encountered practical bottlenecks in the quest for high intensities. Here we establish and characterize a soft X-ray laser chain that shows how these bottlenecks can in principle be overcome. By combining the high optical quality available from high-harmonic laser sources (as a seed beam) with a highly energetic soft X-ray laser plasma amplifier, we produce a tabletop soft X-ray femtosecond laser operating at 10 Hz and exhibiting full saturation, high energy, high coherence and full polarization. This technique should be readily applicable on all existing laser-driven soft X-ray facilities.

Superior sternoclavicular dislocation: A case report.

INTRODUCTION: Sternoclavicular dislocations are difficult to diagnose and often missed. Anterior dislocations are more common than posterior dislocations and typically have a low risk of complications. PRESENTATION OF CASE: We report the third case of post-traumatic superior sternoclavicular dislocation, which was successfully treated by functional treatment. DISCUSSION: The sternoclavicular joint is a diarthrodial joint with three degrees of freedom that is relatively immobile and incongruent. The treatment strategy for these injuries is based on two criteria: the possibility of vascular, nerve or tracheal compression such as in posterior dislocations, which is a surgical indication because of potential risk to life and function; the second indication is to improve esthetics, which is especially a concern with anterior dislocations. CONCLUSION: Superior sternoclavicular dislocation is a rare condition, with only three published cases up to now. Functional treatment can be used without complications.

Dynamics of a faceted nematic-smectic-B front in thin-sample directional solidification.

We present an experimental study of the directional-solidification patterns of a nematic-smectic-B front. The chosen system is C4H9-(C6H10)2CN (in short, CCH4) in 12 microm-thick samples, and in the planar configuration (director parallel to the plane of the sample). The nematic-smectic-B interface presents a facet in one direction-the direction parallel to the smectic layers--and is otherwise rough and devoid of forbidden directions. We measure the Mullins-Sekerka instability threshold and establish the morphology diagram of the system as a function of the solidification rate V and the angle straight theta(0) between the facet and the isotherms. We focus on the phenomena occurring immediately above the instability threshold when straight theta(0) is neither very small nor close to 90 degrees. Under these conditions, we observe drifting shallow cells and a type of solitary wave, called "faceton," which consists essentially of an isolated macroscopic facet traveling laterally at such a velocity that its growth rate with respect to the liquid is small. Facetons may propagate either in a stationary or an oscillatory way. The detailed study of their dynamics casts light on the microscopic growth mechanisms of the facets in this system.

Pattern stability and trijunction motion in eutectic solidification.

We demonstrate by both experiments and phase-field simulations that lamellar eutectic growth can be stable for a wide range of spacings below the point of minimum undercooling at low velocity, contrary to what is predicted by existing stability analyses. This overstabilization can be explained by relaxing Cahn's assumption that lamellae grow locally normal to the eutectic interface.

[Effect of adenosine triphosphoric acid (ATP) on accessory conduction bundles]. / Action de l'acide adénosine triphosphorique (ATP) sur les faisceaux accessoires de conduction.

The effects of an injection of 40 mg of ATP were studied in 48 subjects with an overt or latent preexcitation syndrome. The results showed that the slowing of anterograde or retrograde conduction by ATP was not specific for nodal conduction. This phenomenon was observed in conduction through Kent bundles with long refractory periods and the possibility of preexcitation due to the association of James and Mahaim fibres should also be considered.

[Danger of sinoatrial block and the use of antiarrhythmic agents in myocardial infarcts]. / Dangers du bloc sino-auriculaire et de l'emploi d'anti-arythmiques en cas d'infarctus du myocarde.

Nine cases of major ventricular arrhythmia (tachycardia (VT), fibrillation (VF), torsades de pointe) are reported in patients with sequellae of myocardial infarction but without residual angina or cardiac failure. --Six of these disturbances of excitability occurred after a bradycardia due to sino atrial block (SAB) which favoured the breakthrough of abnormal automatic foci. This form of the bradycardia-tachycardia syndrome was demonstrated by endocavitary electrophysiological exploration.. These were the only cases of major ventricular arrhythmia observed in a series of 88 SABs. Reputedly benign, they illustrate the potential gravity of a conduction defect in patients with sequellae of myocardial infarction. --Three other cases of abnormal ventricular excitability complicating the administration of 1 mg/kg of Ajmaline to test for paroxysmal block after myocardial infarction. These were the only cases of VT observed in a series of 800 Ajmaline tests. The three patients have had no further episodes of VT after 1 year's follow-up. On the other hand, in 43 Ajmaline tests without VT in patients with myocardial infarction, 6 cases of VT and 1 lethal VF were later observed. This demonstrates the lack of significance of episodes of VT during Ajmaline tests, the depressant action of the drug on intracardiac conduction favouring the initiation of reentry. In conclusion, a history of myocardial infarction exposes the patient to the risk of major ventricular arrhythmias in SAB, the detection of which should indicate pacemaker therapy from the first symptoms. The use of an intravenous antiarrhythmic agent should be avoided as it may aggravate arrhythmias. However, the arrhythmia is of no prognostic significance.

[Values of the effective anterograde refractory period of the bundle of His]. / Valeurs de la période réfractaire antérograde effective du faisceau de His.

The effective refractory period of the His bundle (ERP.H), the longest H1, H2 interval not followed by a V2 ventricular complex, was measured in 45 cases during the electrophysiological investigation of 500 Patients by premature atrial stimulation techniques. The patients were divided into two groups according to the result: Group I: 22 patients with syncope, a spontaneous HV interval greater than 60 ms, greater than 100 ms after Ajmaline or infrahisian block with atrial pacing at less than 150 bpm. Group II: 23 patients without these abnormalities. The ERP.H was significantly different (p less than 0,001) in the two groups with valves greater than 400 ms in Group I and less than 400 ms in Group II. It is suggested that in the absence of other electrophysiological abnormalities an ERP.H of 400 ms or over may be an indication for permanent pacing in patients with Stokes-Adams attacks. The finding of an ERP.H of over 400 ms is associated with severe infrahisian block. However, the ERP.H depends on the ERP of the AV node which must be shorter to calculate the refractory periods of the His bundle, and, above all, on the basal sinus cycle. The ERP.H decreases with shorter sinus cycles and cannot be calculated when the sinus cycle is less than 600 ms. Conversely, the critical value of 400 ms is not valid for cycles longer than 1000 ms as cycles of that length are associated with lengthening of the ERP.H. The regression of infrahisian block during programmed atrial pacing after Atropine does not seem to be a reliable method of distinguishing between physiological and pathological atrioventricular block.

[Hemodynamic and cartographic study of intravenous trinitrin in the acute stage of myocardial infarct]. / Etude hémodynamique et cartographique de la trinitrine intra-veineuse au stade aigu de l'infarctus du myocarde.

12 cases of acute myocardial infarction were prescribed intravenous trinitrin. Haemodynamically, the drug invariably affected the pre-load whether the haemodynamic state was normal (group I), or disturbed by left ventricular failure (group II). Myocardial function was only improved in cases with left ventricular failure. Mapping studies, performed to assess, at least theoretically, the degree of ischaemia, only showed a transient lowering of the ST elevation compared to a control group, and limitation of the ischaemic area around the myocardial necrosis could not be proved.

[French evaluation of cardiac stimulation]. / Bilan francais de la stimulation cardiaque.

A national enquiry into the problems related to definitive cardiac pacemakers, carried out in 1975, has yielded certain essential findings: the number of first-time implantations of pacemakers has been increasing by about 20% per annum; 92% of electrodes are currently implanted by an endocavitary technique, thoracotomy having now practically been abandoned; 90% of pacemakers implanted in 1975 were threshold models, inhibited by a QRS complex; the indications have become progressively wider, and are essentially related with the various forms of bradycardia, most frequently those due to atrio--ventricular block. In 1976, we have now reached a figure of about 200 new implantations of pacemakers per million inhabitants; those using lithium are increasingly superceding the mercury and isotope models.

[Systematic study of ventriculo-auricular conduction and its importance in the detection of aberrant conduction pathways]. / Etude systématique de la conduction ventriculo-auriculaire et son intérêt dans le dépistage des voies de conduction aberrantes.

Ventriculo-atrial conduction was studied by ventricular pacing in three groups of patients: 34 cases with the preexcitation syndrome on surface ECG, 35 cases with documented paroxysmal atrial tachycardia but with otherwise normal ECGs and 120 cases without either of these two conditions. This conduction time was unchanged up to pacing rates of over 160/min in 88 p. 100 cases with preexcitation and was thus a sign of a nodal short-circuit. This phenomenon was also observed in 85 p. 100 cases with isolated paroxysmal atrial tachycardia and in 20 p. 100 normal cases which suggests the presence of a latent accessory pathway in these patients.

[Results of the systematic application of ventricular stimulation methods]. / Résultats de l'application systématique des méthodes de stimulation ventriculaire.

This study was undertaken to test the validity of methods of evaluating ventricular tachycardia and in therapeutic surveillance. One hundred and thirty nine patients aged 16 to 84 years, with and without severe ventricular arrhythmias (ventricular tachycardia, VT, and fibrillation, VF) were divided into two groups after clinical, echocardiographic and 24 hour Holter investigations: Group I comprised 26 patients with a least one documented attack of VT or VF; Group II comprised 113 patients without these arrhythmias, who complained of dizziness, syncope, and/or their ECG showed a conduction defect, and so electrophysiological investigation was undertaken. A protocol of ventricular stimulation was undertaken in addition to the usual measurements of conduction times, comprising incremental ventricular stimulation from 100 to 200/min, single and paired extrastimulus in sinus rhythm and during ventricular pacing at rates of 100 and 150/min, the first extrastimulus being programmed 10 ms after the end of the ventricular effective refractory period. Excluding bundle to bundle reentry, the following results were obtained: In Group I: VT was triggered 16 times (61,5 p. 100), and in 4 of these cases VF occurred and required defibrillation. Ten patients had previous myocardial infarction; 5 patients had left ventricular dilatation. In 2 cases runs of 3 or 4 VES were recorded. No arrhythmia could be induced in 8 cases (30,8 p. 100); 5 of these patients had apparently normal hearts. In Group II: VT (greater than 5 VES) was triggered in 22 cases (19,5 p. 100) and in 4 cases this degenerated to VF requiring defibrillation. 11 patients had apparently normal hearts; 6 patients had left ventricular dilatation and 4 patients had previous myocardial infarction. 1 to 4 repetitive VES were observed in 67 cases (59,3 p. 100): the heart was judged to be normal in all patients except those with previous infarction. No correlation was established between the ability to induce VT and age, syncope, or ECG changes (especially bundle branch block). However, a correlation was found between the induction of VT and underlying cardiac disease and the method of induction of VT; in Group II, all episodes of VT were triggered by delivering paired ventricular extrastimuli on a background paced rhythm. These results show that repetitive ventricular responses can easily be triggered and that this has no pathological significance.(ABSTRACT TRUNCATED AT 400 WORDS)

[Cost of a coronary transluminal angioplasty compared with a single coronary bypass. Economic effects]. / Coût d'une angioplastie transluminale coronaire comparé à celui du pontage aorto-coronaire unique. Incidences économiques.

The authors discuss the financial incidence of transluminal coronary angioplasty (TCA) compared to isolated coronary bypass surgery (CBS). The study was limited to 1982 (76 cases of TCA) and compares two groups: successful TCA (17 consecutive cases: group I); isolated CBS (18 cases: group II). The following parameters were studied in each group: average length of hospital study, credits received from the Department of Social Security, hospital expenditure. Hospital expenditure was classified under 6 headings: personnel, material, investigations, drugs, hospital costs and administration costs. The results expressed as the mean per patient were: in group I: hospital stay, 10 days; Social Security reimbursement, 10 813 FF; hospital expenditure, 10 586 FF. In group II: hospital stay, 18 days (including 4 days in the ICU); Social Security reimbursement 46 656 FF; hospital expenditure, 28 955 FF. The hospital costs of personnel were relatively small (especially for TCA). The economies realised by reutilising catheters designed for single usage were significant: the use of guide wires, catheters and balloon catheters falls from 1.64, 1.9 and 0.1 per patient to 0.47, 0.53 and 0.05 respectively, a saving of 5 068 FF per TCA and 385 168 FF per year. Compared to costs in the United States (4 773 and 14 952 dollars) TCA and CBS is much cheaper in France.(ABSTRACT TRUNCATED AT 250 WORDS)

[Socio-professional rehabilitation after transluminal coronary angioplasty]. / Réinsertion socio-professionnelle aprés angioplastie transluminale coronaire.

Between April 1980 and October 1982, 109 patients underwent attempted transluminal coronary angioplasty (TCA) with a primary success rate of 71,6% (78 patients). Two patients died of complications of TCA and another one died suddenly 3 months after TCA. The socio-professional rehabilitation of the 106 survivors was studied by questionnaire to which 98 subjects (81 men, 17 women; average age 50,2 +/- 9,2 years) replied. Seventy seven patients were working before their coronary disease and 73 (62 men, 11 women; average age 46,4 +/- 9,1 years) replied to the questionnaire (95%). This constituted the study group, the socio-professional outcome or which was compared to that of 37 active patients who underwent single aorto-coronary bypass surgery during the same period. After TCA, 53 patients (73% returned to work, 48 as full time workers, after an average convalescent period of 4 months. Professional rehabilitation depended mainly on the initial result of TCA: 85% after primary success; 40% after failure (p less than 0,001); in the latter case, the rate of return to work improved if the patients had surgery (58%) rather than medical therapy (125%). Similarly, the average age of re-employed patients was lower (46,1 +/- 7,9 years, compared to 49,3 +/- 6,8 years, p less than 0,05). Finally, the patients returning to work usually claimed to be in good or very good health (72% compared to 30% p less than 001). After single aorto-coronary bypass, only 14 patients (38%) returned to work, 8 full-time, after an average 7 months' convalescence. The duration off work before surgery was related to the incidence of re-employment.(ABSTRACT TRUNCATED AT 250 WORDS)

[Significance of a supraventricular arrhythmia precipitated during an electrophysiological study]. / Signification d'un trouble du rythme supraventriculaire déclenché au cours d'une exploration endocavitaire.

The clinical history and 24 hour Holter monitoring of 749 patients without ECG appearances of ventricular preexcitation were compared with the results of electrophysiological investigations to determine whether supraventricular arrhythmias initiated during endocavitary electrophysiological investigations had any pathological significance. Endocavitary studies were undertaken to investigate symptoms of dizziness, syncope and/or conduction defects except in the group of paroxysmal junctional tachycardia (PJT) where the indication was investigation of a tachycardia (78 cases). In 544 patients (Group I) no arrhythmias were initiated. Thirty five patients (6.4%) had supraventricular tachycardia (SVT), atrial flutter (AFI), atrial tachycardia (PAT), atrial fibrillation (AF) or PJT. The anterograde Wenckebach point (AV) was over 200/min in 22 cases (4%). In 400 patients the Wenckebach point or the retrograde Mobitz II (VA') point was 170/min in 56 patients (14%). In 28 patients with spontaneous SVT in whom retrograde conduction was studied, 3 had a Wenckebach 200/min (17.7%) and 9 had a Wenckebach point (VA') greater than 170/min (32%). In 86 patients (Group II) paired atrial stimulation induced PJT. Seventy nine patients (91.8%) had PJT : AV was greater than 200/min in 19 cases (22%) and VA was greater than or equal to 170/min in 69 cases (80.2%). In 119 patients (Group III) a supraventricular tachycardia (other than PJT) was induced. Manipulation of the catheter in the atrium led to AF, AFI or PAT in 9 patients. Eight patients had SVT (80.8%), AV was greater than 200/min in one case (11.1%) and VA' greater than or equal to 170/min in 5 of the 7 cases in which it was measured (71.4%). Paired atrial stimulation induced atrial echos in 63 patients; 47 presented spontaneous SVT : AV was greater than 200/min in 7 cases (11.2%) and VA' greater than or equal to 170/min in 23 of the 60 patients investigated (38.3%). Paired atrial extrastimuli triggered AF or PAT in 18 cases : 16 cases (88.8%) had spontaneous SVT. AV was greater than 200/min in 3 cases (16.6%), VA' was greater than or equal to 170/min in 10 of the 17 cases investigated (58.8%) : 11 of these patients also had atrial echos. Fixed atrial stimulation (less than 200/min) triggered AF or AFI in 14 patients. Nine had spontaneous SVT (64.3%) : AV was greater than 200/min in 2 cases (14.2%) and VA' greater than or equal 170/min in 2 of the 10 cases studied (20%). Ventricular stimulation induced SVT in 15 patients, 14 of whom had SVT (92%).(ABSTRACT TRUNCATED AT 400 WORDS)

[Epidemiological profile of patients with myocardial infarction and normal coronary arteriography]. / Profil épidémiologique des sujets porteurs d'un infarctus avec coronarographie normale.

Of a total of 4,800 coronary arteriogrammes, 1,280 of which were carried out after myocardial infarction, 25 cases of proven infarction with normal coronary arteriography, confirmed by several "blind" interpretations, were retained. The interval between acute infarction and coronary arteriography was usually less than 6 months. The average age of the patients was 36.9 years, affecting more women than in classical coronary artery disease. The acute infarction was nearly always the first symptom. Cigarette consumption and hormonal factors is women were coronary risks factors of note. Ventricular sequellae were frequent, cardiac failure exceptional, exercise testing nearly always negative and occupational rehabilitation usually normal. It would seem that this affection is less serious than classical myocardial infarction due to atheroma probably because the non-infarcted myocardium is healthy, but the true prognosis of this type of coronary accident will only be revealed by long term studies. In the meantime the most useful investigations and the management of these patients are discussed.

[Left ventricular function in coronary disease. Gamma cineangiocardiography at equilibrium with right atrial pacing and nitroglycerine]. / Etude de la fonction ventriculaire gauche chez le coronarien. Gamma-cinéangiocardiographie à l'équilibre sous stimulation auriculaire droite et nitroglycérine.

25 patients (2 normal and 23 coronary artery disease) were studied by 99m Tc gated blood pool scans at rest, with right atrial pacing, right atrial pacing and nitroglycerine, and finally nitroglycerine alone. Total and regional ejection fractions were measured and the induced and reversible asynergy with right atrial pacing and nitroglycerine was also assessed.

[Mitral valve prolapse. Results of electrophysiological studies]. / Prolapsus de la valve mitrale. Résultats des études électrophysiologiques.

Classically, the frequency of latent left-sided Kent bundles and ventricular tachycardia (VT) is increased in mitral valve prolapse (MVP). To verify this hypothesis, 23 patients with clinical and echocardiographic (M mode and 2D) signs of MVP underwent electrophysiological studies for dizziness or syncope (12 cases) or palpitations (11 cases). In addition to the standard electrophysiological studies, analysis of sinoatrial and atrioventricular conduction, they underwent programmed ventricular pacing (St V2): coupled and then paired St V2 in sinus rhythm and during ventricular pacing (100-150/min) under basal conditions (15 patients), after injection of 2 mg Atropine (6 patients), and 10 micrograms of Isoproterenol (4 patients). These manoeuvres showed that symptoms of dizziness were due to increased vagal tone in 6 cases (associated with paroxysmal nodal tachycardia--PNT--in 3 cases), to sinoatrial block in 2 cases (associated with atrial tachycardia in 1 case), to suprahisian conduction defects in 3 cases (associated with atrial tachycardia in 1 case) and to VT in 1 case. Palpitations were due to VT in 1 case, atrial tachycardia in 1 case and PNT in 9 cases. Our analysis showed a high incidence of PNT (10 cases) with normal inter critical ECG. These arrhythmias were due to intranodal reentry in 7 cases (70%), to a latent left-sided Kent bundle in 2 cases and to a paraseptal Kent bundle in 1 case. These PNT were characterised by induction during exercise (6 cases) and by their association with flutter-type reentry (5 cases).(ABSTRACT TRUNCATED AT 250 WORDS)

[Vectorcardiography in inferior infarction associated with left bundle-branch block]. / Le vectocardiogramme dans l'infarctus inférieur associé au bloc de branche gauche.

The authors report a series of 13 patients, 8 men and 5 women, with an average age of 68 years (range 39 to 87 years) presenting with documented inferior infarction with anteroseptal extension in 2 cases. These patients developed LBBB (complete in 9 cases, incomplete in 4 cases). This complications occurred in the acute phase in 8 cases and 4 months to 9 years later (average 4,5 years) in the other 5 cases. The block was intermittent in 4 patients and became permanent in all cases. The diagnosis of inferior infarction with LBBB was made by vectorcardiography (VCG) in 5 out of the 13 patients (38,4 p. 100) on the criteria suggested by Starr. 3 of the 8 false negative results were directly related to the block which masked the ECG and VCG signs of inferior infarction. The VCG signs observed were an upwards displacement of the QRS loop with preservation of the superior orientation of the initial forces (5 cases). Atypical appearances of LBBB were observed in 2 cases with a posterior and right-sided shift of the efferent loop following the anterior and left-sided orientations of the initial forces. The sensitivity of the VCG and ECG is mediocre in inferior infarction with LBBB because the block may mask the electrical signs of inferior infarction. The specificity of the VCG could not be assessed because of the mode of selection of the patients and the small number of cases.

[Diagnostic value of methods of ventricular and auricular stimulation in the evaluation of tachycardia]. / Valeur diagnostique des méthodes de stimulation auriculaire et ventriculaire dans le bilan des tachycardies.

The diagnostic value of programmed pacing in the investigation of tachycardia (greater than 5 premature complexes) was studied in 155 patients admitted for evaluation of dizzy attacks and/or tachycardia by determining a relationship between the induction of tachycardia by endocavitary pacing and the presence of spontaneous attacks on ECG and/or 24 hour Holter monitoring. Right atrial and ventricular programmed pacing comprised: an extrastimulus during sinus rhythm (method I), during paced rhythm (method II), 2 extrastimuli during sinus rhythm (method III) and paced rhythm (method IV). The protocol was applied in 20 cases of spontaneous atrial tachycardia (AT) and 40 patients without tachycardia, and in 20 cases of spontaneous sustained ventricular tachycardia (VTS) (Group A), 15 cases of non-sustained ventricular tachycardia (VTNS) (Group B), 20 cases of ventricular doublets or triplets on Holter monitoring (Group C) and 40 patients without ventricular arrhythmias. The following results were obtained: At atrial level, method I was associated with a 75% sensitivity and a 62.5 p. 100 specificity when the triggering of atrial echos was considered. It was difficult to induce AT with methods I, II and III (sensitivity 15, 20 and 45 p. 100 - but they were very specific (greater than 90 p. 100). The induction of echos with methods II, III and IV was very sensitive but not specific and could not be retained as a pathological criterion. Using method IV, only the triggering of sustained AT could be considered to have a good specificity (90 p. 100), but sensitivity remained low (30 p. 100). At ventricular level, more aggressive methods were needed to induce an arrhythmia.(ABSTRACT TRUNCATED AT 250 WORDS)