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Biomedical subjects

H Bricaud

Publications and source records attributed to H Bricaud.

At least 127 records · Page 7Linked to original sources
PubMed1980

Alternate ventriculoatrial Wenckebach conduction.

Three cases are presented showing retrograde alternate Wenckebach periods. Retrograde alternate Wenckebach periods were defined as 2:1 ventriculoatrial (VA) block in which the conducted beats showed progressive prolongation of conduction (VA) time. The sequence terminates with two or three successively blocked ventricular beats. In one of the three cases the level of block was identified as being in the atrioventricular (AV) node. In the other two the level of block could not be clearly identified. This report provides further evidence for the concept of multilevel block within the AV node. Retrograde alternate Wenckebach periods may explain some instances of variation of atrial depolarization intervals during episodes of ventricular tachycardia and may be clinically significant.

Aged↗
PubMed1980

Isolation and biological properties of a rabbit antibody to porcine pancreatic elastase and its use as ligand for elastase purification.

By affinity chromatography on porcine pancreatic elastase bound to Sepharose an anti-elastase antibody was isolated from the serum of rabbits who had been injected with porcine pancreatic elastase and fed a light cholesterol diet. The protein (molecular weight 150,000 daltons) was recovered with both a high degree of purity and intact biological properties. It specifically inhibited elastolysis by a mechanism distinct from that known elastase inhibition by alpha 1 antiprotease and alpha 2 macroglobulin. Results of this study indicate that inhibition is due to an IgG antibody to the porcine elastase. The antigen-antibody reaction appears to involve the active site of elastase. The isolated IgG in turn binds to activated Sepharose and the resulting immunoadsorbent system allows purification of pancreatic elastase by affinity chromatography.

Animals↗
PubMed1980

[Changes in left ventricular filling in obstructive cardiomyopathies during long term beta blockade].

Left ventricular filling was studied by echocardiography and cineangiography in 37 patients with hypertrophic cardiomyopathy with obstruction before and during long-term oral beta blockade (166 +/- 61 mg propranolol for 15.6 +/- 21 months on average) in order to determine the mechanism of symptomatic improvement in these patients. This study confirmed that clinical improvement is related to a great degree to the improvement in the parameters of left ventricular filling. In addition, two groups of patients may be identified: the "reactors", that is to say the patients who remained or became asymptomatic, characterised by a significant improvement in the indices of left ventricular filling (maximum filling velocity p < 0.01, duration of rapid filling p < 0.05, left ventricular compliance--volumic kGaasch p < 0.001, parietal ks Mirsky p < 0.01). The "non-reactors" were characterised by very poor indices of left ventricular filling. These abnormalities are principally related to severe and irreversible changes in left ventricular and mitral valve morphology.

Adrenergic beta-Antagonists↗
PubMed1980

[Ventricular tachycardia. A possible complication of intravenous atropine in the coronary patient].

Ventricular tachycardia occurred with chest pain in a 64 year old man with coronary artery disease after an intravenous injection of atropine. The particular feature of this case as compared to the other 8 reported cases is the restoration of sinus rhythm after a passage of accelerated idioventricular rhythm by the administration of oxygen and nitroglycerin. The increased oxygen consumption and myocardial ischaemia due to the tachycardia seem to be the factors responsible for these ventricular arrhythmias. Such cases, though rare, incite caution in the administration of atropine to patients with coronary artery disease.

Atropine↗
PubMed1980

[Atrial myxoma. Changes in clinical and paraclinical data. Apropos of 17 cases].

The clinical data and presenting signs of 17 cases of atrial myxoma (14 left atrial, 3 right atrial myxomas) were analysed. The aim of the study was to assess changes in the presenting features since the introduction of non-invasive methods of cardiovascular investigation. Two groups of patients were identified according to whether the tumour has been diagnosed before (Group A) or after (Group B) the advent of echocardiography. The diagnosis of cardiac tumour, especially myxoma, has become easier with echocardiography and radio-isotope techniques. The presentation of myxoma, recognised earlier, has changed; the features of advanced valvular disease with resistant heart failure are no longer seen. Variable, atypical clinical signs are now encountered (syncope, pyrexia of uknknown origin, transient ischaemic attacks). The average delay between the first sign and diagnosis was 30 +/- 32 months in Group A, compared to 4,6 +/- 6,5 months in Group B (p < 0, 005). Of the 7 patients in Group B, three had normal cardiac auscultation, and normal ECG, and four had normal ESRs. The diagnosis of myxoma should be considered at the least doubt and an echocardiographic examination, preferably with 2-dimensional echo should be requested. It not only allows positive diagnosis but also orientates the patient to surgery without further investigation.

Adolescent↗
PubMed1980

[Wolff-Parkinson-White syndrome after 50 yars of age. Clinical and electrophysiological data].

The Wolff-Parkinson-White syndrome is usually observed in young people and is much rarer in patients over 50 years old. This fact may be explained by the demise of a certain number of patients before the age of 50 and/or a change in the clinical features of the syndrome with age and/or of the electrophysiological properties of the normal and accessory conduction pathways. To test the latter hypothesis, the clinical and electrophysiological data of 15 patients over 50 years old with the Wolff-Parkinson-White syndrome (Group I) were compared with that of 10 patients under 30 years old with the same syndrome (Group II). The same protocol of electrophysiological investigation was used in both groups of patients. The results showed a significant difference (p < 0.001) between the two groups in the incidence of associated cardiac disease. This was more common in Group I (1 4 out of 15 patients) than in Group II (2 out of 10 patients). The cardiothoracic ratio was significantly higher in Group I (p < 0.01). The two groups also differed in the age at which tachycardia first occured. 9 out of 11 patients in Group I only had symptoms after thirty years. On the other hand, there was no significant difference in the types of tachycardia and the frequency of attacks. There was no significant difference in QRS, PR, AH, HV intervals, in the ventriculo-atrial conduction time and the effective refractory periods of the atrium, right ventricle or atrio-ventricular node. There was no significant difference in the anterograde and retrograde refractory periods of the accessory pathways between the two groups. Reciprocating tachycardia, initiated by electrical stimulation in 7 patients in Group I and 6 patients in Group II, was conducted anterogradely to the ventricles through the normal pathway and retrogradely to the atria through the the accessory pathway. This study suggest that age-related changes in the electrophysiological properties of the accessory are not an important prognostic factor in the Wolff-Parkinson-White syndrome.

Adolescent↗
PubMed1980

[Pharmacokinetics of anti-arrhythmics. 2. Clinical applications].

The clinical usage of antiarrhythmic drugs may pose problems which could be solved by the direct application of the basic principles of pharmacokinetics. These problems involve the calculation of intravenous infusion rates and or oral dosages. Examples are provided by the rate of initial infusion of lignocaine in order to obtain a concentration within the therapeutic range, the eventual adjustment of this rate of infusion and the calculation of a loading dose. As regards the oral route, the calculation of the doses of procainamide is taken as an example. The estimation of the serum procainamide is a method for determining whether the dose should be increased or whether the drug is ineffective when no clinical result is observed. The pharmacokinetics of the main antiarrhythmic drugs are reviewed; procainamide, quinidine, propanolol, phenytoin, disopyramide. The therapeutic dose, clearance, extraction coefficient, bioavailability and half-life are the object of particular study. The fractioning of the dose and the total dose in a 24 hour period depend on these factors. The effects of cardiac, renal and hepatic failure on the clearance of each drug are recalled. These pharmacokinetic principles help the clinician not only in the prescription of an antiarrhythmic drug but also in deciding on the indications for drug serum concentration, estimations which are particularly useful in some difficult clinical situations, and in interpreting the results.

Administration, Oral↗
PubMed1980

[Auriculo-Hisian conduction of patients with bundle branch block. Clinical significance].

The clinical and electrophysiological data in 52 consecutive patients with bundle branch block and followed-up for an average period of 20.8 +/- 10.4 months was reviewed. The patients were divided into two groups: Group A with normal AH intervals (36 patients) and Group B with prolonged AH intervals (16 patients). These two groups differed in age, the average being higher in Group B (p < 0.05), in history of syncope (more common in Group A: p < 0.01) and in the duration of PR interval (p < 0.05). On electrophysiological investigation the Wenckebach point was lower in Group B (118 +/- 29 ms) than in Group A (160 +/- 33) (p < 0.001). The effective right atrial refractory period was significantly longer in Group B (321 +/- 111 ms) than in Group A (246 +/- 59 ms) (p < 0.05). The effective refractory period of the atrioventricular node was also significantly longer in Group B (492 +/- 190 ms) than in Group A (333 +/- 125 ms (p < 0.05). On the other hand, there was no significant difference in the HV interval or in the number of patients managed by permanent pacing.

Atrioventricular Node↗
PubMed1980

[Biosynthesis in vitro of extracellular matrix in arteriosclerotic areas of rabbit aortas. Autoradiographic study of tritiated proline incorporation kinetics].

The elaboration of the extracellular matrix was investigated by radio-autoradiography after incubation of aortic strips, isolated from thoracic aortas of healthy and atherosclerotic rabbits, with tritium labeled proline. Time course experiments indicated that there was a delay of about one hour before significant amounts (25%) of tritiated macromolecules were released from the intact smooth muscle cells. On the contrary, both, the level of incorporation and the rate of excretion of macromolecular components by modified smooth muscle cells of the atherosclerotic area from injured strips were increased. The results indicate that, under the conditions of incubation in vitro, the modified smooth muscle cells of atherosclerotic plaque exhibit a particular behaviour for both, quantitative and qualitative features of macro-molecular synthesis of the extracellular matrix.

Animals↗
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↗