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Biomedical subjects

J Caron

Publications and source records attributed to J Caron.

At least 91 records · Page 5Linked to original sources
PubMed1988

[Late ventricular potentials. Clinical applications and relation to severe ventricular arrhythmias].

The recording of late ventricular potentials with high amplification cardiography (HAC) permits to identify patients presenting a risk of sudden death and ventricular tachycardia, especially in the later stage of myocardial infarction. Few authors have studied the prevalence of these potentials in other heart diseases presenting a risk of sudden death. Most series in the literature are too small to specify variations in the prevalence of these potentials according to the severity of the coronary disease. For this purpose, 835 patients including 535 coronary patients were evaluated with HAC compared to data from coronary angiography and Holter test. An automatic quantification method of the late potentials was used on 131 healthy subjects. The prevalence of late potentials is 32 p. cent after infarction, and 75 p. cent when a chronic ventricular tachycardia is present. These potentials retain their significance of tracers of ventricular arrhythmias in primary dilated myocardiopathies, with a prevalence of 25 p. cent reaching 50 p. cent in case of ventricular tachycardia. Their recording in the presence of idiopathic ventricular extrasystoles must be an indication to look for an underlying cardiopathy. It is possible to record them in other diseases especially in advanced valvular cardiopathies, as well as in right ventricular dysplasias with arrhythmia where their presence has a great diagnostic value.

Arrhythmias, Cardiac↗
PubMed1987

Propafenone versus disopyramide: a double-blind randomized crossover trial in patients presenting chronic ventricular arrhythmias.

In vitro and in vivo electrophysiological studies have shown that propafenone could be classified as a class I antiarrhythmic agent. The aim of this study was to investigate the short-term antiarrhythmic efficacy and safety of propafenone in 10 patients compared to disopyramide in a double-blind randomized protocol. Included patients suffered from ventricular arrhythmias with at least 60 ventricular premature beats (VPB) per hour refractory to at least two other antiarrhythmic agents. At the end of the control period and of the two treatment periods during which patients received either propafenone (300 mg three times a day) or disopyramide (200 mg three times a day), clinical examination, Holter recordings, electrocardiogram, and clinical laboratory tests were performed. The PR interval and the QRS interval were significantly increased with propafenone, but not with disopyramide. The cQT interval was not significantly changed by either propafenone or disopyramide. Heart rate was decreased with propafenone (p less than 0.05) with no change in the diurnal/nocturnal circadian ratio variation. Heart rate was significantly decreased with disopyramide only during the day. Five of nine patients in the propafenone group and two of nine patients in the disopyramide group showed a reduction in ventricular premature beats greater than 80%. Total resolution of severe arrhythmias (repetitive events) was seen in 5 of 8 patients with propafenone; 2 of 8 with disopyramide. Adverse events, when they occurred, were mild (visual disturbances, epigastric discomfort, changes in taste perception, transient atrioventricular block with propafenone, and photophobia with disopyramide), and did not require reduction or discontinuation of study drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Raynaud's phenomenon and finger necrosis after treatment of ovarian seminoma with bleomycin, vinblastine and 5-fluorouracil].

Bleomycin is sometimes at the origin of a Raynaud's phenomenon (RP). From the literature, there does not seem to exist a dose-dependent relationship. The phenomenon occurs early or late and often is resistant to various medications. The possible physiopathological mechanisms are: direct vascular toxicity, hypersensitivity vascularization, alteration of platelets activity, alteration of Willebrand's factor, and as predisposing factors: association to periwinkle alkaloids or hypomagnesemia.

Adult↗
PubMed1987

[Neuropathies and almitrine. 14 cases].

Previously reported cases of peripheral neuropathies occurring during almitrine therapy had only a few weeks follow-up after having stopped the drug. We have studied clinical and electrophysiological data 6 to 12 months after almitrine had been given up in 9 patients from a group of 14 whose epidemiologic, clinical, electrophysiological and pathological data had been registered. In 7 of them, without any chronic respiratory deficiency, almitrine was administered as almitrine bismésilate and raubasine, and in 7 others (6 with chronic respiratory deficiency) as almitrine bismesilate alone. In patients who had another possible cause of neuropathy, clinical disorders appeared after a lesser total quantity of almitrine (p less than 0.05). Clinical data were suggestive of sensory peripheral neuropathies of feet and lower third of legs. Electrophysiological data suggested distal axonopathy in spite of the absence of denervation: amplitudes of sensory potentials were reduced and nerve conduction velocities were moderately decreased. Biopsies revealed mild neurogenic atrophy of muscles and distal axonopathy. Clinical improvement was very slow and 6 to 12 months later, most of the patients still presented decreased vibration sense and ankle reflexes loss, but all of them were still improving. Amplitudes of sensory potentials and sensory nerve conduction velocities were significantly improved (p less than 0.05) but motor nerve conduction velocities were not (p greater than 0.05). Our study shows: 1) clinical, electrophysiological and pathological data similar to those previously reported; 2) subclinical disturbances of motor functions in lower limbs and sensory functions in upper limbs; 3) some patients presented with unusual signs: posture tremor (3 cases), painful legs and moving toes (1 case); 4) peripheral neuropathies may occur during almitrine therapy even in patients without any chronic respiratory insufficiency; 5) peripheral neuropathies occurred with lower doses in patients with other factors predisposing to neuropathies; 6) patients' improvement was very slow; 7) in 9 cases the imputability of these peripheral neuropathies to almitrine is plausible. We suggest not to prescribe almitrine without caution, especially in patients with other factors of neuropathy. Treatment should be regularly interrupted.

Aged↗
PubMed1987

[Prevalence of late potentials in ventricular tachycardias. Comparison with a control group].

High amplification electrocardiographic recording of ventricular late potentials was introduced a few years ago and seems to be a simple, reliable and reproducible method to identify patients at a high risk of sudden death and ventricular tachycardia, principally during the chronic phase of myocardial infarction. However, few authors have studied quantitatively the prevalence of late potentials in patients with ventricular tachycardia compared with a sufficiently large sample of healthy subjects. In this study 34 patients with sustained ventricular tachycardia (11 women, 23 men, mean age 58 years) and 131 healthy subjects (29 women, 102 men, mean age 29 years) underwent high amplification time-averaged ECG recording, and an algorithmic analysis of the tracings was conducted, using the Simson method. Three numeric parameters were used in the interpretation of the tracings: HFRMSA = mean RMS amplitude of the last 40 milliseconds of QRS; HFD40 = delay in signal decrease from amplitude 40 mu v to baseline, and delta QRS = difference in QRS duration with 0-250 Hz and 25-250 Hz filterings. Normal values, as determined from measurements in healthy subjects, were: HFRMSA above 27 mu v, HFD40 below 35 ms and delta QRS below 13 ms. Late potentials were present when at least one of these criteria was positive. When these norms were applied to patients with sustained ventricular tachycardia the prevalence of late potentials was 76%, rising to 90.4% in the subgroup of 21 patients with coronary disease. With the method thus defined the specificity for each criterion taken separately is 97.5%. According to the norms, only one control subject (0.8%) gave a false-positive result.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Serum IgG4 concentrations and allergen-specific IgG4 antibodies compared in adults and children with asthma and nonallergic subjects.

We describe the development of specific immunoassays for IgG4 protein and for allergen-specific IgG4 antibodies. We also measured the concentrations of IgG4 protein and determined the frequencies of detectable IgG4 antibodies to several common allergens in sera from adults and children with asthma and from nonallergic subjects. Serum concentrations of IgG4 protein increase with age but are not different in children with asthma and nonallergic children, nor does a raised serum concentration predict a severe clinical course in childhood asthma. IgG4 antibodies to milk and egg are common in children and adults and are more common in children with asthma than in nonallergic children less than 3 years of age. The presence of detectable IgG4 antibodies or a raised concentration of IgG4 protein in serum is not useful empirically as a diagnostic indicator of asthma but more likely results from antigen exposure occurring at mucosal surfaces.

Adolescent↗
PubMed1986

[Ventricular extrasystole. Which should be treated and how?].

The decision of whether or not to treat a ventricular extrasystole depends in the first instance on the benign or severe nature of the disorder, and on whether there is subjacent cardiopathy. The results of 24-hour Holter monitoring, exercise tolerance tests and clinical and echographic examinations will define the pathological character of a ventricular extrasystole and will indicate any subjacent cardiopathy. Electrophysiological exploration with programmed stimulation should be reserved for so-called lethal cases of arrhythmia, such as attacks of sustained ventricular tachycardia. Ischemic cardiopathy is by far the most frequent cause of ventricular extrasystoles. The two major risks of sudden death after myocardial infarction are due to left ventricular dysfunction and repetitive and/or complex ventricular extrasystoles, as well as to attacks of ventricular tachycardia. Heart patients presenting these disorders must receive urgent treatment with antiarrhythmics. Isolated, monomorphic ventricular extrasystoles are also treated in heart patients at risk if their frequency is greater than 10 per hour, measured by 24-hour Holter monitoring. In the absence of subjacent cardiopathies, the therapeutic indications are much less well defined. Approximately five per cent of subjects in a normal population present ventricular extrasystoles, the frequency of which, however, rarely exceeds 100 per 24 hours. Repetitive phenomena are only seen in 10 per cent of cases. Attacks of ventricular tachycardia are almost never seen. Ventricular extrasystoles that develop in apparently normal hearts, but which do not fulfill the above criteria, can be considered abnormal. Nevertheless, there is no categorical proof that these ventricular extrasystoles represent any risk, notably of sudden death.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Arrhythmia Agents↗
PubMed1986

[Continuous electrocardiographic recording with the Holter method in children. Indications and results].

There are relatively few reported studies of continuous electrocardiographic recordings by the Holter method in children. We report our experience of 296 24-hour recordings in 160 patients (average age 10.5 years), investigated for suspected or known cardiac arrhythmias. One hundred and ten patients (68.75%) had no organic heart disease and 6 patients (3.75%) had acquired lesions. Eighty-three patients (52%) were symptomatic. Sixty-three patients (39%) had normal recordings; 97 patients (61%) had a total of 126 arrhythmias. There were 45 cases of atrioventricular block, 24 cases of sinus node dysfunction, 39 cases of supraventricular arrhythmias and 18 cases of ventricular arrhythmias. Overall, 47.6% of these rhythm disturbances were diagnosed by Holter monitoring. This technique was particularly valuable in the diagnosis of arrhythmias in symptomatic patients, patients with arrhythmogenic cardiac lesions and in the detection and surveillance of postoperative arrhythmias in congenital heart disease, of pacemakers, of congenital atrioventricular block and of the chronic arrhythmias of childhood.

Adolescent↗
PubMed1984

[Sympathetic paraganglioma. Scintigraphic detection using a new labeled molecule, meta-iodobenzylguanidine].

Two cases of sympathetic paraganglioma are reported: one, benign, in a 20-years old woman with arterial hypertension and attacks of excessive sweating; the other, malignant and with bone metastases, in a 44-years old woman. Both were diagnosed by scintigraphy, using meta-iodobenzylguanidine as radionuclide. This new radiopharmaceutic agent has recently been introduced for the detection of phaeochromocytomas, but it seems to be a general tissue marker of catecholamine uptake and storage. Its use as a therapeutic compound may also be envisaged.

3-Iodobenzylguanidine↗
PubMed1981

[Klinefelter's disease and leydigiomas. A report of one case (author's transl)].

The authors present the case of a patient with Klinefelter syndrome who, at the age of 36 years, developed a multifocal Leydig cell tumour of the right testicle, presenting as hematuria. After orchidectomy, the patient developed an identical tumour in the remaining testes. This curious case of a patient in whom the clinical and laboratory features of Klinefelterer's syndrome, were masked by the Leydig cell tumour and vice versa, is analyzed. Study of this case, and a review of the literature of the three cases published in the past, offer no definitive solution to the problem of the possible link between the Leydig cell tumour and the Klinefelter syndrome, but a prospective study protocol is suggested with such an aim in mind. More careful clinical and laboratory evaluation of populations of Klinefelter's syndrome and Leydig cell tumours should provide a solution. More routine therapy of Klinefelt syndrome should possibly avoid the development of complications in the form of testicular Leydig cell tumours by causing inhibition of useless and excessive pituitary actions by the administration of androgens immediately after puberty.

Adult↗
PubMed1980

[Computer tomography examination of the diaphragmatic pillars. Value during the study of the postero-inferior mediastinum (author's transl)].

The authors review the results of 100 computer tomography examinations of the normal thoraco-abdominal region and define the radiological anatomy of the posterior submediastinal space limited by the pillars of the diaphragm, which can almost always be investigated by computer tomography. Study of this posterior submediastinal space in 276 cases, by means of a strictly defined procedure, was used to illustrate the elementary signs encountered: effacement of the pillars, loose appearance of the pillars with absence of the median arcate ligament, presence of an abnormally sized structure in the middle of the space. The main indications for computer tomography examination of this region are for diagnosis of an opaque tumor of the postero-inferior mediastinum, and the investigation of extensions of bronchial cancers, regionally located neoplasms and lymphomas.

Blood Vessels↗