Better understanding of the filtration characteristics in the flexible fibre filter module (3FM).

This study is about the particle retention and filtration characteristics of fibre filter. Four laboratory scale fibre filters with different heights were used in parallel at various packing densities and filtration velocities. Of all of the operating parameters studied, filtration velocity had the most influence. Contrary to general theories, pressure drop increases slightly during the filtration in spite of the continuous retention of particles. This may have occurred because of large porosity of the packing (about 93%). This might be considered an advantage of the filter and something that makes it economic. The higher the filtration velocity, the larger the mass of particles retained in the filter. For filtration velocities of 20 and 40 m/h, particles smaller than 5 microm are retained as proven by the particle size distribution at the inlet and outlet.

Enhancing flexible fiber filter (3FM) performance using in-line coagulation.

A new packing for deep bed filtration using Flexible Fibers has been proposed and developed on a very large scale for tertiary treatment of wastewater. The purpose of this study is to check the possibility of using this technology for the production of drinking water from surface water. In this study, the feasibility of the fiber filter application on water treatment was examined and the removal efficiency of fiber filter was improved using an in-line coagulant injection method. The experiments were carried out at pilot scale. The filter was packed with bundles of polyamide fibers with a bed porosity of 93%. Nak-dong River was used as the filter influent water and alum, PSOM, and PAC were used as the coagulants. The coagulants were injected by the in-line injection method. Small dosages (1-5 mg/L) of the polymeric coagulants (PSOM and PAC) showed an increase of removal efficiency compared to the operation without coagulants. Specifically, 1 mg/L of PAC showed the longest filtration time. Considering filtration time, filtrate quality, and filtered volume, the filtration velocity of 120 m/hr was chosen as an optimum value. For long-term operations, the effluent quality was 0.4 NTU and the removal efficiency was stable for the given optimum conditions.

Feasibility of routine transradial coronary angiography: a single operator's experience.

The aims of this study were to assess the feasibility of routine transradial coronary angiography in a standard population of patients with presumed coronary artery disease over a period of time long enough to allow for technical evolution and evaluation of a single operator's learning curve, and to provide data for a randomized comparison versus the femoral approach. Between June 1994 and March 1997, transradial angiography was attempted in 1,000 patients. Approximately 25% of these patients were excluded because of an abnormal Allen test. Except in the case of acute myocardial infarction, there was no selection based on symptoms, age, sex, weight or size in the absence of double internal mammary artery bypass graft operation or simultaneous right heart catheterization. Symptoms and angiographic results were typical of a standard population. The right radial approach was used in 95% of the cases for ease of handling and comfort of a right-handed operator. Radial artery puncture and catheterization success was obtained in 97.6% of the cases; the left coronary artery was selectively catheterized in 100%, right coronary artery in 98%, left ventricle in 96.9%, mammary artery grafts in 100% and saphenous grafts in 97.2%. Average procedure duration was 18 +/- 9 minutes, and decreased progressively with experience and catheter strategies. The optimal catheter selection would seem to be a single catheter, either left Amplatz or Champ, for both coronary arteries. Two coronary complications and 3 transient neurological complications occurred, but no clinically significant vascular complications requiring surgery or transfusion were reported. Transradial angiography seems to be a routine approach that should now be compared with the femoral approach and supersede the brachial approach whenever possible.

[Comparative study of the global left ventricular ejection fraction obtained by ECG gated perfusion MIBI and thallium scintigraphy]. / Etude comparative de la fraction d'éjection globale du ventricule gauche obtenue par l'analyse couplée à l'ECG de la tomoscintigraphie de perfusion au MIBI et au thallium.

The isotopic LVEF was measured by a planar method with injection of a product visualising the ventricular cavity. Perfusion was assessed by Thallium and sesta MIBI. The investigation of ischaemia and assessment of wall motion in the coronary patient, therefore, requires two isotopic methods. The Cedars Sinai group have developed a programme allowing acquisition of a perfusion tomoscintigraphy in the cardiac cycle after injection of MIBI. This programme automatically detects the endocardial borders and calculates the LVEF. This provides a study of function and perfusion in a single investigation. However, MIBI is not considered by all as a good marker of viability, contrary to Thallium. And the acquisition of Thallium tomography with ECG gating may pose problems because of the low counting statistic. Several authors have therefore studied the possibility of using it for assessing left ventricular function. The authors have then compared LVEF with MIBI and with Thallium in 72 patients. The Thallium LVEF was 33.62% +/- 15.79%; that of MIBI was 32.51% +/- 14.73%. ThalEF = MIBI EF x 1.02 + 0.34 (r = 0.955). The mean of the standard deviation was 1.09. In conclusion, the EF measured by Thallium tomography with ECG gating was closely correlated to that obtained with MIBI. These results suggest that myocardial viability, ischaemia and function may be studied in routine daily practice with a single injection, so improving patient comfort and reducing the costs of the procedures.

[Coronary angiography by a radial artery approach: feasibility, learning curve. One operator's experience]. / Coronarographie par voie radiale. Faisabilité, courbe d'apprentissage. Expérience d'un opérateur.

The aim of this study was to assess the feasibility of the radial artery approach for coronary angiography in a standard population of presumed coronary patients and to continue the assessment for a sufficiently long period of time to perfect the technique, evaluate the learning curve and prepare a randomised comparison with the femoral approach. The radial artery was used for coronary angiography in 800 patients after exclusion of about 25% of patients, mainly because of a negative Allen's maneuver. With the exception of acute myocardial infarction, there was no selection based on symptoms and transradial catheterisation was attempted irrespective of age, sex, weight or height. The representative nature of the study population was confirmed by the results of the procedure (normal: 20%, single vessel disease: 30%, double vessel disease: 26%, triple vessel disease: 18% and left main disease: 5.4%). The right radial artery was used in 94% of cases. Successful radial puncture/catheterisation was obtained in 97% of cases: 100% of left coronary arteries and 99% of right coronary arteries were catheterised, the left ventricle in 98% of cases, the internal mammary arteries in 100%, and venous bypass grafts in 95%. The average duration of the whole procedure was 19 +/- 9 minutes. This decreased regularly with operator experience and judicious choice of catheters. The best choice seemed to be a single catheter for both coronary arteries, either an Amplatz or a Champ catheter. There were two probably avoidable coronary complications and two transient neurological events but no clinically significant vascular complication. The radial artery seemed to be a good approach for routine coronary angiography and may now be compared with the femoral approach. It should help expand the practice of ambulatory coronary angiography.

[Pro-arrhythmia effect of pyridostigmine. Apropos of a case]. / Effet proarythmique de la pyridostigmine. A propos d'un cas.

A coronary patient with myasthenia gravis with a previous myocardial infarction presented with severe ventricular arrhythmias after the replacement of neostigmine by pyridostigmine for the treatment of the myasthenia. These arrhythmias were resistant to antiarrhythmic therapy associating betablockers and amiodarone throughout treatment with pyridostigmine but regressed when this drug was withdrawn. A test of reintroduction of pyridostigmine under medical surveillance led to the reappearance of the ventricular hyperexcitability, so confirming the responsibility of this drug. This would seem to be the first reported case of severe ventricular arrhythmias due to a proarrhythmic effect of pyridostigmine. The possible mechanisms of this effect are discussed.

[Diagnosis of a Q3 wave: value of the inspiratory test]. / Diagnostic d'une Q3 : valeur du test inspiratoire.

The aim of this study was to determine the value of the inspiratory test on isolated Q waves in Lead III. The ECGs of 25 normal young adults with isolated Q waves in Lead III were compared with those of 86 patients with documented postero-diaphragmatic myocardial infarction (62 chronic, 21 recent). The criteria of abnormality of the Q waves were : duration 0.04 sec and amplitude 25% of R3. Thirty six per cent of the ECGs of the 25 normal subjects with the Q3 pattern met these criteria. Q3 post infarction changes may lose these pathological characteristics; they were absent in 23% of patients with chronic infarction and 17% of patients with recent infarction. Isolated Q3 changes, therefore, pose a difficult diagnostic problem. Lyle 's inspiratory test which is still widely used as a discriminating factor led to a reduction of the pathological Q wave amplitude and duration, both in normal subjects and in-patients who had documented infarction. The only difference between the 2 groups was the percentage decrease. Inspiration led to a reduction in the amplitude and duration of the Q3 waves in 89% of normal subjects, 58% of patients with chronic infarction and 20% of patients with recent infarction. Inspiration may even lead to the complete disappearance of the Q3 waves (10% of chronic infarcts). No correlations were found between the severity of the anatomical lesions (coronary or ventricular) and the reduction of Q3 waves. These results suggest that Lyle 's inspiratory test is a poor method of discriminating between normal and pathological isolated Q3 waves.

New indexes for assessing aortic regurgitation with two-dimensional Doppler echocardiographic measurement of the regurgitant aortic valvular area.

Direct examination of the aortic orifice at the level of the aortic valves (aortic valvular orifice area, AVOA) in the short-axis plane was performed with a 3 MHz two-dimensional pulsed Doppler echocardiographic apparatus. The AVOA was mapped with the Doppler gate to detect or rule out the presence of a regurgitant aortic valvular area (RAVA) established by recording of abnormal diastolic Doppler signals on a "yes or no" basis. A group of 12 normal subjects and 83 patients, including 40 patients with aortic regurgitation proven by aortography, were investigated with this procedure. In the 38 patients with aortic regurgitation diagnosed by Doppler echocardiography (diagnostic sensitivity 95%, specificity 100%), planimetric measurements of the RAVA and AVOA were performed with calculation of two indexes: the RAVA/square meter of body surface area and the RAVA/AVOA ratio. These indexes correlated well with independently performed angiographic grading on a three-point scale (r = .87 for the RAVA, .88 for the RAVA/AVOA; p less than .001), with highest significance of differences in mean values among each grade of severity found for the RAVA/AVOA (p less than .001). In addition, Doppler echocardiography identified the anatomic valvular site of the lesion, and we confirmed the site during surgery.

[Even distribution of myocardial protection in surgery of the coronary arteries: successive cardioplegia at the origin of the aorta and at the coronary sinus]. / Pour une répartition uniforme de la protection myocardique dans la chirurgie des coronaires: cardioplégie successive dans la racine de l'aorte et dans le sinus coronaire.

In coronary bypass surgery myocardial protection by injection of a cardioplegic fluid is made uneven by the presence of stenotic segments. In order to make it even, the authors suggest that the fluid should be injected first into the aortic origin, then into the coronary sinus. This method should provide greater safety when multiples bypasses are performed and in cases of impaired left ventricular function.

[Anti-arrhythmic effects of injectable amiodarone. Apropos of 100 cases]. / Les effets antiarythmiques de l'amiodarone injectable. A propos de 100 cas

The effects of amiodarone by injection have been studied in 100 patients. 50% of these patients were in cardiac failure. Amiodarone was given intravenously over 30 seconds in a dose of 300 mg; in 15 of the patients a further dose of 150 mg was given after ten minutes. Amiodarone was found to be particularly effective in the tachy-arrhythmias (90% successful) in which it brought about slowing (18 cases out of 30) or conversion (17 cases out of 30). Just as good results were obtained for the atrial tachycardias (90% success rate) and in the junctional tachycardias. This treatment is less effective for atrial flutter (50% successful) and for ventricular arrhyrthmia, in which the success rate was only 60%. It is possible to use the defibrillator after amiodarone has been administered. This drug is well tolerated, and no increase in cardiac failure has been noted in these patients. There does remain, however, the possibility of hypotension and perhaps of circulatory collapse, which is rapidly reversable; this is probably due to vasodilator activity. Intracavitary studies in 8 patients have shown that amiodarone causes slowing of sino-atrial and of atrio-ventricular conduction. Amiodarone may equally worsen a distal conduction defect. The uses for this anti-arrhythmic drug, which is particularly effective at the atrial level, are discussed in this paper.