PubMed Health⌕ Search

Biomedical subjects

I Bourgeois

Publications and source records attributed to I Bourgeois.

At least 19 recordsLinked to original sources
PubMed2000

Assessment of gastric emptying using a low fat meal: establishment of international control values.

OBJECTIVE: The diagnosis of gastroparesis implies delayed gastric emptying. The diagnostic gold standard is scintigraphy, but techniques and measured endpoints vary widely among institutions. In this study, a simplified scintigraphic measurement of gastric emptying was compared to conventional gastric scintigraphic techniques and normal gastric emptying values defined in healthy subjects. METHODS: In 123 volunteers (aged 19-73 yr, 60 women and 63 men) from 11 centers, scintigraphy was used to assess gastric emptying of a 99Tc-labeled low fat meal (egg substitute) and percent intragastric residual contents 60, 120, and 240 min after completion of the meal. In 42 subjects, additional measurements were taken every 10 min for 1 h. In 20 subjects, gastric emptying of a 99Tc-labeled liver meal was compared with that of the 99Tc-labeled low fat meal. RESULTS: Median values (95th percentile) for percent gastric retention at 60, 120, and 240 min were 69% (90%), 24% (60%) and 1.2% (10%) respectively. A power exponential model yielded similar emptying curves and estimated T50 when using images only taken at 1, 2 and 4 h, or with imaging taken every 10 min. Gastric emptying was initially more rapid in men but was comparable in men and women at 4 h; it was faster in older subjects (p < 0.05) but was independent of body mass index. CONCLUSIONS: This multicenter study provides gastric emptying values in healthy subjects based on data obtained using a large sample size and consistent meal and methodology. Gastric retention of >10% at 4 h is indicative of delayed emptying, a value comparable to those provided by more intensive scanning approaches. Gastric emptying of a low fat meal is initially faster in men but is comparable in women at 4 h; it is also faster in older individuals but is independent of body mass.

Adult↗
PubMed1997

Gracilis urethral myoplasty: preliminary experience using an autologous urinary sphincter for post-prostatectomy incontinence.

PURPOSE: We investigated the effect of a neurovascular intact gracilis muscle urethral wrap to restore urinary continence in men with severe stress urinary incontinence after radical retropubic prostatectomy. MATERIALS AND METHODS: Three men with stress incontinence after radical retropubic prostatectomy and external beam radiation therapy for adenocarcinoma of the prostate underwent gracilis urethral myoplasty. Video urodynamic evaluation and cystourethroscopy revealed Valsalva leak point pressure of less than 40 cm. water and a damaged urinary sphincter mechanism in all 3 patients. One man underwent concomitant ileocystoplasty. RESULTS: At 6 to 24-month followup all patients reported improved continence. Mean Valsalva leak point pressure increased from 26.3 +/- 3.2 cm. water before to 83.0 +/- 32.1 cm. water after surgery. The gracilis muscle urethral wrap did not have a deleterious effect on erectile function or ambulation. Complications included 1 wound infection. CONCLUSIONS: An autologous gracilis muscle urinary neosphincter can be constructed in the bulbous urethra in a fashion similar to that of the artificial urinary sphincter with encouraging results in this preliminary series. The gracilis neosphincter may be an alternative to the artificial sphincter, especially in patients at higher risk for complications, such as after radiation and cryotherapy.

Aged↗
PubMed1997

Gracilis urethromyoplasty--an autologous urinary sphincter for neurologically impaired patients with stress incontinence.

PURPOSE: To investigate the effect of a neurovascularly intact gracilis muscle urethral wrap, to be used to restore urinary continence as a transposed urinary sphincter graft, in patients with neurogenic lower urinary tract dysfunction. METHODS: Five neurologically impaired men with a denervated and damaged urinary sphincter mechanisms were treated. The etiology of sphincteric insufficiency included sphincter denervation in three patients, external sphincterotomy in one, and urethral trauma due to a chronic indwelling catheter in one. All patients underwent gracilis urethromyoplasty sphincter reconstruction. Two patients also underwent concomitant ileocystoplasty and one patient ileocystostomy because of poor bladder compliance and a bladder capacity of < 200 ml. RESULTS: The gracilis urethromyoplasty functioned as a new autologous sphincter with follow-ups ranging from 6-35 months. The surgery was successful in four patients. Three of the four patients were managed with intermittent catheterization, and one managed by ileocystostomy. The fifth patient continued to require an indwelling urethral catheter. CONCLUSION: Gracilis urethromyoplasty achieves compression of the urethra using a neurovascularly intact muscle graft. The functional urethral closure, obtained from the gracilis muscle wrap, assures dryness, and permits intermittent self-catheterization. It also avoids the risks of infection, erosion, or malfunction associated with the artificial urinary sphincter. The potential exists for electrical stimulation of this muscle graft to allow volitional control of the neo-sphincter mechanism, and voluntary voiding.

Adult↗
PubMed1996

Cost benefit analysis of single and dual chamber pacing for sick sinus syndrome and atrioventricular block. An economic sensitivity analysis of the literature.

The benefits of dual (DDD) over single chamber pacing (VVI) have been demonstrated in haemodynamics, exercise capacity, quality of life and reduced complications in atrioventricular block and sick sinus syndrome. The literature was reviewed to provide complication rates for dual and VVI pacing. Cost calculations were based on United Kingdom 1991 prices. Over a 10-year period, a computer model calculated the incidence and prevalence of atrial fibrillation, stroke, permanent disability, heart failure and mortality in six patient categories: sick sinus syndrome paced VVI, sick sinus syndrome upgraded to DDD, sick sinus syndrome paced DDD from outset, atrioventricular block paced VVI and those upgraded to DDD and atrioventricular block paced initially DDD. Calculations were based on intention to treat. The 10 year survival with DDD vs VVI pacing was 71% vs 57% in sick sinus syndrome and 61% vs 51%, respectively, in atrioventricular block. In both indications the prevalence of heart failure in the 10 year survivors was 60% lower with DDD pacing. In sick sinus syndrome patients paced VVI, 36% had severe disability while only 8% experienced this with DDD pacing. For atrioventricular block the figures were, respectively, 22% vs 3%. The difference in 10 year cumulative cost between VVI and DDD is 13 times the purchase price of a VVI pulse generator for sick sinus syndrome and 7 times for atrioventricular block. In the third year after implantation the cumulative costs of DDD were lower than for VVI for both indications. Dual chamber pacing for both indications, sick sinus syndrome and atrioventricular block, is both clinically and cost effective.

Atrial Fibrillation↗
PubMed1995

Neurovascular intact muscle transposition for anal sphincter repair. Experimental model and experience with dynamic pacing.

PURPOSE: To study muscle behavior for anal sphincter repair, radiologic, manometric, and histologic techniques in a dog animal model have been used. Special attention was given to the problem of resting length of the transposed muscle. METHODS: The semitendinosus muscle of the dog could be transposed successfully to create a new anal sphincter based on an intact neurovascular pedicle. The parallel-fibered muscle was split at its distal end and encircled around the anal canal. Manometry was performed intraoperatively and postoperatively. A sufficiency high basal and squeeze pressure had to be obtained intraoperatively to guarantee a final continent neosphincter. This could be realized by a progressive stretching of the muscle until maximum squeeze is reached. In one animal a pacemaker was implanted, and postoperatively a fixed sphincter stimulation protocol was started. Muscle biopsies of the normal anal sphincter and the neosphincter were taken. RESULTS: 1) Muscle transposition gave a high degree of continence in this experimental model, with a mean resting pressure of +/- 40 mmHg and a mean squeezing pressure of +/- 73 mmHg. 2) Electric stimulation of the neosphincter in one animal influenced the resting pressure but not the squeeze pressure. 3) Muscle fiber type composition changed toward a slow fiber type composition after transposition of the fast muscle and even more after stimulation. CONCLUSIONS: 1) Creation of a muscle cuff around the anal sphincter can substitute normal anal sphincter. 2) Adequate stretch of muscle fibers is essential for continence. 3) Electrical pacing helps preserve resting tension and subsequent continence.

Anal Canal↗
PubMed1992

Effect of spinal cord stimulation on regional myocardial perfusion assessed by positron emission tomography.

Spinal cord stimulation (SCS) can relieve symptoms in patients with severe angina pectoris refractory to conventional medical or surgical therapy. This symptomatic improvement may result from decreased myocardial ischemia. To test this hypothesis, positron emission tomography (PET) and potassium-38 as a flow tracer were used in 8 patients for the quantitative evaluation of regional myocardial perfusion at rest and after exercise, before and during SCS. Potassium uptake was evaluated as myocardial clearance (flow times net extraction) in ml/min/100 g. Tomographic segments were categorized as nonaffected and affected on the basis of the absence or presence of arterial stenosis on coronary angiography and on the basis of thallium scintigraphic data. In nonaffected segments, before SCS, regional myocardial clearance significantly increased from rest (28 +/- 4) to exercise (47 +/- 13 clearance units; p less than 0.004). A similar increase occurred after SCS. In affected segments, before SCS, regional myocardial clearance barely increased (p = 0.065) from rest (26 +/- 6) to exercise (33 less than or equal to 12). In comparison, after SCS, the resting regional myocardial clearance was slightly elevated (29 +/- 8) reflecting an increased double product, but did not increase (p = 0.192) with exercise (34 +/- 12). However, the magnitude and duration of ST-segment depression decreased during treatment with SCS. Anginal pain occurred in all patients during control exercise, but was attenuated in all but one with SCS. These results indicate that SCS improves exercise-induced angina and electrocardiographic signs of ischemia but this influence does not appear to be mediated by changes in regional myocardial perfusion.

Aged↗
PubMed1990

Dynamic aortomyoplasty to assist left ventricular failure.

The efficacy of skeletal muscle contractile force to augment left ventricular function has been demonstrated experimentally and clinically by the cardiomyoplasty procedure. Another approach in biomechanical cardiac assistance is the use of electrostimulated skeletal muscle in an extracardiac position. We describe an autologous counterpulsating device using the native ascending aorta as a ventricular chamber wrapped by an electrostimulated latissimus dorsi muscle flap (LDMF). This model avoids thrombotic complications observed in skeletal muscle neo-ventricles associated with prosthetic chambers. In 8 goats, a right LDMF was transferred to the thoracic cavity by removal of the second rib. In 4 goats, the diameter of the aorta was enlarged by surgical implantation (using lateral clamping) of an autologous pericardial patch. The LDMF was wrapped around the ascending aorta and electrostimulated using an external diastolic pulse generator connected to a sensing myocardial lead and to LDMF pacing electrodes. Hemodynamic studies were performed (left ventricular, aortic, and pulmonary artery pressures and rate of rise of left ventricular pressure). The LDMF diastolic counterpulsation was performed using a burst of 30 Hz, with a delay from the R wave adjusted to provide optimal diastolic augmentation. Percent increase in the subendocardial viability index was calculated during unassisted and assisted cardiac cycles (1:2) at baseline and after acute heart failure induced by the administration of high doses of propranolol hydrochloride (3 mg/kg intravenously). Diastolic aortic counterpulsation by the stimulated LDMF resulted in a significant improvement in the subendocardial viability index both at baseline and after induced cardiac failure in both groups, though the increase was greater in the group with aortic enlargement.

Animals↗
PubMed1990

Atrial cardiomyoplasty after Fontan-type procedures.

The purpose of right atrial cardiomyoplasty is to increase atrial-pulmonary flow in patients undergoing Fontan-type procedures. We developed two surgical techniques to bypass the right ventricle, followed by right atrial cardiomyoplasty with a stimulated latissimus dorsi muscle flap (LDMF). In 10 goats, the left LDMF was transferred into the chest by removal of the second rib. After sternotomy, the right atrial appendages of five goats (group 1) were connected to the distal main pulmonary artery with polytetrafluoroethylene tubing and the proximal pulmonary trunks were ligated. In the other five goats (group 2), under cardiopulmonary bypass, bioprosthetic valves were implanted into the inferior venae cavae. The tricuspid orifice was closed, and the atriopulmonary connection was performed. The left LDMF was sutured over the right atrium and stimulated using synchronous 30-Hz bursts of impulses delivered by a Medtronic Cardiomyostimulator. Hemodynamic studies were performed in the acute phase. Right atrial, pulmonary arterial, and aortic pressures were assessed. Cardiac output was measured using ultrasonic flow studies. LDMF stimulation restored pulsatile pressure patterns in the pulmonary artery and increased the cardiac output. These observations were more evident in the model with caval valvular implant. This functional "ventricularization" of the right atrium could improve long-term results after Fontan-type procedures and extend operative indications. Chronic experimental studies are necessary to evaluate the diastolic and systolic functions of the neo-right ventricle.

Animals↗
PubMed1988

Dynamic cardiomyoplasty: a surgical approach for ventricular assistance.

Dynamic cardiomyoplasty involves the use of an electrically stimulated skeletal muscle wrapped around part of the heart to restore or augment myocardial contractility. In our approach, a Latissimus Dorsi muscle flap (LDMF) is transferred to the heart via a partial resection of the second rib, and sutured around the ventricles. The muscle flap is stimulated in synchrony with the heart contractions with bursts of impulses delivered by a "Cardio-Myostimulator" implantable pulse generator via intramuscular electrodes. The object of this study was to identify features of muscle stimulation and to measure the efficacy of L.D. cardiomyoplasty in increasing cardiac output, using an ultrasonic Doppler technique. This report shows the results obtained for goats in which such procedures were performed. Ultrasonic measurements were recorded at the time of cardiomyoplasty and 3-6 months later, during which period the muscle was put progressively into use by slowly increasing the burst frequency content, number of pulses as well as the heart-muscle contraction ratio (3:1, 2:1, 1:1). This postoperative muscle stimulation protocol takes into account the delay of gradual conversion of fast-twitch glycolytic muscular fibers into slow-twitch oxidative, fatigue-resistant fibers, as well as the healing time after cardiomyoplasty required for the muscle flap to recover collateral blood circulation and to adhere to the heart. Results show that synchronous burst stimulation of the muscle flap increases the blood peak velocity in the descending aorta (+36 +/- 8%) and increases the left ventricular stroke volume (+70 +/- 14%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Direct diaphragm stimulation.

Direct diaphragmatic stimulation is effective without discomfort to the patient and without muscular fatigue. However, some quadriplegic patients may require synchronous expiratory stimulation in order to obtain complete and permanent respiratory autonomy. Now it will be necessary to undertake further studies of the indications for direct diaphragm stimulation.

Aged↗
PubMed1985

[Assisted respiration by stimulation of the diaphragmatic muscle. A case].

Direct electrical stimulation of the diagram has resulted in physiological functioning in a quadriplegic patient. Mechanical ventilation could be partly withdrawn with 13-hour periods of "respiration". During the 2-month stay in hospital, 90 hours of respiration were obtained by stimulation. The patient died 8 weeks after the operation.

Aged↗
PubMed1985

Simultaneous recording of atrial and ventricular monophasic action potentials: monophasic action potential duration during atrial pacing, ventricular pacing, and ventricular fibrillation.

A newly developed transvenous suction electrode was used in dogs to record monophasic action potentials (MAPs) from the right atrium and right ventricle simultaneously. Continuous MAP recordings could be made from the same endocardial site for test periods of 1.5 hours. Left ventricular pacing at increasing heart rates resulted in a statistically significant decrease of right ventricular MAP duration. A high degree of correlation was found between right ventricular MAP duration at 90% of repolarization and the QT interval during both right atrial and left ventricular pacing. At the onset of ventricular fibrillation (VF), right ventricular MAP duration shortened to 25% of the value obtained during left ventricular pacing at a cycle length of 250 ms. A cyclic alternation in amplitude of the right ventricular MAPs was observed during VF. Fast Fourier Transform Analysis of right ventricular MAPs during VF showed a significant dominant frequency at 12 Hz, with no levels of interest beyond this frequency. This observation might prove to be useful in elaborating a new algorithm for the automatic detection of ventricular fibrillation.

Action Potentials↗
PubMed1984

Clinical experience with implantable devices for control of tachyarrhythmias.

Pacing is becoming an accepted form of treatment for reentry tachycardias. The different pacing modalities available and experience with a patient-activated antitachycardia pacemaker are presented in this paper. This system has bidirectional communication between pacemaker and pacemaker-activator and between pacemaker and prescription formulator (which is a sophisticated portable stimulator used for non-invasive electrophysiological evaluation of the system). This pacemaker was implanted in 18 patients with drug-resistant tachycardias. Six patients had ventricular tachycardia, 3 had A-V nodal reentrant tachycardia, 4 had the concealed accessory pathway, and 5 had the WPW syndrome. In the 3 months before implantation the mean number of admissions for termination of tachycardia was 2.1 per patient-month. During a follow-up period of 3-26 months only 6 patients were admitted once for termination of tachycardia (0.02 admissions per patient-month). The reasons for admission of these 6 patients were: defective pacemaker activator in 2 patients, inadequate control of tachycardia in 2 patients, inappropriate use of the device in 1, and inadequate intake of medication in 1. All these problems were solved easily. Eight pacemaker activators required reprogramming, which was done in 5 patients on an out-patient basis. The interval scanning mode was used in 9 patients. Nine patients required more than 2 stimuli for reproducible termination. A step-wise increase in number of stimuli was used in 5 patients. This system has proven to be a safe and effective form of treatment of drug-resistant supraventricular and ventricular tachycardias and has resulted in marked improvement of the quality of life of these patients.

Adult↗
PubMed1983

New low energy transvenous cardioverting and pacing electrode.

A new endocardial catheter electrode (Medtronic model 6880) is described which can be used for ventricular pacing and for intracavitary cardioversion and defibrillation. Initial results in dogs and preliminary clinical trials in humans indicate that this catheter will extend the usefulness of electrical stimulation therapy for treatment of life-threatening tachyarrhythmias.

Animals↗