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Biomedical subjects

J F Leclercq

Publications and source records attributed to J F Leclercq.

At least 19 recordsLinked to original sources
PubMed1979

Sustained intra-atrial reentrant tachycardia. Electrophysiologic study of 20 cases.

Twenty cases of sustained tachycardia due to intra-atrial reentry were investigated in patients aged 17 to 80 years (mean 47). The average frequency of the tachycardia was 128.6/min (extremes 95 and 180). Three modes of onset of the tachycardia were observed: atrial extra-stimulus (19 times), progressively accelerated atrial pacing (9 times) and atrial escape beat (10 times). The tachycardia was stopped in all cases by a premature stimulation. When spontaneous, the termination was either sudden (10 times) or preceded by a progressive slowing (9 times) or an alternating phenomenon of long-short cycle (13 times). Precise atrial mapping allowed to localize the first atrial depolarization less frequently in the sinus node area (1 case) than in the mean right atrium (21 cases), the low right atrium (2 cases), the interatrial septum (2 cases), and the left atrium (4 cases). The macroscopic size of the reentry circuit was demonstrated in only 3 cases. A junctional reentry was accurately ruled out in all cases thanks to the existence of a second or third-degree AV or VA black, or by studying the sequence of retrograde atrial activation. A true junctional reciprocating tachycardia was associated with the intra-atrial reentry in 2 cases.

Adolescent↗
PubMed1979

Multilevel block in the atrioventricular node during atrial tachycardia and flutter alternating with Wenckebach phenomenon.

The electrocardiograms of 100 patients with rapid and regular PP intervals during atrial arrhythmias (because of atrial tachycardia or flutter, or pacing) were examined for periods of irregular atrioventricular conduction. This irregular conduction corresponds to an alternating Wenckebach phenomenon, of a type that can be determined from simple rules. The different types of conduction encountered in different patients and the changes seen in the same patient suggest that the atrioventricular node functions physiologically with 3 levels of sequential block. The different prevalence of the 2 types of alternating Wenckebach block may reflect functional differences at the level of the atrioventricular node.

Atrial Flutter↗
PubMed1979

[Intracorporeal cardiac pacemakers for refractory tachycardia (excluding atrial disease). Apropos of 18 cases].

The treatment of paroxysmal tachycardia by the use of permanent pacing to prevent or terminate attacks is discussed. The series comprises 18 patients with follow-up periods ranging from 1 to 12 years. In 6 cases the indication for pacing was atrial tachy-arrythmias favourised by bradycardia (5 of whom had vagally- induced atrial arrythmias). The atrial pacemaker successfully prevented attacks in 4 out of 6 cases. Three cases of chronic reciprocating tachycardia were successfully treated by simultaneous atrial and ventricular pacing or using sequential pacing with a very short P-R interval. Eight cases of paroxysmal orthodromic reciprocating tachycardia in the WPW syndrome were paced: in 5 cases pacing was employed to terminate attacks by atrial (3 cases) or ventricular (2 cases) stimulation, in the other 3 cases pacing was used to prevent the bradycardia which favourised the initiation of tachycardia. Good results were obtained in all 8 cases. Ventricular stimulation was used to terminate attacks in one patient with refractory ventricular tachycardia but the patient had a sudden death probably caused by the pacemaker. The place of these different pacing techniques with respect to medical treatment and specialised arrhythmia surgery is discussed.

Heart↗
PubMed1979

[Multicenter epidemiological survey of primary myocardiopathies. Apropos of 380 cases].

A retrospective study of adult congestive cardiomyopathy was carried out; the admission criteria being heart failure with cardiomegaly after the exclusion of known causes of heart failure. Coronary artery disease was excluded by forming two sub groups, one with proven normal coronary arteries at angiography or autopsy and the other with only assumedly normal coronary arteries. The results concern the study of the incidence of this disease which has been regularly seen over the last 10 years in departments with a large number of referrals of cardiomyopathy. --Professional factors are analysed to see if there is a higher incidence amongst the working classes. --Other factors are analysed by comparison with three control groups: normal, coronary and valvular disease, and diabetes which may be a predisposing factor, but not the serum cholesterol which is decreased in these patients. There is a significant association with smoking and alcoholism and the main biological sign of the latter condition, macrocytosis. This is also found in both coronary sub groups. The isolation of this alcohol factor in the genesis of congestive cardiomyopathy implies the possibility of reversing or stabilising the myocardial damage after its withdrawal, so changing the severe diagnosis associated with this disease.

Adolescent↗
PubMed1979

[Quantitative evaluation of the efficacy of anti-arrhythmia agents in chronic ventricular arrhythmia].

The authors describe a computer system for the analysis of ventricular arrhythmias and its use in the evaluation of anti-arrhythmic drugs. Provided the arrhythmia is stable, this method allows an estimation of the onset and duration of action of the drug and gives guidelines for the choice of an appropriate drug regimen. Using this system, a comparison can be made between different drugs based on quantification of their efficacy.

Amiodarone↗
PubMed1979

Correlation between angiographic and ECG signs location in unstable angina.

The authors examine if the modifications of the ventricular repolarisation in patients with unstable angina have a value in localizing the site of the coronary stenoses. The relationship between ECG changes and angiographic abnormalities, as yet unrecognized, is studied in 200 patients. The subendocardial signs have little value in predicting the place of the narrowings, they often involve the lateral leads and join with diffused coronary lesions. Subepicardial ECG changes, however, have a good value for prediction: the involvement of inferior leads implies a right coronary stenosis, and that of septal leads a left anterior descending stenosis. The importance of a systematic recording of these ECG changes in unstable angina before performing coronary angiography is discussed. They should be able to specify the ischemic area of the myocardium and then help clinicians to decide when coronarography (and bypass surgery) is indicated.

Angina Pectoris↗
PubMed1979

[Technical characteristics of a new computerized system for quantitative evaluation of cardiac arrhythmias (author's transl)].

The ATREC system is designed to carry out at sixty times real time the quantitative evaluation of arrhythmias in 24 hour magnetic tape recordings. A preprocessing unit eliminates the low frequency waves (P and T) and artefacts, and furnishes the computer (Mitra 15/35, 16 K words of core) with information on R-R interval, QRS duration, regular or irregular rhythm, bradycardia or pauses, transient to sustained tachycardia, and ventricular fibrillation. Extrasystoles are analyzed in terms of enlargement, number, coupling interval, bi or trigeminy, doublets or salvos. Trends of mean and extreme cardiac rate, and R-R interval histograms, are also available. The system is also available for ECG real time monitoring of patients in coronary care units. The computer can analyze 8 ECG tracings simultaneously. The ATREC system provides an important aid in the quantification of arrhythmias and improves the evaluation of antiarrhythmic drugs efficacy.

Anti-Arrhythmia Agents↗
PubMed1978

[2 or 3 level blocks in the Tawara node during atrial tachycardia].

In atrial flutter (or paroxysmal atrial tachycardia), the ventricular response is dependant on the passage through 3 superposed zones of conduction in the Tawara node, the zone of decremential conduction being the central zone N. When the ventricular response is between half and a quarter of the atrial rate there are two possible explanations: type B alternate Wenckebach period (mobitz I block in the central zone N, 2/1 block at the nodo-ventricular junction) or type A alternate Wenckebach period (Mobitz I block in the central zone N and 2/1 block at the atrio-nodal junction). These two responses may alternate in the same patient depending on the drug therapy or vagal activity due to a phenomenon similar to the "GAP" phenomenon. Inexactitudes in the working out of the arithmetic formulae may easily be explained by a certain degree of concealed conduction of blocked activation in one zone or more rarely by hisian extrasystoles. Type A alternate Wenckebach periods are always easier to construct than type B. Perfect 3/1 atrial flutter can only be explained by a type B alternate Wenckebach period with a 3/2 period with a 3/2 period in the N zone and a 2/1 block in the NH zone. When the ventricular rhythm is permanently very slow or when the RR intervals are greater than four times the atrial cycle, 3 zones of block are usually at issue (the third being located in the inferior part of the node or superior part of the bundle of His). Examples of 5/1, 6/1 flutter are thereby analysed. Rapid atrial pacing after termination of the atrial arrhythmia allows a better analysis of its mechanism and the successive reproduction of conduction defects in each zone of block.

Atrioventricular Node↗
PubMed1978

[Biochemistry of myocardium taken at autopsy. Preliminary report].

The findings after biochemical analysis of heart muscle taken at autopsy are given in this preliminary communication. Human myosin is made up of two heavy sub-units and two light sub-units: it is similar to cardiac myosin found in other mammals, but is different in certain characteristics, particularly immunological ones. Tropomyosin is made up of two different sub-units. The normal human heart contains 1 mg of collagen and 130 microgram of desoxyribonucleic acid (DNA) per 100 mg of fresh tissue. The degree of cardiac hypertrophy correlates with the increase total DNA within the heart, and with the lowering of myofibrillary Ca2+ ATPase, the concentration in the collagen remaining unchanged providing there is no ischaemic heart disease. These techniques may be used to quantify several factors, such as the degree of sclerosis or the nuclear mass in ill-understood conditions such as the primary cardiomyopathies.

Actins↗
PubMed1978

[The atrial arrhythmia syndrome of vagal origin].

Having observed 18 cases, the authors describe a syndrome of recurrent paroxysmal atrial arrhythmia which was very homogeneous from the clinical and ECG point of view. It was usually found in middle aged males, with no demonstrable underlying heart disease, whose disorder of intra-atrial conduction occurred during sinus rhythm. The condition developed slowly over the course of years towards a maximum incidence of several short daily attacks of an arrhythmia which alternated between an atrial fibrillation and atrial flutter. Vagal overactivity is the precipitating cause of these attacks which are usually not completely nocturnal. The condition never progressed to sino-atrial block nor to permanent fibrillation. The beginning of each attack, often heralded by atrial coupling with a long enough interval to cause re-entry, is accompanied by slowing of the sinus rate down to the threshold level. The vagal effect of shortening the action potential and refractory period is recognised to be non-homogeneous in the atrial wall, and suggests a re-entry mechanism rather than hyper-excitability. This would explain the usual resistance of atrial arrhythmias of vagal origin to digitalis, beta blockers and quinidine. Amiodarone alone is usually effective because of the prolongation of the action potential which it causes. In 5 particularly resistant cases a good clinical result was obtained by the insertion of an atrial pacemaker with a fairly rapid rate.

Adrenergic beta-Antagonists↗
PubMed1977

[Biventricular massive infarction with rupture of a mitral papillary muscle and a tricuspid papillary muscle].

The authors report the case of a man of 62 who was admitted with a clinical and electrocardiographic picture of a posterior infarction which was very soon complicated by collapse and anuria. The findings on catheterisation of the right side of the heart were as expected. The cardiac index was very low, and the major abnormality was a type of adiastole with equal pressures in the right ventricle and the auricle of the right atrium. Despite an attempt to assist the circulation by an intra-aortic ballon, the patient died within a few hours. The postmortem examination confirmed the presence of a massive infarction of the left ventricle, but also of the right ventricle, together with rupture of the posterior papillary muscle of the mitral valve, and ischaemic rupture of one papillary muscle of the tricuspid valve.

Electrocardiography↗
PubMed1977

[Arrhythmias and chronobiology].

The cyclical changes in biological events have seldom been studied by cardiologists. No complete systematic method of study has ever been applied to them. It is, however, certain that the circadian rhythms play a very important role in cardiac patients. This can be seen to be so in the arrhythmias. In a preliminary report, the authors give several examples of this concept; they have obtained their material by using a computerised magnetic tape recording of the electrocardiogram during a 24 hour period.

Adult↗
PubMed1976

Myofibrillar ATPase, DNA and hydroxyproline content of human hypertrophied heart.

70 human hearts were studied less than 36 hours after death. The apex, and in some cases other parts of the myocardium were homogenized, DNA, hydroxyproline content, myofibrillar Ca2+ and Mg2+ ATPase were measured. In normal hearts the DNA and collagen content were 372 +/- 9 mg and 36 +/- 7 mg. Ca2+ and Mg2+ ATPase of the myofibrils prepared from these hearts have shown the same specific activity (35 +/- 5 and 34 +/- 6 nmol/min./mg) as those from fresh biopsies taken during open-chest surgery. The heart weight correlates with the DNA content (r= + 0.58 -p less than 0.01) and with the myofibrillar ATPase (r= - 0.33 - p less than 0.02) but not with the DNA concentration nor with the collagen content or concentration. The main result of this study was the presence of a negative correlation between the DNA content of the heart and the Mg2+ or Ca2+ myofibrillar ATPase (r= - 0.31, p less than 0.05 - r= - 0.45, p less than 0.01). This correlation was analysed with reference to the histological and biochemical studies published by several authors in human or experimental heart hypertrophy and it was suggested that in human heart hypertrophy the decrease of the myofibrillar or myosin ATPase is a direct consequence of the high degree of polyploidy of the muscular cells observed in this condition.

Adenosine Triphosphatases↗
PubMedDate not supplied

Experimental cardiac hypertrophy in rabbits after aortic stenosis or incompetence or both.

Four different models of experimental cardiac hypertrophy were compared : abdominal or thoracic aortic stenosis, aortic incompetence and aortic incompetence associated with a thoracic aortic stenosis. After 3 months the ventricular weight of these 4 models reaches +60% +/- 24; +23 +/- 4; +54% +/- 10 and +83% +/- 14. The maximal increase of left ventricular weight (+94% +/- 15) was obtained with the two-step overloading model. Most of the animals had an increase in the right ventricle and lung weights. The DNA content and the protein myofibrillar protein synthesis were both increased in aortic stenosis and were normal in aortic insufficiency. So far the only way to increase the heart weight experimentally more than 60%, is to combine two lesions.

Animals↗