Optimized multi-shot imaging inspection design.

The inspection of complex-shaped components, such as those enabled by additive manufacturing, is a major challenge in industrial quality assurance. A frequently adopted approach to volumetric non-destructive evaluation is X-ray computed tomography, but this has major drawbacks. Two-dimensional radiography can overcome some of these problems, but does not generally provide an inspection that is as capable. Moreover, designing a detailed inspection for a complex-shaped component is a labour-intensive task, requiring significant expert input. In response, a computational framework for optimizing the data acquisition for an image-based inspection modality has been devised. The initial objective is to advance the capabilities of radiography, but the algorithm is, in principle, also applicable to alternative types of imaging. The algorithm exploits available prior information about the inspection and simulations of the inspection modality to allow the determination of the optimal inspection configuration, including specifically component poses with respect to the imaging system. As an intermediate output, spatial maps of inspection performance are computed, for understanding spatially varying limits of detection. Key areas of innovation concern the defect detectability evaluation for arbitrarily complex indications and the creation of an application-specific optimization algorithm. Initial trials of the algorithm are presented, with good results.

Influence of atrial flutter ablation on right to left inter-atrial conduction.

AIMS: Ablation of the atrial isthmus between the tricuspid annulus and the inferior vena cava changes P-wave morphology during low lateral right atrial pacing. For better understanding of the mechanism of this alteration, the sequence of activation of the inter-atrial septum and the left atrium were compared before and after ablation of the isthmus between the inferior vena cava and the tricuspid annulus. METHODS AND RESULTS: In 13 patients, left atrial mapping was performed using a duodecapolar electrode catheter advanced to the far distal coronary sinus. The inter-atrial septum was mapped using a right atrial duodecapolar electrode catheter. Conduction times were measured during low lateral right atrial pacing from the pacing artefact and during sinus rhythm from the earliest right atrial electrogram to every intra-cardiac electrogram before and after the ablation. During low lateral right atrial pacing, isthmus ablation resulted in a significant delay in every left atrial lead. Changes were maximal at the posterior aspect of the left atrium and minimal at its anterior aspect. No significant change was discernible on the inter-atrial septum. During sinus rhythm, atrial activations remained unchanged. CONCLUSION: Electrocardiographic changes of P-wave morphology result from alteration in the sequence of left atrial activation rather than that of the inter-atrial septum.

Symptomatic pericardial disease associated with patch electrodes of the automatic implantable cardioverter defibrillator: an underestimated complication?

Constrictive pericarditis can be associated with ICD patch electrodes. During a mean follow-up of 24 months, in a population of 35 patients who received ICDs with a patch electrodes configuration, we identified three patients with clinical and hemodynamic signs compatible with this event. Patient 1, a 35-year-old male, underwent implantation of an ICD because of a primary electrical disease complicated by cardiac arrest. Fourteen months later he complained of exertional dyspnea without any signs of heart failure. Right heart catheterization showed high filling pressures and diastolic dip and plateau in pressure curves. Thoracotomy and pericardial exploration were performed. Three months after removal of the patches and insertion of an endocardial lead system, the patient had normal respiration. Patients 2 and 3, who suffered from coronary heart disease without heart failure, exhibited a hemodynamic profile suggestive of constrictive pericarditis: in one patient, 10 months after ICD implantation, associated with right heart failure; and in the other, 18 months after ICD implantation with left heart failure. Patch electrodes were removed in these two patients and replaced by endocardial lead electrodes with subsequent clinical improvement. It is concluded that constrictive pericarditis related to epicardial patch is not an uncommon occurrence during ICD therapy and should be considered in patients who show clinical signs of cardiac decompensation.

[Predictive factors of induction of ventricular arrhythmia under amiodarone]. / Facteurs prédictifs du déclenchement d'une arythmie ventriculaire sous amiodarone.

A good result of electrophysiological investigations under amiodarone therapy distinguishes a low risk group of patients with malignant ventricular arrhythmias. The authors set out to determine the factors predictive of this response in order to identify patients better protected by amiodarone at an earlier stage. Fourty-five patients with an average age of 56 years, were referred for evaluation of severe ventricular arrhythmias, monomorphic ventricular tachycardia being inducible during electrophysiological investigation in all cases before treatment. Amiodarone was prescribed orally at degressive doses. A control electrophysiological study was performed 4 to 6 weeks later. Eighteen patients (40%) were considered to be responders (absence of inducible ventricular arrhythmia or inducible non-sustained tachycardia or tachycardia with a cycle length increased by over 100 ms with respect to the base-line study). The other 27 patients were considered to be non-responders. No clinical or paraclinical parameter was found to distinguish responders from non-responders. The authors conclude that the data obtained before control electrophysiological investigation under amiodarone does not allow prediction of the response to this drug. The search for early prognosis of the efficacy of amiodarone in preventing ventricular arrhythmias therefore requires electrophysiological investigation after impregnation.

[Sustained ventricular tachycardia: an evaluation of long-term prognosis]. / Tachycardie ventriculaire soutenue: une évaluation du pronostic à long terme.

The authors analysed the clinical and paraclinical variables of 116 patients admitted to the Hôpital Cardiologique de Lyon between 1986 and 1990 with sustained ventricular tachycardia without cardiocirculatory arrest in order to determine the long-term outcome and the prognostic factors of death and recurrence. The average age of the patients was 56 +/- 15 years (mean +/- SD) and 83% were men. The mean ejection fraction was 39 +/- 15%. Sixty-five had previous myocardial infarction (group I); 30 (group II) had dilated cardiomyopathy (n = 21), right ventricular dysplasia (n = 4), hypertrophic cardiomyopathy (n = 2), congenital (n = 2) or valvular (n = 1) heart disease. Group III comprised 21 patients with no apparent cardiac disease or isolated mitral valve prolapse. Brief syncope was reported in 12 cases. The paraclinical investigations showed 46 patients (66%) with at least two criteria of positivity for ventricular late potentials; Holter recording showed doublets or runs of VES in 46% of cases and sustained or non-sustained VT was induced during exercise testing in 16 patients (22%). Programmed ventricular stimulation triggered VT in 85%, 79% and 61% of patients in groups I, II and III respectively. The patients were treated with amiodarone in 65 cases, a betablocker in 25 cases, catheter ablation of the origin of the tachycardia in 12 cases, antiarrhythmic surgery in 6 cases, coronary bypass grafting in 5 cases (with an associated antiarrhythmic procedure in 3 cases). An automatic defibrillator was implanted in 9 patients. The average follow-up period was 32 months (range: 17 days to 65 months).(ABSTRACT TRUNCATED AT 250 WORDS)

[Radiofrequency ablation of intranodal tachycardia]. / Traitement par radiofréquence des tachycardies intranodales.

The first radical approach to the treatment of atrioventricular nodal reentrant tachycardia was surgical dissection of the perinodal region. This technique has been replaced by the delivery of radiofrequency energy by an ablation catheter to the region of the atrioventricular node. The aim of this report is to describe the authors' experience of atrioventricular nodal application of radiofrequency current. The study comprised 53 cases (32 women and 21 men, mean age 46 +/- 17 years) with frequent attacks of reciprocating tachycardia. Endocavitary electrophysiological investigation confirmed the intranodal reentrant mechanism. The region of application of the radiofrequency current was located radiologically and then the precise site determined by the recording of nodal electrical activity. The appearance of junctional rhythm during the procedure was also used as a means of identification of the zone of ablation. Dual conduction persisted after ablation in 35 patients. However, no episode of tachycardia could be induced after the procedure. The AH interval increased during application of radiofrequency current in 3 cases but this abnormality regressed in the 2 months following the procedure. Recurrences of nodal reentrant tachycardia were observed in 14 cases (26%), 24 hours to 2 months after ablation. The rate of recurrence was significantly higher in patients who did not have a junctional rhythm during application of the radiofrequency current (62% vs 4%, p < 0.05). The number of recurrences was also greater in the group of patients with persistence of slow intranodal conduction after the radiofrequency ablation (p < 0.04). A second session of radiofrequency ablation was undertaken in 14 patients and a third session was required for 2 of them.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiofrequency ablation of atrial flutter. Efficacy of an anatomically guided approach.

BACKGROUND: Previous reports have shown that radiofrequency ablation can terminate atrial flutter and prevent recurrences. However, different methods have been used, and the current experience remains limited. The objective of the present study was to determine the efficacy of radiofrequency ablation of atrial tissue in patients with atrial flutter using an anatomically guided approach. METHODS AND RESULTS: We treated 22 patients aged 30 to 73 years. Atrial flutter was recurrent for a mean of 5 years despite the administration of multiple antiarrhythmic drugs. Radiofrequency current was directed to the atrial isthmus between the inferior vena cava and the tricuspid ring, regardless of the morphology of local electrograms. Radiofrequency energy was applied during typical atrial flutter in 12 patients, atypical atrial flutter in 2 patients, and successively both forms in 8 patients. In 19 patients, atrial flutter abruptly terminated. In 3 patients, atrial flutter persisted despite 37, 48, and 25 applications, respectively. Atrial recordings demonstrated that atrial flutter termination occurred as a consequence of conduction block at the site of radiofrequency energy application, regardless of the type of atrial flutter. The number of applications before termination ranged from 1 to 82 (mean, 32). Atrial flutter could no longer be induced in every case. There were no complications. During a 13-month mean follow-up, atrial flutter recurred in only 2 of the 19 patients who had a successful ablation. Four patients experienced chronic atrial fibrillation, and 2 of them returned to sinus rhythm with antiarrhythmic therapy. CONCLUSIONS: Radiofrequency ablation of atrial flutter using anatomic guidance is feasible and effective. Further experience is needed to delineate its role as an alternative approach to the management of refractory atrial flutter.

[Long-term course after electric ablation of the bundle of His in the treatment of supraventricular tachycardia]. / Evolution à long terme après ablation électrique du faisceau de His dans le traitement des tachycardies supraventriculaires.

The authors report the long term results of His bundle ablation for supraventricular tachycardia in a series of 49 patients. This retrospective study was based on a patient population of 27 men and 22 women with an average age of 59 at the time of ablation, between 1984 and 1993. The indication for His bundle ablation was invalidating supraventricular tachycardia resistant to antiarrhythmic therapy in all cases. One group of patients (Group I, n = 31 patients) underwent high energy electrical shock and the second group (Group II, n = 18 patients) recruited after 1991, underwent radiofrequency catheter ablation. Complete atrioventricular block was obtained in the first group in 1 to 4 sessions whereas 17 patients of Group II were treated in a single session. During a follow-up period of an average of 40 months, 2 patients were lost to follow-up and 6 died, 3 of cardiac failure, 1 of a cerebrovascular accident, 1 of pulmonary carcinoma and 1 of unknown cause. In Group I, atrioventricular conduction persisted in 1 patient (primary failure) and reappeared in one other patient, but, in Group II, complete atrioventricular block persisted even in the patient in whom the interruption was not obtained with a single session of radiofrequency ablation. The patients were generally physically improved and satisfied not to have any palpitations. A decrease in exercise capacity estimated by the NYHA classification was observed in 38% of patients without apparent cardiac disease who developed dyspnea. On the other hand, 43% of patients with cardiac disease and in NYHA class > or = 2 were improved.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hemomediastinum caused by spontaneous rupture of the thoracic aorta]. / Hémomédiastin par rupture spontanée de l'isthme aortique.

The authors report the rare case of spontaneous rupture of the aortic isthmus in the absence of preexisting aortic aneurysm or dissection in a hypertensive woman presenting with chest pain and haemomediastinum. The history of trauma 30 years previously, could have been a predisposing factor. The diagnosis of this condition remains difficult and is often missed. The physiopathological, aetiological, clinical and diagnostic features are reviewed. Transoesophageal echocardiography showing an intraparietal haematoma confirmed the aortic origin of the haemomediastinum. Conventional angiography was of no value in the reported case because of the absence of rupture of continuity or of an intimal tear.

Pharmacokinetics of tolfenamic acid in the horse.

The pharmacokinetics of tolfenamic acid were studied in five ponies after an intravenous (iv) administration (2 mg/kg bodyweight [bwt]) and in four horses after an oral administration (30 mg/kg bwt) of tolfenamic acid. The plasma levels were determined by high pressure liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). For the iv administration, a three-compartment model was used to represent the plasma concentration-time curve of the drug. The elimination half-life of the compound was 6.1 +/- 1.5 h, the total body clearance was 72.4 +/- 16.7 ml/kg bwt/h and the steady-state volume of distribution 0.32 +/- 0.11 litres/kg bwt. For the oral administration, absorbtion was delayed with a mean lag-time to absorption of 32 +/- 28 mins. The peak plasma concentration 11.1 +/- 0.69 micrograms/ml was observed after a highly variable delay ranging from 1.9 to 6.5 h post administration. The terminal half-life (4.2 +/- 0.48 h) was very similar to that obtained after iv administration. Tolfenamic acid could not be detected in equine plasma with the described analytical methods more than 48 h after drug administration.

[Amoebic keratitis caused by Acanthamoeba sp. May HSV1 infection play a role?]. / Kératite amibienne à Acanthamoeba sp. L'infection par HSV1 aurait-elle un rôle?

Many cases of human keratitis with Acanthamoeba sp. have a pseudo-herpetic appearance. The authors therefore evaluated the importance of co-infection with this virus in the onset of amoebic cornean lesions. After herpetic and amoebic co-infection rabbits showed severe cornean lesions, the viral aspect of cornea received a specific treatment. The amoebic co-infection progressed unchecked with severe lesions until day 37 p.i., in which trophozoites and cysts were numerous. The possible favourising role of HSV1 and Acanthamoeba sp. co-infection may exist in humans, just as it certainly exists in the rabbit.

[Value of nu/nu mice in the production of experimental amoebic keratitis with Acanthamoeba]. / Intérêt de la souris nu/nu dans la réalisation de la kératite expérimentale à amibes libres du genre Acanthamoeba.

The intracorneal inoculation of nude mice with Acanthamoeba hatchetti amoebae induced a keratitis with disruption of corneal fibres, inflammatory response, secondary vascularization and amoebic trophozoites.

[Acanthamoeba keratitis. Epidemiologic and parasitologic study]. / Kératite amibienne á Acanthamoeba. Etude épidémiologique et parasitologique.

The amebic keratitis with Acanthamoeba are until now rare, but however increasing as their diagnosis is better, and the contact lens wearers more numerous. The authors present the clinical and parasitological features of cases they did diagnose since 1986. In the immunological sphere, the T4 lymphocytes were 20% less than the normal for the first patient, and the third one had a very low level of immunoglobulins A. In the evolution sphere, the first one did received a keratoplasty; the second one has been successfully treated with propamidine isethionate; for the third one, the treatment with propamidine isethionate was nonuseful and a keratoplasty which was finally performed did show off numerous amebic cysts. In the parasitologic sphere, Acanthamoeba polyphaga was isolated from the first case, Acanthamoeba quina from the second one and Acanthamoeba lugdunensis from the last one. These last two cases are the first which did permit to isolate these amoebae, morphologically near to the first species.

Immunochemical and biochemical characterization of gastrin/cholecystokinin-like peptides in Palaemon serratus (Crustacea Decapoda): intermolt variations.

Gastrin/cholecystokinin (G/CCK)-like peptides cross-reacting with an antiserum specific for the carboxyamide terminal pentapeptide of gastrin and CCK have been detected in the eyestalks and in the stomach of the prawn Palaemon serratus using immunocytochemical methods. In the eyestalks, immunoreactivity is present in the neuroendocrine cells, the X organ-sinus gland tractus and the neurohemal organ itself. This suggests, for the first time, the existence of a neuroendocrine secretion of G/CCK-like peptides. Hemolymph G/CCK level is about 18 pM. In the stomach, G/CCK-like material has been observed in epithelial cells in the cuticle and in the lumen. Molecular sieving of crude extracts of the medulla terminalis from the eyestalks, the stomach, and the hemolymph samples on a Sephadex G-50 filtration column exhibited a molecular heterogeneity of the G/CCK immunoreactive material. Large components were observed principally in the medulla terminalis and in the hemolymph, and smaller forms in the stomach. A fraction common for the three tissues had an apparent molecular weight of 2500 Da. That fraction was characterized further by HPLC and shown to be more hydrophobic than human G17 I. By radioimmunoassay relatively low levels were detected in all the aforementioned organs. Although the concentration of the G/CCK-like components varies during the intermolt cycle, this was the case mainly in the hemolymph and in the stomach. These observations suggest a possible role of G/CCK-like peptides in molting processes.