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Biomedical subjects

R Gérard

Publications and source records attributed to R Gérard.

At least 19 recordsLinked to original sources
PubMed1992

[Comparative effects of anti-arrhythmia agents on ventricular refractory period and prevention of ventricular tachycardia induced by stimulation].

The efficacy of antiarrhythmic drugs is attributed to their actions on the refractory periods or conduction velocity in the reentry circuit. The aim of this study was to determine the relationship between these factors and the prevention of electrically inducible ventricular tachycardia (VT). Twenty-seven patients with sustained monomorphic postinfarction VT underwent programmed stimulation under basal conditions and after administration of oral Class I antiarrhythmic drugs. The protocol of stimulation consisted of delivering one to three extrastimuli to the right ventricular apex on two basic cycle lengths. Sustained VT was induced in all patients. After the same protocol under antiarrhythmic therapy (1 to 5 tests, average 2.9 +/- 1) sustained VT could not be induced in 12 patients (44%). The effective right ventricular refractory period was significantly increased in patients without inducible VT under treatment (247 +/- 18 versus 302 +/- 26 ms). The increase in the right ventricular effective refractory period in patients with persistence of inducible VT was much less (from 270 +/- 28 to 287 +/- 30 ms). In all patients in whom several antiarrhythmic drugs were tested the right ventricular effective refractory period was higher when the treatment was judged to be effective (299 +/- 27 ms) than ineffective (272 +/- 27, p < 0.02). The prevention of inducible VT by class I antiarrhythmic agents seems therefore to be related to their effect on the ventricular refractory period.

Anti-Arrhythmia Agents↗
PubMed1979

[Mitral valve prolapse and spasmophilia in children and adolescents].

71 cases of mitral valve prolapse (MVP) in the child and adolescent with an age range of 3 to 20 years were reviewed. The clinical symptoms, electrocardiography and catheter and angiographic data of this mitral abnormality were analysed. A systematic study of the electrocardiogram showed a tendency to spasmophilia in 68% of cases. The serum calcium, phosphate and magnesium levels were normal in 90 to 95% of patients. A reduced erythrocytic magnesium level seems to have been found in some patients. It is interesting to observe the similarity between the clinical signs in MVP and in spasmophilia. These clinical, biochemical and electrocardiographical results justify the systematic investigation of children and adolescents with MVP, with a view to the diagnosis of spasmophilia.

Adolescent↗
PubMed1979

[Mitral valve prolapse and spasmophilia in the adult].

75 cases of mitral valve prolapse (MVP) for which no cause was found underwent electromyography (EMG). In 64 cases (85.3%) EMG showed changes suggestive of spasmophilia. The symptoms observed were those already described in this condition. The specific clinical signs of spasmophilia were often elicited with a positive Chvostek sign in 20 out of 30 cases (73.3%). Radiological, echocardiographical and haemodynamic studies underlined the hyperkinetic state of the left ventricle. Biochemical investigations showed a high incidence of low erythrocytic magnesium levels. Chest pain suggestive of angina pectoris, mitral valve prolapse and spasmophilia are frequently associated. The role of the low erythrocyte magnesium on left ventricular hyperkinesis and the production of MVP is discussed.

Adult↗
PubMed1979

Transient left anterior hemiblock during angina pectoris: coronarographic aspects and clinical significance.

The data of 6 patients in whom a left anterior hemiblock appeared in the course of angina pectoris attacks were reviewed. All 6 patients were found to fulfill the criteria for unstable angina. 1 patient who presented the features of Prinzmetal variant angina was included in this group. Coronary arteriography showed significant coronary artery disease in all 6 patients involving 3 vessels in 2 patients, 2 vessels in 1 and 1 vessel in 3. A severe lesion (70--100%) of the left anterior descending artery in the vicinity of the first perforator was demonstrated in every case. The 2 patients with 3-vessel disease were not operable and died 4 and 5 days after the hemodynamic study. These deaths were caused by myocardial infarction with cardiogenic shock in one case and intractable ventricular arrhythmias in the other case. 4 patients were operable and underwent aortocoronary saphenous bypass surgery. There were 2 operative deaths. The 2 survivors are asymptomatic 7 and 16 mth after surgery. This study suggest that transient left anterior hemiblock during an attack of angina pectoris may be a feature of impending myocardial infarction and may be indicative of a severe obstruction of the left anterior descending coronary artery.

Adult↗
PubMed1978

Pure left anterior hemiblock: hemodynamic and arteriographic aspects in patients with coronary artery disease.

The electrocardiographic pattern of pure (without bundle branch block) left anterior hemiblock was found in 20 (7.3%) out of 283 consecutive patients who showed significant coronary artery disease at coronary angiography. The clinical, hemodynamic and angiographic findings of these 20 patients are reported. 10 patients (50%) had the electrocardiographic features of old infarction. Pure left anterior hemiblock was associated with; (1) a significant lesion of the left anterior descending in all patients, (2) severe coronary artery disease (it affected 2.5 vessels per patient), (3) impairment of left ventricular contraction pattern in 14 patients (77%), 9 of whom had a ventricular aneurysm. Abnormal left axis deviation although with the features of left anterior hemiblock may be due to the conduction delay encountered by the impulse propagation through an ischemic or fibrotic anterosuperior wall.

Aged↗
PubMed1977

Effect of atenolol, a new cardioselective beta-blocker, on plasma renin activity in treatment of hypertension.

Atenolol, a cardioselective beta-blocking drug, was prescribed in doses of 100 mg b.i.d. in 23 patients with essential hypertension. At the end of the first month of treatment with Atenolol we found a significant fall in blood pressure, heart rate and plasma renin activity (P.R.A.). Besides, there existed a relationship between changes in diastolic blood pressure, in mean arterial pressure and initial plasma renin activity, and a relationship between changes in blood pressure and changes in P.R.A. It results from this finding that pretreatment P.R.A. is of predictive value of short-term efficacy of the beta-blocker. This correlation was borderline in 21 patients after a mean of 7 month treatment and could no be found for 12 cases after a mean of 10 month-treatment while the fall in P.R.A. was still significant. It therefore appears that--with reserve of the representativeness of the sample--quantitative relations between the antihypertensive effect of Atenonol and P.R.A. are no longer significant on long-term treatment.

Adult↗
PubMed1977

[The mitral apparatus and surgery of sub-valvular aortic stenosis].

The authors present three eases of subvalvular aortic stenosis caused by an abnormality of the mitral valve mechanism which required placement of a prosthetic valve. They describe the types of mitral valve abnormality which are reported in the literature to have caused obstruction to the aortic outflow tract. They analyse the criteria for diagnosis of this condition, and the surgical treatment. The placement of a prosthetic mitral valve does not always remove the obstruction to the aortic outflow, especially if there is an abnormality in the position of the mitral ring.

Adolescent↗
PubMed1977

[Abnormalities of insulin secretion in coronary patients. Apropos of 67 cases].

The curve of blood insulin levels recorded during the oral provoked hypoglycaemia test (OPHG) was studied in 67 proven coronary patients. None of the curves obtained was normal. The abnormalities found in this way are of two types: either a hypoinsulinaemic response, with a high non-retarded peak (type 1) or a high retarded peak (type 2), or else a hypoinsulinaemic response, with a flat curve (type 3) or a very small late peak (type 4). The possible role of these abnormalities of insulin secretion in the pathogenesis of atheroma is discussed. The correlations between age, sex, obesity, hypertriglyceridaemia, and the OPHG curve are investigated. The preliminary results of a test in which insulin levels are monitored after intravenous provoked hypoglycaemia, followed by tolbutamide, are reported.

Adult↗
PubMed1976

[Treatment of rhythm disorders by fenoxedil hydrochloride].

Fenoxedil chlorhydrate (FC), which is used as a treatment for cerebral circulatory failure and peripheral vascular disease, has been given to 100 patients with a cardiac arrhythmia: atrial fibrillation (78 cases), atrial flutter (4 cases), atrial tachysystole (2 cases), ventricular extrasystoles (12 cases), and supraventricular extrasystoles (4 cases). FC has been prescribed alone, or as a complement to current anticoagulant or digitalis treatment; combination with prenylamine, amiodarone, dysopyramide or a drug of the quinidine group must always be avoided, and the potassium level checked and corrected if necessary before treatment. In 78 cases of atrial fibrillation, the authors found that sinus rhythm was restored in 58 (74.4%); four cases of flutter were restored, and one case out of two of atrial tachycardia. In case of supraventricular and ventricular extrasystoles the results are less clear, and merit a further study with a larger number of cases. The electrocardiographic disorders encountered in this series have been evaluated: lenghthening of the QT interval, disorders of atrioventricular conduction, sinus inhibition. They were either produced by or aggravated by the FC. No cases of axis deviation were encountered. The authors make mention of the complications observed by other authors, but draw a distinction between the prescription of FC in cases of cerebral vascular insufficiency, without previous knowledge of the exact cardiac status of the patient (otherwise there is a risk of severe accidents), and the use of FC in cases of arrhythmia which have undergone full assessment before the drug is used. According to this study, FC appears to be a very effective anti-arrhythmic agent, but its use demands very rigorous clinical and electrocardiographic supervision.

Anti-Arrhythmia Agents↗
PubMed1976

[Congenital bundle-of-his focal tachycardias. Cooperative study of 7 cases].

The authors described seven cases of supraventricular tachycardia with atrio-ventricular dissociation, associated with the activity of an automatic focus in the bundle of His. These tachycardias, which appear at birth or are discovered at a very young age, appear to be congenital and sometimes familial, and are always isolated, having no associated cardiac abnormality. They give rise to cardiac failure, which is more marked when the rate is high (180-260/mn) and particularly resistant to treatment. The most effective form of treatment is amiodarone, almost always used in combination with digitalis. The anatomical abnormality, which was studied in the first case, is a contricting fibrosis around the main trunk of the bundle of His, and the appearances are reminiscent of those found in conditions of congenital atrio-ventricular block.

Amiodarone↗
PubMed1976

[Atrioventricular "sequential" stimulation by implantable "bifocal" stimulator].

The "bifocal pacemaker achieves a sequential" stimulation which reproduces the physiological atrio-ventricular sequence. This type of stimulation has the advantages of atrial stimulation without the disadvantages of being inefficient when an atrio-ventricular block exists or supervenes. The pacemaker was used by the endocavity route in 12 patients. The indications included a disease of the sinus node (8 cases), supra-ventricular arrhythmias associated to conduction disorders (3 cases) and a cardiomyopathy with conduction disorders (1 case). The preliminary results were appraised after two to twenty four months. One displacement of the ventricular electrode was noted. On the other hand no displacement of the atrial electrode was reported. One battery was worn out after 19 months. The "bifocal" pacemaker was efficient in the treatment of symptoms which justified its implantation. Or particular interest were the results obtained in patients with no supraventricular arrhythmias. This pacemaker may be of use: 1) in the disease of the sinus node, in particular in the tachycardia-bradycardia syndrome; 2) in supraventricular arrhythmias associated to paroxystic conduction disorders; 3)in patients with an alteration of the myocardial function and for whom the atrial contribution to cardiac output is essential.

Aged↗
PubMed1976

["Habitual" left branch block alternating with 2 "disguised" bracnch block].

Two cases of alternating left bundle branch block and "masquerading block" (with left bundle branch morphology in the stnadard leads and right bundle branch block morphology in the precordial leads) were studied by serial tracings and his bundle electrocardiography. In case 1 "the masquerading" block was associated with a first degree AV block related to a prolongation of HV interval. This case is to our knowledge the first cas of alternating bundle branch block in which his bundle activity was recorded in man. In case 2, the patient had atrial fibrilation and His bundle recordings were performed while differents degrees of left bundle branch block were present: The mechanism of the alternation and the concept of "masquerading" block are discussed. It is suggested that this type of block represents a right bundle branch block associated with severe lesions of the "left system".

Aged↗
PubMed1975

[Sinus arrest: severe complication of intravenous lidocaine].

Sinus arrest occured after intravenous administration of Lidocaine in therapeutic disage in a patient with coronary artery disease and sinus node disease. This complication of Lidocaine, though rare (this case is the fourth of the literature), induces to use this drug carefully in patients with sinus node disease. Temporary pacing is recommended if Lidocaine must be used in this group of patients.

Aged↗