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Atrial fibrillation is a daily cardiological problem which poses three types of questions, which, though old, are only partially mastered: anticoagulation, reduction and prevention of recurrence. It is a potent source of embolism. The risk is the greatest in patients with rheumatic valvular disease when the fibrillation is recent and when underlying cardiac disease is uncompensated. Long term anticoagulation is mandatory when the cause is rheumatic heart disease. In other pathologies, though anticoagulation has not been shown to reduce mortality, it significantly reduces the number of cerebrovascular accidents, including in the elderly and with low-dose vitamin K antagonist drugs. The efficacy of anticoagulation in preventing arterial embolism has not been established. Reduction of atrial fibrillation is not essential if the arrhythmia is well tolerated, chronic, especially in elderly patients and when several recurrences have occurred despite preventive therapy. In other cases, medical reduction is to be preferred to cardioversion if the fibrillation is recent and well tolerated. Of the oral and injectable preparations, amiodarone seems to be the drug with best benefit/risk ratio. Prevention of recurrence of fibrillation is unnecessary for many after a first episode, especially when idiopathic. In other cases, there are many available drugs but results are uncertain except in those observed in atrial fibrillation related to the autonomic nervous system. Strictly controlled and statistically exploitable studies show comparable efficacy of quinine and other Class I drugs. Beta-blockers are not very useful and the excellent long term results with amiodarone require confirmation.(ABSTRACT TRUNCATED AT 250 WORDS)

One of the hazards of high frequency electrical interference (electrocautery) with cardiac pacing is thought to be related to an increase in the threshold values leading to loss of pacing. This hypothesis was examined in an experimental study performed on 5 dogs. A pacing catheter was introduced via the right jugular vein and positioned at the apex of the right ventricle and connected successively to several stimulators implanted in a latero-cervical subcutaneous pocket. A Bovie 400 CT generator was used to deliver a high frequency 1.75 MHz current between a probe applied near to the pacemaker pocket and an electrode placed under the right leg. One or two 5 second bursts were applied for each make of pacemaker, making a total of 3 to 6 applications per animal. A detecting circuit enabled the measurement of the currents in the catheter during the application. The thresholds of pacing were measured before and after each manipulation for several pacing impulse durations. At the maximal output of the generator, the highest recorded current was 117 mA (modulated) and 141 mA (unmodulated). The thresholds of stimulation did not change significantly and the pacing catheter impedance was also stable. This study suggests that high frequency current does not modify the threshold of stimulation in cardiac pacemaker patients. The loss of pacing sometimes observed after the use of electrocautery is probably related to pacemaker dysfunction.

The aim in treating chronic atrial fibrillation, is not limited to simply achieving immediate regularization. What matters, is sustaining the sinus rhythm. The various methods of regularization, using either medical procedures or cardioversion, involve constraints and risks. Investigation of the relapse predicting factor is of great value in evaluating the benefit/risk ratio. For regularization, the absence ultrasound signs of heart disease, an undilated left atrium, recent atrial fibrillation and all forms of heart disease which are curable, albeit surgically, are indicative of success. With regard to prophylaxis, relapses occur more frequently in cases involving mitral valve disease, long-standing atrial fibrillation or a dilated left atrium.

The diffusion of ofloxacin in infected and healthy human and rabbit eyes was investigated. In the human study, cataract surgery patients were given intravenous ofloxacin either as a single 200 or 400 mg dose or as two 400 mg infusions 12 hours apart. Samples of aqueous humor and plasma were collected between 1 and 12 hours after the end of the infusion. Levels in the anterior chamber increased with the dose; peak levels, which occurred after three hours, were 0.33 mg/l after 200 mg and 1.24 mg/l after two 200 mg doses given 12 hours apart. In the rabbit study, 16 hours after experimental infection of the left eye by injection of S. epidermidis into the vitreous, animals were given an intraperitoneal injection of 20 or 50 mg/kg ofloxacin. Dosages in the various ocular tissues showed that penetration into the eye varied with race (albinos greater than pigmented) and dose. Intraocular ofloxacin levels, including in the vitreous, increased two fold when the eye was infected; however, penetration into the sclera, choroid, and retina was comparable in infected and noninfected eyes. These findings in humans and animals suggest that ofloxacin in a dose of a least 400 mg is a useful agent for the treatment of prophylaxis of ocular infections.

Systemic embolism secondary to chronic atrial fibrillation usually affect the cerebral circulation. The risk of a cerebrovascular accident in patients with chronic atrial fibrillation, irrespective of the aetiology, is 1.8 to 7.5 times that of the general population. The embolic risk is 18 times greater in patients with atrial fibrillation related to the rheumatic heart disease. The risk of patients under 60 years of age with idiopathic atrial fibrillation does not seem to be different to that of the general population. The risk of early recurrence of embolism in the first 30 days ranges from 8 to 15%. The risk of late recurrence varies but seems to be higher than that of the general population. The prognosis of embolic cerebrovascular accidents is poor with a 20% mortality rate. The benefits of preventive therapy of embolism with oral anticoagulants have been clearly established in rheumatic atrial fibrillation and in other indications. In non-valvular atrial fibrillation the benefits have to be compared with the risks of treatment. The incidence of hemorrhage due to anticoagulant therapy is between 3 and 5% per year per patient (about 1% of severe haemorrhage). Three randomised studies of primary prevention have shown a significant reduction of the embolic risk in non-valvular atrial fibrillation treated by warfarin compared to patients on placebo. Only one study has shown a significant reduction of the embolic risk in patients under 75 years of age with non-valvular atrial fibrillation treated with 325 mg/day of aspirin. However, anticoagulant therapy does not seem necessary in carefully selected patients under 60 years of age with idiopathic atrial fibrillation (less than 5% of all patients).

A case of paraplegia occurring after a spinal anaesthetic is reported. The 79-year-old man was admitted for a fractured neck of femur. Twenty years previously, he had had pharyngeal surgery and a tracheostomy. He had also undergone a prostatectomy for prostate cancer, and had been on oestrogen therapy for two years. He complained of dyspnoea at rest and his chest film showed diffuse pulmonary opacities. In order to avoid possible intubation and respiratory complications, spinal anaesthesia was performed without any problems in the L4 space. After the surgery, the patient recovered all his motor and sensory functions in the lower limbs. On the second postoperative day, he suffered from a motor paralysis of the right leg, which spread to the left leg on the fourth day. NMR imaging showed several vertebral metastases, together with anterior and lateral epidural invasion responsible for cord compression. Treatment with tetracosactide was begun, but the patient died six weeks later in his home, not having recovered any neurological function at all in his lower limbs. In fact, it was only after the procedure that the anaesthetist was informed that, at the time the prostate cancer had been diagnosed, vertebral body metastases, of which the patient had not been informed, were already present. The part played by the spinal anaesthetic in the occurrence of the paraplegia is not clear. It is reminded that such a technique should be used with extreme care in patients having a neoplasm with a very often high incidence of vertebral metastases.

The pharmacokinetics of ofloxacin orally administered were investigated at the steady-state in sixteen elderly patients older than 65 years. Patients with either urinary tract of respiratory tract mild infectious were divided into two age-dependent groups A and B. Group A: eight patients (65-80 years) received 200 mg of ofloxacin by the oral route every 12 hours and group B: eight patients older than 80 years, received 200 mg of ofloxacin by the oral route every 24 hours. The pharmacokinetic study was performed on treatment day 5. Plasmatic levels and urinary excretion of ofloxacin during 12 or 24 hours were assayed by means of high pressure liquid chromatography. Wide variations in plasma ofloxacin concentrations were observed within each group (Cmax range, group A: 1.9-9.2 mg/l, group B: 1.6-10.0 mg/l). Similar variability was observed for ofloxacin elimination parameters (CI/F, renal CI(R)/F) and half-life. In contrast, within-group and between-group differences in the volume of distribution adjusted for weight were not significant (group A: 1.22 +/- 0.44 l.kg; group B: 1.49 +/- 0.53 l.kg), but these values were approximately half those observed in the young adult. Plasmatic [CI/F] and renal clearance [CI(R)/F] of ofloxacin were correlated with creatinine clearance in both groups and in the overall population studied. Then the overall population was classified in terms of creatinine clearance [group 1: greater than 50 ml/min; group 2: less than or equal to 50 (minimum 20) ml/min]. The pharmacokinetics of ofloxacin in the elderly are characterized by a decrease in the volume of distribution and in plasmatic and renal clearances.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial fibrillation and atrial flutter are the most frequent arrhythmias encountered by the cardiologists in an everyday practice. External cardioversion, atrial temporary pacing and/or drugs are commonly and often successfully used in their treatment. The failures of these methods are rare, and for the patients who remain prone to arrhythmias or a recurrence with serious hemodynamic consequences, new therapies are presently under assessment. Electrical internal cardioversion can be performed when a permanent and bad tolerated atrial fibrillation is not managed by an external cardioversion. Elective ablation of a reentrant area will be probably the best solution to treat a recurrent atrial flutter or a junctional tachycardia by intranodal reentry. Finally, a radical solution consists to separate electrically the atria from the ventricles by interrupting totally or partially the A-V conduction. This can be performed by an endocavitary fulguration or an ablation by radiofrequency currents. To avoid recurrences, we usually use a pharmacological therapy. Permanent pacing is an exceptional solution.

A 63 year old man with ischemic heart disease underwent two sessions of catheter ablation in the inferior right atrium for poorly tolerated resistant and recurrent atrial flutter. After endocavitary mapping and comparison with surface recordings of the f waves, a shock of 50 joules was delivered to the zone situated anteriorly to the inferior vena cava, under the orifice of the coronary sinus and behind the tricuspid valve. Early recurrence of the arrhythmia led to a second attempt and another 50 joules shock was administered to the same area. Another short term recurrence led to definitive nodohisian interruption with a 270 joules shock. Thirty months later, the patient died suddenly during an episode of cardiac failure. Macroscopic examination of the right atrium showed a zone of parietal congestion measuring 4 x 3 cm with a very thin, translucid, central zone measuring 3 x 1.5 cm, just anterior to the inferior vena cava in the right atrial free wall. Histological examination of this zone showed an intense, mutilating fibrosis dissociating the muscular fibres, of the pectinate muscle and even replacing the myocardium in certain regions. In the Eustachian valve, there were muscular fibres, probably representing the posterior internodal pathway, which were also fibrosed. These observations suggest that: 1) in view of the extreme thinness of the atrial wall at the site of ablation there is a high risk of perforation even when right endoatrial catheter ablation is performed with low energy shocks; 2) the posterior internodal pathway does not seem to be an essential component for atrial flutter.

Almost 50 percent of patients with chronic heart failure die of sudden death often due to arrhythmia. In these patients the prognosis is related to the severity of myocardial lesions and also, probably, to the presence of ventricular arrhythmias. The potential severity of which can be assessed by various methods, including ECG, Holter monitoring, late potentials study and programmed ventricular stimulation tests. The first therapeutic measure to improve the prognosis of heart failure is to improve the myocardial function by prescribing converting enzyme inhibitors. The second measure consists of acting on potentially dangerous ventricular arrhythmias with few or no symptoms. Among antiarrhythmic agents, only beta-blockers and amiodarone seem to be valuable.

Internal cardioversion is a new method of treating atrial fibrillation. It consists in delivering an electric shock between an electrode positioned in the right atrium and a dorsal electrode. A quadripolar electrophysiological catheter is used as the proximal electrode, the two distal poles of which are used to locate the His bundle deflection. Care is taken that the electrode used for cardioversion is not in contact with the atrial wall by using biplane fluoroscopy and unipolar endocavitary recordings. Twenty-eight patients (18 men and 10 women) average age 55 years, underwent this treatment for chronic atrial fibrillation resistant to one or two attempts at external cardioversion. Each patient was given one or two shocks (average 1.68) in the same session. There were 22 immediate reversions to sinus rhythm, giving a primary success rate of 78.57%. Four patients relapsed in the 3 days following the procedure, giving a short term success rate of 64.28%. The minimum effective energy would seem to be 200 joules. The only rhythm complications were sinus bradycardia and/or atrioventricular block lasting a few seconds, both countered by prophylactic ventricular pacing : no traumatic complications due to electric shock were observed. The long term results show sinus rhythm maintained in 66.66% of patients at 6 months and more. In conclusion, internal cardioversion is an effective method of treating cardiac arrhythmias resistant to external cardioversion. The procedure would seem to be reliable and relatively atraumatic. The long term results are promising, particularly the stability of sinus rhythm which seems to be longer than after external cardioversion, by they need further confirmation.

The pharmacokinetics and pharmacodynamics of spinal narcotics are very important to determine dosage and intervals with bolus administration. Among known factors that may effect narcotic activity, lipid solubility seems to be the most important factor determining onset, greater dermatomal spread and longer duration of action than more lipid-soluble narcotics. This dermatomal spread is associated to a delayed respiratory depression which necessitates precautions and surveillance.

The authors report their experience involving 21 right endoatrial electroversions aimed at converting chronic atrial fibrillation resistant to external electroversion. All prior precautions were taken to ensure that the shocks were not in contact with an atrial wall nor over the node-His bundle (two dimensional radiological identification, endocavitary recordings). A total of 37 internal electric shocks were administered. Results were: 16 immediate successes out of 21 (72.2 per cent) and 12 short term successes out of 21 (57 per cent). The mean effective energy value was 200 Joules. There were no traumatic complications. The authors conclude that this technique is effective and reliable in the management of atrial fibrillation resistant to external electroversion.

This study aimed to compare the haemodynamic effects of two different glucose-free bupivacaine solutions is thirty patients aged more than 70 years (mean age 82 years) undergoing hip surgery under spinal anaesthesia. They were randomly assigned to two groups, group A to receive 2.5 ml of a 0.5% bupivacaine solution, and group B 10 ml of a 0.125% solution in normal saline. All the patients were therefore given the same dose of bupivacaine, 12.5 mg. Lorazepam (1 mg orally) was administered to all for premedication two hours beforehand. Those patients taking antihypertensive agents were given their last dose on the eve of surgery. Lactated Ringer's solution (500 ml) was infused to all before the spinal puncture. Systolic (Pasys), mean and diastolic arterial pressures, and heart rate, were recorded every minute before volume loading, and for 30 minutes after the start of the spinal anaesthesia. Ephedrine (3 mg every two minutes if required) was given whenever Pasys decreased by more than 30% of the pre-induction value. The upper level of sensory blockade was assessed by the pin-prick test, and the quality of motor blockade with the Bromage scale. The cephalad spread of the solutions was similar, as well as the haemodynamic profile in each group. The total dose of ephedrine required in each group was not significantly different. It may therefore be concluded that, in the elderly, the upper level of, and the haemodynamic changes due to, spinal anaesthesia do not depend on the concentration or the volume of glucose-free bupivacaine solution.

Objectifs A partir d’une large cohorte de patients infectes comparee a des temoins apparies, nous avons cherche a determiner l’incidence des complications infectieuses (locales ou endocardites) ainsi que les facteurs de risque d’infection sur stimulateur ou defibrillateur cardiaques (ISDC). Introduction L’incidence des ISDC variait de 0,5 a 5 %. Si certains facteurs favorisants (terrain debilite, sonde de stimulation preoperatoire, nombre de procedures) etaient bien connus, d’autres restaient a preciser tels l’anticoagulation ou le benefice d’une antibioprophylaxie. A ce jour, la definition et par consequent la prise en charge optimale des ISDC n’etait toujours pas consensuelles. Methodes et patients Les donnees demographiques et cliniques de patients presentant une ISDC entre 2004 et 2007 ont ete recueillies retrospectivement. Les cas infectes ont ete compares a des temoins apparies. Resultats 34 patients (âge moyen de 67,5 ans) remplissaient les criteres d’inclusion d’ISDC. Les manifestations cliniques les plus frequentes etaient des inflammations en regard de la loge du boitier (26 cas). Les examens cliniques et paracliniques ont mis en evidence 15 cas d’endocardite. Les germes les plus frequemment retrouves etaient les Staphylococcus epidermidis (66 %) et aureus (25 %). Les ISDC sont favorisees par une anticoagulation excessive mais prevenues par une antibioprophylaxie ( p Conclusion Cette etude met en evidence des facteurs de risque d’ISDC et permet de confirmer l’utilite d’une antibioprophylaxie. Une meilleure definition des criteres d’ISDC et de leurs facteurs favorisants devrait permettre d’ameliorer la prise en charge des patients.

The authors studied the possible consequences of the use of high frequency electrical currents of cardiac pacemaker function. Twenty-five unipolar pacemakers (22 single and 3 double chamber) were tested. They were connected to a pacing catheter, emerged in a saline bath and submitted to a modulated and then unmodulated current of 348 KHz in as many pacing modes as possible for each unit. Three dangerous deprogrammations were observed which could nevertheless be easily corrected. Five pacemakers immediately adopted the reversion mode specified by their manufacturer. The other changes observed only lasted as long as the electric current was applied. The commonest abnormality was a drop in the output voltage proportional to the energy delivered which sometimes led to true inhibition of the pacemaker. Two abnormal rate increases were observed reaching frequencies higher than 250/mn. No particular pacing mode seemed to protect the pacemakers from the effects of high frequency currents.

The pharmacokinetic profile of methohexital was studied in cirrhotic patients (n = 8), patients undergoing upper abdominal surgery (n = 8) and orthopaedic patients under general anaesthesia (n = 8). The total plasma clearance of methohexital was unchanged in cirrhotics: 54 +/- 22 l.h-1 (mean +/- s.d.) as well as in patients undergoing upper abdominal surgery: 60 +/- 14 l.h-1 in comparison to orthopaedic surgery: 70 +/- 24 l.h-1. The central volume and total volume of distribution and the distribution and elimination half-lives were similar between the three groups. Despite its hepatic dependent elimination, methohexital elimination kinetics were unchanged in patients undergoing upper abdominal surgery and in cirrhosis. Owing to the high hepatic extraction ratio of methohexital, its elimination should be influenced by the hepatic blood flow. The unchanged elimination kinetics presently observed in patients with cirrhosis or those undergoing upper abdominal surgery suggest that the hepatic blood flow is less diminished than expected in these patients.

The coordination polyhedron of the antimony atom in antimony tris-(O,O-diethyl phosphorodithioate) is a distorted capped octahedron with a stereochemically active lone pair in the capping position and approximately on a molecular pseudo triad axis which passes through the antimony atom.

A simple Landau-Ginzburg theory is shown to account qualitatively and semi-quantitatively for the memory effect anomalies of the susceptibility and the birefringence in thiourea. The importance of the gradient amplitude coupling energy in thiourea is emphasized. The possibility of creating a defect-induced locked incommensurate phase around any arbitrary temperature within the modulated phase is demonstrated. Such a locked phase will appear as a consequence of the condensation of a periodic defect concentration if extrinsic mobile impurities are allowed to interact for a sufficient time with a static modulation. We briefly discuss some aspects of such defect density waves in the physics of modulated structures Emploi d'une approche de Ginzburg, Landau pour rendre compte qualitativement et semi-quantitativement des anomalies de susceptibilite magnetique et de birefringence, liees a l'effet memoire, le couplage gradient amplitude jouant un role determinant dans la thiouree. Demonstration de la possibilite de creer, autour d'un point arbitraire dans la phase modulee du diagramme de phase, une phase incommensurable bloquee induite par defauts extrinseques