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Biomedical subjects

H Bricaud

Publications and source records attributed to H Bricaud.

At least 19 recordsLinked to original sources
PubMed1992

Biological risk factors for sudden death in patients with coronary artery disease and without heart failure.

In a study of biological risk factors for sudden death in patients with coronary artery disease, 320 patients were, prospectively, recruited and followed-up over two years. None of the patients had heart failure or recent myocardial infarction. The following variables were recorded: previous acute myocardial infarction, hypertension, smoking habits, ventricular arrhythmia; the angiographic variables included: left ventricular ejection fraction, Jenkins' and mean atherosclerotic scores; lipid profile: cholesterol, triglycerides, high density lipoprotein cholesterol, low density lipoprotein cholesterol, apolipoproteins Al and B; hemostatic profile: fibrinogen, fibrinopeptide A, antithrombin III, factor VIII antigen, factor VIII coagulant, protein C, plasminogen, alpha 2-antiplasmin, euglobulin clot lysis time and tissue plasminogen activator before and after venous occlusion, tissue plasminogen activator inhibitor, platelet factor 4, beta-thromboglobulin. During the follow-up period, 12 of the patients died suddenly. In these patients, ejection fraction was lower: 49 +/- 16% versus 61 +/- 14% for the other patients (P less than 0.02), fibrinogen higher: 3.9 +/- 0.8 g/l versus 3.5 +/- 0.8 for the living patients (P less than 0.05) and protein C lower: 89 +/- 39% versus 111 +/- 39% (P = 0.06) for the other patients. In multivariate analysis: lower ejection fraction (P less than 0.008), older age (P less than 0.03) and lower protein C (P less than 0.01) were correlated with sudden death. Among the patients with coronary artery disease, the raised fibrinogen and the decreased protein C appeared to be risk factors for sudden cardiac death. These alterations reflected a prothrombotic state which might increase the ischemic risk, due to an acute thrombosis, leading to the fatal ventricular arrhythmia. Determination of these hemostatic variables might be a useful adjunct for assessment of the vital prognosis of patients with coronary artery disease, especially the risk of sudden death in addition to other known clinical, electrocardiographic, hemodynamic risk factors. This would also guide both the instigation of complementary investigations and appropriate therapy in such high risk group of patients.

Aged↗
PubMed1992

Evaluation of plasmatic leucocyte elastase levels in coronary artery disease.

Leucocyte elastase may be involved in the structural modification observed in the atherosclerotic process. Therefore, we tested the usefulness of leucocyte elastase plasma level determination as a marker for atherosclerosis. Plasma levels of elastase were determined by ELISA in 100 consecutive patients (mean age 56 +/- 9.8 years) admitted to hospital for coronary angiographic investigation of chest pain. Eighty-seven patients had evidence of atherosclerosis, and 13 patients had normal coronary vessels. No significant difference in leucocyte elastase was found between the 2 groups, nor was there any relationship between elastase levels and the severity of atherosclerosis. However, relationships between plasma leucocyte elastase levels and various lipid fractions (Apo AI, LDL) and daily tobacco consumption were found. Leucocyte elastase may thus play a role not only by direct modification of the vessel wall, but also indirectly via risk factors such as dyslipoproteinemia and leucocyte toxicity.

Coronary Angiography↗
PubMed1991

[Cardiac lesions in Takayasu's disease. A case with initial pericarditis and tamponade].

The authors report the case of 21-year old female patient with a particular form of Takayasu's disease remarkable for its initial presentation and its cardiac and coronary lesions. The disease began with miscarriage at the 5th months of pregnancy, followed by acute pericarditis with tamponade. Subsequently, lesions of the aortic and mitral valves developed, while the myocardium became involved with left ventricular dilatation and hypokinesia confirmed by echocardiography and cineangiography. Coronary arteriography revealed large coronary aneurysms which are exceptional in this disease. This case prompted the authors to discuss the various cardiac lesions and the relationship of Takayasu's disease with pregnancy.

Adult↗
PubMed1979

Pacing-induced alternate Wenckebach periods: incidence and clinical significance.

Alternate Wenckebach periods have been defined as episodes of 2:1 atrioventricular (AV) block in which conducted P waves exhibit progressive PR prolongation until two or three successively blocked P waves. Ocurrence of this phenomenon during atrial pacing has been established. Thirty-six patients were studied and right atrial pacing was achieved at increasing rates up to 350 beats/min in order to induce alternate Wenckebach periods. His bundle recordings were obtained in every patient. The patients were subdivided into three groups according to the AV nodal conduction time (AH interval): normal AH (75-130 ms) was present in 17 patients, short AH (70 ms) in 13 patients and prolonged AH (130 ms) in eight patients. Alternate Wenckebach periods were observed in 29 patients (80.5%). In every patient alternate Wenckebach periods occurred at the AV node level. Atrial pacing failed to induce alternate Wenckebach periods in seven patients, six of whom belonged to the short AH group. In four patients 3:1 block never appeared because of block at the atrial level. Two patients presented 2:1 and 3:1 infrahissian block without significant AH prolongation. The remaining patient developed atrial fibrillation. Alternate Wenckebach periods were observed in six of nine patients after intravenous atropine. This study suggests: 1. pacing-induced alternate Wenckebach periods at the AV node level are a physiologic phenomenon; and 2. total or partial bypass (or accelerated AV conduction) atrial refractoriness or vulnerability or block at a lower level may prevent its occurrence.

Adult↗
PubMed1979

Long-term results of permanent atrioventricular sequential demand pacing.

Pervenous atrioventricular sequential demand pacemakers (AVSDPs) were implanted in 18 patients using an atrial electrode positioned in the right atrial appendage and a ventricular electrode positioned at the apex of the right ventricle. The indications included 13 patients with the sick sinus syndrome (72%), five of whom had the tachycardia-bradycardia syndrome, three with paroxysmal supraventricular tachycardia, one with cardiomyopathy and one with carotid sinus syncope. The follow-up ranged from 6 to 38 months, with a mean of 19.4 months (a total of 350 pacing months). Seventeen patients (94%) are asymptomatic. One patient had persistent episodes of paroxysmal supraventricular tachycardia. In the remaining patients with tachyarrhythmia, pacing alone (three patients) or in combination with antiarrhythmic drugs (four patients) controlled the tachyarrhythmia. There was one displacement of the atrial electrode (5.5%). Extrusion of the pacer occurred in three patients. It is concluded from this experience that AV sequential pacing is an effective technique and may be useful in patients with sick sinus syndrome, in patients with tachyarrhythmia and/or patients with poor myocardial function. However, continued research is needed to prolong battery life and to reduce the size of the pacemaker.

Aged↗
PubMed1979

[Effect of nitrate derivatives on the contractility and relaxation of papillary muscle in hypoxia and reoxygenation].

The direct action of nitrate derivatives on myocardial contractility is not fully understood. The effects of Glyceryl Trinitrate (1 mM/L.) and Sodium Nitro prussiate (3 X 10(-5) M/L.) on papillary muscle were studied during 30 minutes hypoxia followed by 60 minutes reoxygenation: Both conditions were analysed every 5 minutes: 1. Contractility was assessed by maximal shortening velocity with no load (Vmax), maximal isometric force (PF), number of active cross-bridges and peak time (TPF), a characteristic of the period of activity. 2. Relaxation was assessed by the relaxation velocity (V relax) and the 1/2 relaxation time (THR). The two nitrate derivatives had the same effects: during anoxia, a notable reduction of the maximal force was observed; myocardial depression continued during the first 15 minutes of reoxygenation. After the 30th minute of investigation all parameters increased significantly (107-110 p. 100, p less than 0,01); TPF and THR returned to normal. A positive inotropic effect and improvement of the relaxation phase were observed at the end of reoxygenation. This effect is not attributed to improved segmental performance especially as it occurred at dosages close to those used in therapeutics.

Animals↗
PubMed1979

[Paroxysmal supraventricular tachycardia with complete atrio-ventricular block or dissociation].

Recent studies have shown the high incidence of concealed Bundles of Kent in the reentry circuits of paroxysmal supraventricular tachycardia. Arguments in favour of the nodal or junctional level of reentry were observed in supraventricular tachycardia with complete atrioventricular dissociation. Two such cases under went electrophysiological investigation. In the first case, tachycardia was terminated by a complete infrahisian block. However, during atrioventricular dissociation, tachycardia could be initiated by a single atrial stimulus after an increased nodal conduction time and terminated by a single atrial stimulus or cardiac message. In the second case the supraventricular tachycardia presented with complete atrioventricular dissociation due to a retrograde ventriculo-atrial block. Atrial stimulation at progressively higher rates and premature atrial extra stimuli initiated the tachycardia but could not terminate it, so confirming the non-participation of the atrium in the reentry circuit. These two cases suggest that the ventricle (case I) and the atrium (case II) are not indispensable links in junctional or nodal reentry circuits. Case II was suggestive of a common initial pathway developing retrograde unidirectional block during tachycardia.

Aged↗
PubMed1979

[Wolff-Parkinson-White syndrome. Correlation between the results of electrophysiological investigation and exercise tolerance testing on the electrical aspect of preexcitation].

Fourteen patients with permanent electrocardiographical features of the Wolff-Parkison-White syndrome in sinus rhythm referred for electrophysiological investigation also underwent maximal exercise tolerance tests. The working hypothesis was that in patients with the Wolff-Parkinson-White syndrome with accessory pathways of longer effective refractory periods than the normal pathway (group I) the delta wave should disappear on exercise, whilst in patients with accessory pathways with shorter refractory periods than the normal pathway (group II) the delta wave should persist. Of the 9 patients in group I,the delta wave regressed in 8 and persisted in 1 patient; of the 5 patients in group II, the delta wave persisted in 4 of them. Three patients had attacks of tachycardia during or just after the exercise tolerance test. These results suggest that the exercise tolerance test may help in the identification of patients with accessory pathways with long refractory periods, less susceptible to rapid ventricular rhythms should atrial fibrillation occur, and therefore with better prognoses.

Adolescent↗
PubMed1978

Serum elastase inhibitors in cardio-vascular diseases.

Serum elastase inhibiting capacity was measured in three groups: 150 control subjects, 38 hospitalized children without cardiovacular diseases and 202 hospitalized patients suffering from cardiovascular diseases. The values obtained were 53% in control adult subjects and 79% (range 45--90%) in the hospitalized patient groups. The highest levels were recorded at the acute phase of myocardial infarction. The levels of alpha 1-antitrypsin (alpha1-AT) and alpha 2-macroglobulin (alpha2-M) were determined by radial immunodiffusion technique for various levels of inhibitory power. No correlation was found between the inhibitory power levels and the alpha1-AT and alpha2-M levels. This study suggests that other proteins may intervene in the inhibition process of elastolysis.

Adolescent↗
PubMed1978

[Isolated left anterior hemiblock during attacks of angina pectoris].

The clinical significance and mechanism for changes in the axis of the QRS complex during attacks of angina pectoris (excluding cases of Prinzmetal's angina) are unknown. Previous work has suggested that left anterior hemiblock under these circumstances is a sign of unstable angina indicating a lesion in the anterior descending artery. Two cases with left anterior hemiblock associated with frequent attacks of angina have been the subject of careful study. In case one, atrial stimulation tests showed that the left axis deviation was not related to tachycardia. It only occurred when atrial stimulation was carried out for long enough to induce myocardial ischaemia as witnessed by precordial pain and disorders of repolarisation. In case two, the left anterior hemiblock came on at first at the same time as the attacks of angina, and then became permanent. Bypass graft of the anterior descending artery restored the QRS axis to normal, and corrected the repolarisation disorders which were of ischaemic origin. These findings argue in favour of an ischaemic origin of this conduction defect. Unlike ischaemia of the left anterosuperior subbranch, anterior left hemiblock is indicative of extensive ischaemia of the anterior wall of the left ventricle relative to an obstruction in the anterior descending artery or in the main trunk of the left coronary artery.

Aged↗
PubMed1978

[Hemolysis and platelet function in patients with prosthetic heart valves. Changes during exercise and with propranolol].

10 control subjects and 27 patients with prosthetic valves (15 with Björk aortic valves, 6 with mitral prostheses, 4 with aortic and mitral valves, 1 with a Björk mitral and a Starr aortic valve, and 1 with a Beall mitral valve) underwent, at intervals of 24 hours, two maximal exercise tests, initially without (day J) and subsequently with (day J + 2) propranolol in a dose of 80 mg/24 h, haemolysis and platelet function being assessed immediately before and immediately after each test. Exercise tolerance was not altered by propranolol in this dose, provided the heart size was not more than 1500 ml. Haemolysis, as assessed by the level of lactic dehydrogenase (LDH1) was increased by exercise, especially in the aortic prosthesis cases in which the LDH1 was increased by 21.6% (p less than 0.025). The increase was less marked under propranolol treatment, when it was 12.3% (p less than 0.05). Propranolol did not correct the platelet clumping caused by the prosthetic mitral valves, but did decrease platelet stickiness on exercise in the patients with prostheses (delta = -11.7%; p less than 0.05). Propranolol can not therefore be recommended for increased haemolysis if there is no demonstrable dysfunction of the prosthetic valve. Neither would we advise its use at present with the aim of reducing thrombotic accidents.

Adult↗
PubMed1978

[Hypertensive cardiopathy. Study of cardiac performance].

Twenty-two hypertensive patients with normal coronary arteriograms underwent a complete study of left ventricular performance. The patients were classified into three groups according to the findings on X-ray and ECG investigation: group I--ECG normal, X-ray normal (6 cases); group II--ECG showed left atrial hypertrophy, X-ray normal (7 cases); group III-ECG showed left ventricular hypertrophy, X-ray showed cardiac dilatation (9 cases). The results of this study were as follows:--cardiac ouptut was lowered in groups II and III;--end-diastolic volume was lowered in group II and raised in group III;--LVEDP was raised in groups II and III;--V max and VEC max were lower in groups II and III than in group I;--left ventricular compliance was diminished in groups I and II. Myocardial rigidity of the left ventricle was similar in the three groups. Hypertensive heart disease is therefore characterised by early changes in compliance of the left ventricle. These are associated with geometrical changes in the ventricle: disturbance of the volume/mass ratio of the left ventricle. These findings have therapeutic implications for the importance of beta-blockers.

Adult↗
PubMed1977

Fibrous long spacing collagen in aortic explants of normal rabbit cultured in hypercholesterolemic serum.

Aortic tissues consisting of all three tunics were removed from normal adult rabbits and cultured in a semisynthetic gelosed medium supplemented by 10% serum obtained either from normal or hypercholesterolemic rabbits. Fibrillar cross-striated aggregates appeared with a high frequency (50%) in the extracellular space of explants cultured from four to eight days in medium supplemented by serum from hypercholesterolemic rabbits, but did not appear in explants cultured in serum from control animals (3%). The electron-dense segment was ruthenium red positive and digested by testicular hyaluronidase. The electron-lucent segment, composed of ruthenium red negative thin filaments, was not modified after hyaluronidase treatment but was strongly digested after collagenase treatment. It is believed that this material was fibrous long spacing collagen synthetized under culture conditions, as shown after tritiated proline incorporation.

Animals↗
PubMed1977

Effects of hypercholesterolaemic serum on aortic explants from normal rats.

Aortic explants obtained from normal adult rats and composed of all 3 tunics were cultured in a semi-synthetic gelosed medium supplemented by 10% serum. Explants cultured with normocholesterolaemic serum kept their in vivo characteristics for more than 12 days at electron microscope and histometabolic levels. However, explants showed considerable differences when cultured in a medium with hypercholesterolaemic serum. Cell proliferation in the tunica media and enhanced synthesis of macromolecular components of the extracellular matrix were observed. These laterations occurring inside the explants, which had kept all their tissular relationships, suggest that this culture system may be valuable for further studies on atherosclerotic processes.

Animals↗
PubMed1977

[Hemodynamic effects of intravenous amiodarone in humans].

The haemodynamic action of I-V Cordarone have been studied in 20 subjects over a 15 minute period. Over the 15 minute period we studied variations in left pulmonary and ventricular pressures, in cardiac output, and in the paramaters of contraction VEC max, V max and Taylor's index. At a dose of 5 mg/kg there is a fall in peripheral resistance (1274 +/- 232 to 915 dynes/s/cm-5), and the measurements of contraction hardly vary. At a dose of 10 mg/kg, after an initial increase in output and a fall in peripheral resistance there occurs, after 4 minutes, an increase in left ventricular end-diastolic pressure (from 6 +/- 2 to 13 +/- 4 mmHg, P less than 0.01), and a lowering of contractility (VEC max reduced from 49.7 +/- 12.4 to 27.1 +/- 3.8, P less than 0.001). We have shown that the first phase of this response is due to the solvent (Tween 80), while the fall in contractility is due to the amiodarone. Doses above 10 mg/kg must be used with care, and only if there is no evidence of impaired cardiac function.

Amiodarone↗
PubMed1976

[Influence of a lathyric agent and of hypercholesterolemic serum on cell cultures of fetal rabbit aorta].

Cell cultures of foetal rabbit aorta are cultivated with a lathyric agent (beta-amino-propio-nitrile) or with an hypercholesterolemic serum; if morphological features, in these two cases, correspond with modifications observed, in vivo, when adult rabbits are respectively submitted to the same treatment, enzymatic activities of collagen metabolism vary in opposite way. Therefore, the influence of different parameters to be studied on vascular cell functions become easier.

Aminopropionitrile↗