PubMed Health⌕ Search

Biomedical subjects

J F Leclercq

Publications and source records attributed to J F Leclercq.

At least 73 records · Page 4Linked to original sources
PubMed1986

Comparison of four beta-blockers as assessed by 24-hour ECG recording.

beta-Blockers are used as if they were equivalent. With ECG recordings in 42 patients we investigated the effect on sinus heart rate of four beta-blockers given at three successive daily doses. Heart rate was dose-dependently decreased by all drugs except acebutolol, the effect of which decreased at a higher dosage. The maximal effects of metoprolol, nadolol, and propranolol were similar but the drugs differed in potency (dosage producing 50% of maximal effect, calculated from the dose-effect relationships; nadolol, 0.3 mg/day; metoprolol, 120 mg/day; propranolol, 47 mg/day). Similar relationships were found with drug plasma concentrations (concentration producing 50% of maximal effect: nadolol, 3.5 ng/ml; metoprolol, 21 ng/ml; propranolol, 36 ng/ml) and with supine or upright heart rates and blood pressures. However, the drugs were not equivalent: In addition to its greater potency, nadolol differed from propranolol and metoprolol in the slope of its dose-response curve. We conclude that beta-blockers can be compared by ECG recordings and that nadolol is different from the other beta-blockers without intrinsic sympathomimetic activity.

Acebutolol↗
PubMed1986

[Computer analysis of ambulatory electrocardiograms. Electrophysiological value of the Holter method].

Ambulatory electrocardiography (Holter method) is a technique which is well adapted to the recording of arrhythmias occurring during normal everyday activities. This data is assessed by conventional computer techniques with the object of quantifying the phenomena recorded. However, data processing should not be limited to these as more comprehensive methods of analysis are now available. An attack of arrhythmia is in fact never a chance happening. If one studies the context and the sequence of cardiac cycles leading up to the arrhythmia, the close relationship between arrhythmias and the autonomic nervous system becomes apparent with important therapeutic implications.

Arrhythmias, Cardiac↗
PubMed1986

The clinical use of beta-blockers in the prevention of sudden death.

Numerous studies now suggest that better prevention of arrhythmic sudden death (SD) is provided by beta-blockers than by type I antiarrhythmic drugs. Analysis of 69 cases of SD recorded at ambulatory ECG showed two important facts: (1) in about 20% of the cases, type I antiarrhythmic drugs were responsible for SD, so that the statistical lack of prevention probably reflects a mixed picture of beneficial and deleterious effects; (2) the apparent ineffectiveness of beta-blockers in daily observed arrhythmias does not imply that they cannot protect the patients against the exceptional circumstances which lead to lethal arrhythmias. Arguments suggesting that sympathetic drive should be tempered for a better protection against SD come from various observations: transient ischaemia preceding the terminal event, increasing heart rate preceding lethal or life-threatening arrhythmias, persistent arrhythmias inducibility with isoprenaline or exercise when they had apparently been controlled, the positive correlation between the number of premature beats and the sinus rate at Holter monitoring and the consistent sinus acceleration before a variety of arrhythmias at Holter monitoring. Electrophysiologic phenomena and the autonomic nervous system are often combined to generate arrhythmias. Drugs may apparently be effective though not specific for the causal mechanism, or may be apparently ineffective though providing real protection against potential arrhythmias. Modes of evaluation of the different situations should be more comprehensive to ensure better adapted treatments.

Adrenergic beta-Antagonists↗
PubMed1986

[Double fulguration of the bundles of His and Kent for recurrent tachycardia in Wolff-Parkinson-White syndrome].

A 59 year old patient with a left postero-septal Kent bundle had daily attacks of reciprocating tachycardia resistant to anti-arrhythmic therapy and was referred for catheter ablation. Kent bundle activity was recorded in the proximal part of the coronary sinus. An endocavitary electric shock delivered at this site suppressed conduction through the Kent bundle for several minutes. Catheter ablation of the His bundle (2 X 200 joules) was then attempted suppressing anterograde conduction for 2 days, after which conduction was reestablished and the reciprocating tachycardia recurred. A second session of catheter ablation was carried out and 2 X 200 joules shocks were delivered in the coronary sinus and 4 to the Bundle of His. Complete anterograde and retrograde atrioventricular block was obtained. Two weeks later, the patient recovered anterograde conduction through the accessory pathway. Retrograde conduction through the Kent bundle was decremental, RP' lengthening with increasing heart rate. Conduction was detected in the His bundle but was insufficient to give rise to reciprocating rhythm. After one year's follow-up the patient was asymptomatic without treatment. Catheter ablation of physiological or accessory conduction pathways provides a valuable alternative to surgical treatment of pre-excitation pathways in the WPW syndrome resistant to medical therapy.

Bundle of His↗
PubMed1986

[Mechanisms determining sudden death. A cooperative study of 69 cases recorded using the Holter method].

A cooperative study involving 23 centres enabled review of 69 cases of sudden death occurring less than one hour after onset of symptoms recorded by the Holter method and not related to recent, clinically documented myocardial infarction or to class IV cardiac failure. The 15 cases of asystole (22 p. cent) were observed in elderly patients (73.3 +/- 2.7 years) whose known ischaemic heart disease (12/15) was confirmed in 10 cases as the direct cause by the preceding acute ST changes. In 2 cases, death resulted from AV block presumed to be iatrogenic. The 13 episodes of torsades de point (19 p. cent) occurred mainly in younger women (58.8 +/- 6 years) without apparent cardiac disease (8 cases) and were provoked by a Group IA antiarrhythmic drug (7 cases) or by hypokalemia (3 cases). Apart from 1 case of congenital long QT syndrome, slowing of the sinus rhythm was observed (78.3 +/- 2.6 to 60.2 +/- 2.7 bpm, p less than 0.001) in the 3 hours preceding these episodes, and ventricular bigeminy with a long coupling interval was recorded in the lasts seconds before the torsades. The 41 (59 p. cent) cases of ventricular fibrillation (VF) were observed in men aged 64.9 +/- 2 years with coronary artery disease (39/41). However signs of acute ischaemia were only found in 5 cases. The VF was primary in 8 cases and secondary to ventricular tachycardia (VT in 33 cases). An acceleration of the cardiac rhythm (83.3 +/- 3.4 to 90 +/- 4.1 bpm, p less than 0.01) was recorded in the hour preceding VF and other arrhythmias were common: atrial tachycardia (4 cases), atrial extrasystoles (4 cases), a new type of ventricular extrasystoles (VES). The VF and VT were preceded by a long cycle in 17 cases. The first complex was different from previous VES in 10 cases and identical to the previous VES in 16 cases; in 4 cases this feature could not be identified and in 11 cases there were no premonitory VES. The coupling interval of the initial VES was shorter than that of the most premature preceding VES (368 +/- 13 ms vs 442 +/- 19 ms, p less than 0.001), especially in primary VF (335 +/- 9 ms, N = 8) compared to polymorphic VT (360 +/- 12 ms, N = 11) or monomorphic VT (384 +/- 18 ms N = 22).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1986

[Determining factors of the repetitive bursts in ventricular tachycardia].

24-h ECG recordings were studied in 60 patients suffering from salvos of repetitive ventricular tachycardia (VT), in order to determine the parameters affecting the repetitive response in ventricular arrhythmias. The tracings were analysed with the use of ATREC II system allowing the systematic study of 15 RR intervals and the heart rate in the 3 min preceding each type of event. The mean number of events taken into account per patient and per 24h of recording amounted to 673 +/- 521 for isolated ventricular extrasystoles, to 568 +/- 461 for paired ventricular extrasystoles and 435 +/- 810 for bursts of VT. The whole group was divided into two groups according to the absence (A) or presence (B) of associated cardiopathy. Group A included 30 patients with a mean age of 42 +/- 17 years, group B included 30 patients with a mean age of 42 +/- 17 years, group B included 30 patients with a mean age of 57.4 +/- 12 years. Three major factors responsible for the repetitive activity could be disclosed: The heart rate preceding isolated ventricular extrasystoles was lower than that preceding the salvos of VT (p less than 0.01) the duration of which increased in a linear way with the sinus rate; Duration of the cycle preceding the last sinus beat before the bursts (long duration in 77% in group A and in 57% in group B). In 60% of cases in group A and 40% in group B the coupling interval was all the more long as the response was repetitive.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

[Value of flecainide in supraventricular arrhythmias].

Flecainide acetate (Flecaine) is a new antiarrhythmic which has recently become available; its efficacity in treatment of ventricular rhythm disorders has been amply demonstrated. In this study we have evaluated its efficacity per os in treatment of auricular rhythm disorders refractory to the usual therapies, and its effects on the accessory routes of atrioventricular conduction. The results are very promising and better than those obtained with amiodarone in auricular disorders. They show that flecainide is a drug of importance among therapeutic agents used in treatment of auricular arrhythmia, and its action on Kent's bundle makes it a drug of choice in management of Wolff-Parkinson-White syndrome, especially as it seems equally efficacious in its action on the accessory routes with a short refractory period. Most of our patients did not present organic cardiopathy and the side-effects were generally benign. A non-negligible number of cases of paroxysmal hypertension were noted, in disagreement with literature data, and this point needs to be clarified by further study.

Adolescent↗
PubMed1985

[New antiarrhythmia agents: propafenone and flecainide].

The electrophysiological and antiarrhythmic properties of two new drugs, propafenone and flecainide, are distinctly different from those of known products of the same therapeutic category. Compared with other class I (membrane-stabilising) antiarrhythmic agents, propafenone exerts a beta-adrenergic inhibitory effect which may be clinically useful, and flecainide has a stronger depressant effect on intraventricular conduction. There is no prolongation of Q-T nor any risk of wave burst arrhythmia with either of these drugs. Their antiarrhythmic activities are superior to those of class I compounds currently available and they can be combined with amiodarone, which considerably potentializes these activities. Their extracardiac side-effects are rarely limitating. However, their intracardiac side-effects on the sinus node an on distal conduction may result in disorders of conduction or severe drug induced arrhythmia in patients with fragile conduction system or cardiac failure.

Anti-Arrhythmia Agents↗
PubMed1985

Suppression of arrhythmias within hours after a single oral dose of amiodarone and relation to plasma and myocardial concentrations.

In 65 patients a single oral dose of amiodarone (30 mg/kg) produced an antiarrhythmic effect on supraventricular or ventricular arrhythmias within 3 to 8 hours and lasted for 17 to 19 hours. On the second day a 15-mg/kg dose reproduced this effect within 3 to 9 hours. Plasma concentration of amiodarone increased to a maximum (2.2 +/- 1.7 mg/liter) mean +/- standard deviation) at 6 +/- 3.5 hours and plasma levels of N-desethylamiodarone (NDA) rose to 0.2 +/- 0.08 mg/liter at 12 +/- 6.4 hours. Sixty-one other patients were given a single 30-mg/kg dose 7 hours to 4 days before open heart surgery. Biopsies of the right atrial and left ventricular walls were taken during surgery. Myocardial concentration of amiodarone was maximal in the atrium after 7 hours (13 +/- 8 mg/kg) and in the ventricle after 24 hours (17 +/- 11 mg/kg). NDA myocardial concentration increased progressively until 24 hours and then remained stable over 4 days (1.5 mg/kg). The amiodarone myocardial to plasma concentration ratio was similar in the atrium and in the ventricle and averaged 22 and 10 for amiodarone and NDA, respectively. A significant relation existed between amiodarone concentration and the effect on ventricular premature complexes (r = 0.74, p less than 0.001) and between amiodarone plasma concentration and the effect on the atrioventricular conduction (r = 0.58, p less than 0.001). The plasma concentration of amiodarone corresponding to a 60% decrease in arrhythmias averaged 1.5 to 2 mg/liter.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1985

[Pathogenesis of tachycardia in hyperthyroidism. Value of Holter monitoring and the use of a beta-blocker].

The mechanisms of tachycardia in hyperthyroidism were investigated by means of Holter recordings of heart rate in 45 patients, 33 of whom had sinus rhythm and were left untreated. In the remaining 12 patients, recordings were taken after 3 days of treatment with either propranolol (120 mg/day; 6 patients) or pindolol (15 mg/day; 6 patients). Propranolol is a beta-blocker devoid of intrinsic sympathetic activity whereas pindolol possesses such activity. Changes in heart rate under the influence of each of these drugs were compared with those observed in 96 controls similarly treated. The difference in baseline heart rare between day and night was significantly higher (p less than 0.01) in patients with hyperthyroidism (17 +/- 1 QRS/min) than in controls (13 +/- 1 QRS/min). Day and night heart rates were increased by pindolol, the increase in night heart rate being significantly greater (p less than 0.05) in patients with hyperthyroidism (23.4 +/- 4.9%) than in controls (11.6 +/- 2.6%). These results suggest that sinus tachycardia in hyperthyroidism is related to an increase in the number of myocardial beta-adrenoceptors. They also indicate that thyrotoxicosis should not be treated with beta-blockers possessing intrinsic sympathetic activity.

Adolescent↗
PubMed1985

Possible mechanisms of the arrhythmias in the long QT syndrome.

Torsades de pointes (TP) are observed in the setting of four different clinical syndromes. Two are easily recognized by prolongation of the QT interval: acquired and congenital long QT syndromes (LQTS). Two have no patent long QT, but they do have many characteristics in common with the LQTS: catecholamine-dependent ventricular tachycardias, and short-coupled TP. The mechanism of TP is undetermined. Re-entry phenomena as well as early after depolarizations, occurring in a single or several arrhythmogenic areas may equally explain the curious pattern and behaviour of TP, and the lack of an experimental model makes difficult the progress of our knowledge. A fundamental myocardial disorder might be common to the different clinical syndromes. The existence of a substrate for the arrhythmia was reflected in one of our patients by the large discrepancy between the endocardial and epicardial refractory period duration. A common substrate, with different inputs and outputs, would explain consistently (a) why the autonomic nervous system is always involved in triggering TP, but in variable and even opposite ways according to the syndrome in cause, and (b) why the TP response to drugs is also variable and often paradoxical.

Adolescent↗
PubMed1985

[Anti-arrhythmic effect of amiodarone in the 24 hours following a single oral loading dose. Clinical and pharmacological study].

This study demonstrated the rapid antiarrhythmic effects of oral amiodarone (Am). A single 30 mg/kg dose was given to 67 patients, 18 with supraventricular arrhythmias (atrial extrasystoles: 11 cases, reciprocating tachycardia: 4 cases, intraatrial reentrant tachycardia: 2 cases, paroxysmal atrial fibrillation, AF: 1 case). Eighteen patients had permanent AF. Thirty-one patients had ventricular arrhythmias (ventricular extrasystoles, VES, isolated or in salvos: 22 cases, and ventricular tachycardia, VT: 19 cases). The effect on atrial extrasystoles was significant 4 to 13 hours after AM and maximal (-98% +/- 3.6%) at 7.7 +/- 1 hours. They recurred in 3 cases at the 18th hour. No significant effects were observed on the other supraventricular tachycardias. The effect on the atrioventricular node (AVN) assessed by the ventricular response to permanent AF, was significant after the 3rd hour and maximal ( = 38 +/- 6 bpm) at the 7th hour. The reduction in the frequency of VES was significant from the 5th to the 19th hour of treatment. Control of VT was obtained in 5 cases between the 3rd and 8th hours. The treatment was well tolerated as no side effects were reported. The plasma concentration (PC) of amiodarone (54 patients) and of N-desethylamiodarone (NDA) (36 patients) were measured; the maximal values were 2.53 +/- 1.5 mg/l for Am and 0.22 +/- 0.1 mg/l for NDA. A 60% decrease in the number of VES was observed with PC of Am of 1.90 +/- 0.3 mg/l and a 20% reduction in the ventricular response to AF at PC of Am of 1.50 +/- 0.33 mg/l.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1985

[Block of the atrioventricular trunk: diagnosis of the site by Holter monitoring].

Twelve patients with intrahisian AV block, confirmed later by electrophysiological investigations had Holter recordings showing the block (paroxysmal in 11 cases, permanent in 1 case). The diagnosis of the site of the block was made before endocavitary investigation in all cases on the following criteria: narrow QRS complexes in 10 out of 11 paroxysmal blocks (1 with phase III LBBB) with a sudden transition from 1/1 to 2/1 conduction. Only 3 patients had rare sequences of lower degree, Mobitz II block. Only 3 patients had 2 or more consecutive blocked P waves. The role of sinus tachycardia (block in phase III) was demonstrated in 10 out of 11 cases. The block was found on the first 24 hour Holter recording in all but 1 patient. This contrasts with paroxysmal trifascicular block: out of 46 patients recruited during the same period, only 4 had Holter recordings showing the block and this was not reproducible. The 12th patient had permanent AV block with wide QRS complexes and narrow sinus captures in the supernormal period in the morning. The sudden transition from 1/1 to 2/1 conduction in phase III is characteristic of intrahisian block and distinguishes it from intranodal AV block. All patients were improved by VDD mode pacing.

Aged↗
PubMed1984

European experience with the antiarrhythmic efficacy of propafenone for supraventricular and ventricular arrhythmias.

Seventy-one patients (mean age 53 years) were treated with oral propafenone, 900 mg/day, for a mean of 6.6 months. A large spectrum of arrhythmias was encountered, and particular attention was paid to their relation with the autonomic nervous system. Drug efficacy was graded from 1 (no effect) to 5 (complete control) according to the clinical result and Holter recording. This method permitted comparisons to be made between propafenone and 3 other antiarrhythmic agents: quinidine, beta-blockers and amiodarone. Among the 32 patients with supraventricular arrhythmias, 9 cases of vagally dependent atrial flutter and fibrillation were less sensitive to propafenone (mean effect 1.4) than to quinidine (mean effect 2.0) or amiodarone (mean effect 2.3). However, 8 cases of adrenergically dependent atrial tachycardia and fibrillation were more sensitive to propafenone (mean effect 4.1) than to beta blockers (3.0) or amiodarone (mean effect 3.5). In 12 cases of miscellaneous atrial arrhythmias the response to propafenone was intermediate. However, 3 patients with resistant junctional tachycardia were improved with propafenone. Among 42 ventricular arrhythmias, 5 patients with extrasystole who were responsive to quinidine (mean effect 3.8) were also improved with propafenone (mean effect 4.6). Propafenone (mean effect 4.1) was much more effective than quinidine (mean effect 2.4) in treating 8 cases of idiopathic benign ventricular tachycardia and even more successful in treating 13 cases of more severe arrhythmias in diseased hearts (propafenone's mean effect 4.1, quinidine's mean effect 1.9 and amiodarone's mean effect 1.9). Propafenone was less effective (mean effect 3.3) than amiodarone (mean effect 4.0) in 4 cases of severe, adrenergically dependent idiopathic ventricular tachycardia (VT).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

The QRS morphology in post-myocardial infarction ventricular tachycardia. A study of 100 tracings compared with 70 cases of idiopathic ventricular tachycardia.

A hundred tracings of ventricular tachycardia (VT) belonging to 85 patients with myocardial infarction (MI) were compared with 70 cases of incessant, benign, idiopathic VT. The two groups of tracings differed in terms of QRS axis, most often normal in idiopathic VT (75%) and outside normality in MIVT (74%). The sum of QRS amplitude in unipolar limb leads was greater in idiopathic VT (4.3 +/- 1.3 mv, mean +/- S.D.) than in MIVT (2.6 +/- 0.8 mv, P less than 0.001). The QRS width was also different: 135 +/- 11 ms in idiopathic VT vs. 171 +/- 32 ms in MIVT (P less than 0.001). The QRS morphology in MIVT was characterized by the presence of a QR pattern in leads other than VR, or a QS pattern in V5-V6. These two aspects were constantly absent in idiopathic VT, and they were present in 89% of MIVT. In only 38 MIVT tracings were the ECG signs of MI observed in the same leads during sinus rhythm and during VT. In 51 MIVT tracings the location of the MI indicated by the VT tracing differed from that displayed in sinus rhythm. Rather than indicating an extension of the infarcted area not apparent in the tracings in sinus rhythm, such a discrepancy suggests that the QRS pattern during VT strongly depends on the point of origin of the VT. Conversely, this explains why the morphology of the QRS is an unreliable means for localizing the VT origin if the location of the MI is not taken into account. We conclude that both factors should be taken into consideration, and this might theoretically permit a better though complex approach to the VT origin in coronary heart disease using surface tracings.

Adult↗
PubMed1984

The potential role of the implantable defibrillator in malignant ventricular arrhythmias.

A malignant arrhythmia is one which threatens life and is difficult to predict, prevent or treat. Any arrhythmia which falls into this category is an indication for the implantable defibrillator. The simplicity of this statement is of course deceiving. Transthoracic defibrillation, which for 20 years has been the therapeutic standard, has provided us with the greatest insight and understanding of cardiac arrhythmias. In the long run, the same information will be acquired with the implanted defibrillator. However, technical, medical and economic factors are more complex and will not be resolved in the near future.

Arrhythmias, Cardiac↗
PubMed1984

[Value of long-term electrocardiography in patients with cerebral ischemic accidents].

Continuous 24 hour electrocardiography (Holter monitoring) was performed in 226 patients aged 20 to 85 years (mean 61 years) presenting with focal signs of a cerebrovascular accident (CVA). The technique was the same in all patients; the study was limited to paroxysmal atrial arrhythmias. Eighty four of the 226 patients examined had atrial arrhythmias which were already known in 39 patients before Holter monitoring. In the other 187 cases, the following results were obtained: 1) 9 patients (4,8%) had paroxysmal atrial fibrillation (AF), 2) 6 patients (3,2%) had paroxysmal atrial tachycardia (PAT), 3) 11 patients (5,9%) had runs of atrial extrasystoles, 4) 19 patients (10%) had isolated atrial extrasystoles (IAE). When patients with underlying cardiac disease constituting a diagnostic indicator for arrhythmia were excluded, the following incidences were obtained: AF = 3,7%, PAT = 2,7% and runs of atrial extrasystoles = 4,3%. The majority of these arrhythmias occurred in elderly patients in whom atrial arrhythmias are known to occur and may be asymptomatic. There were practical consequences of these results, i.e. antiarrhythmic and anticoagulant therapy in 12 patients (6,4%) alone. As Holter monitoring is also associated with a number of false negative results with respect to paroxysmal atrial tachycardia, we do not believe that this investigation should be offered routinely to patients with CVA in the absence of other clinical or electrocardiographic indications.

Adult↗