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H Le Marec

Publications and source records attributed to H Le Marec.

12 recordsLinked to original sources
PubMed1992

[Biological myolysis during combined fenofibrate-pravastatin therapy].

The authors report a case of biological myolysis related to combined fenofibrate-pravastatin therapy in the course of a change in treatment. This case suggests that the risk of myolysis is not specific to the association of some compounds of the two classes but is inherent in possible combinations of drugs from these two families. One must therefore abstain from prescribing these two classes of drugs, since there is no evidence that the combination is preferable to the HMG CoA inhibitor administered alone and the risk of iatrogenic complications is increased. Finally, during the passage from fibrate to HMG CoA reductase a treatment-free interval of about one week should be mandatory.

Angina Pectoris↗
PubMed1992

[Arrhythmogenic effects of sultopride chlorhydrate: clinical and cellular electrophysiological correlation].

This study was designed following the first documented case of torsades de pointes induced by sultopride hydrochloride, a substituted benzamide neuroleptic drug. The patient, a 48 year-old woman with no known cardiovascular disease, had been treated for several years with this drug. She was admitted for severe bronchospasm requiring artificial ventilation. Twenty-one hours after her admission, she developed several episodes of torsades de pointes, which were successfully treated with magnesium sulphate. At that time, the QT interval was 500 ms for a heart rate of 108 b.min-1 (QTc of 668 ms, and theoretical QTc 370 ms). On the fourth day, QTc was 548 ms and theoretical QTc 370 ms. The sultopride was stopped on the fifth day. Two days later, QTc was 397 ms. Six months later, there was no recurrence. Several cases of TdP or sudden death have been reported in patients receiving neuroleptic drugs. The effects of sultopride hydrochloride were therefore tested on isolated ferret Purkinje fibres, using the microelectrode technique. Three concentrations of the drug (D1, D2, D3) were tested, as well as normal Tyrode solution. Maximum diastolic potentials (Vmax) were -88.37 +/- 0.89 mV (control), -89.08 +/- 1.20 mV (D1), -90.00 +/- 1.06 mV (D2), and -90.14 +/- 1.20 mV (D3). Vmax was not affected by sultopride during pacing at 1,000 ms of cycle length. The duration of the action potential increased with the drug concentration. There was no early after-depolarisation (EAD) during control, and 7 out of 9 fibers had EAD and 3 out of 9 triggered activity in D3. The solvent (benzyl alcohol) did not modify the action potential.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1992

MIBG scintigraphy of a patient with pheochromocytoma on labetalol therapy.

A patient with pheochromocytoma was studied by MIBG scintigraphy while on labetalol therapy, which has been reported to interfere with imaging. Serial imaging was performed at 2, 18, 25, and 90 hours to obtain time/activity curves. Blood samples were taken at each imaging study to determine activity counts. Tumor activity per gram of tissue (surgery 116 hours after injection) was compared with blood activity. Tumor and blood activity decreased concurrently, whereas the decrease in peritumoral activity was faster, thus providing transiently improved contrast on 18- and 25-hour images. The diagnostic implications of these results are discussed.

3-Iodobenzylguanidine↗
PubMed1992

[Effects of magnesium on early post-depolarization and trigger activity induced by cesium on Purkinje fibers in ferrets].

The effects of magnesium (Mg) on afterdepolarisations and cesium-induced activity were studied in 15 preparations of ferret Purkinje fibres. When the perfusion medium was enriched with Mg to concentrations of 5 mM, the duration of the action potentials stopped increasing and the diastolic membrane potential was stabilised despite persistent exposure to cesium. A suppressor effect of Mg on the high and low voltage early afterdepolarisations was observed which was significant at 2.2 mM (p less than 0.03) and even more so at 5 mM (p = 3. 10-5) related to a lower probability of early afterdepolarisations. A suppressor effect of Mg on high and low voltage induced activities was also recorded, significant at 5 mM, due to a reduction in the probability of apparition of a first induced action potential (p = 2. 10-4) and a reduction in the number of induced action potentials (p = 8. 10-4). The rapid onset of action (a few minutes) of Mg suggests an extracellular mode of action. The suppressor effect of Mg is probably related to inhibition of an unmasked current by the cesium, a calcium antagonist effect and/or non-specific membrane stabilising effect. The suppressor effect of Mg on early afterdepolarisations and induced activity could, at least partially, explain its in vito antiarrhythmic action on torsades de pointe.

Action Potentials↗
PubMed1991

Triggered activity as a possible mechanism for arrhythmias in ventricular hypertrophy.

To study the cellular mechanisms of arrhythmias occurring in cardiac hypertrophy, we performed standard microelectrode studies on papillary muscles isolated from control (group N) and hypertrophied ferrets right ventricles. Different stages of hypertrophy, induced by pulmonary banding, were studied: 10-22 days (group H1), 4-6 weeks (H2), and 5 1/2-6 months (H3). During the development of hypertrophy, under beta-adrenergic stimulation, triggered activity (TA) induced by delayed afterdepolarizations appeared in 2 of 5 muscles in group H1 and 8 of 8 in group H2. This arrhythmia was absent in N muscles, as well as in H3, despite a pronounced prolongation of the action potentials at 50% (100 +/- 9.3 msec in group H3 vs 67 +/- 5.7 msec in H2; P less than 0.01) and 90% of repolarization (225 +/- 8.7 in H3 vs 185 +/- 7.4 msec in H2; P less than 0.02). The presence of TA was associated with an increase in the intracellular calcium activity (144 +/- 60 nM in H2 vs 47 +/- 9 nM in N; P less than 0.05). TA properties were as follows. Triggering frequency increased as beta-adrenergic stimulation increased, as pacing cycle length (PCL) decreased, and as duration of the prestimulative pause increased. The duration of salvos of TA increased as duration of the prestimulative pauses increased (NS). The coupling interval of the first triggered beat decreased as PCL decreased (P less than 0.001). The minimal cycle length of salvos of TA was not modified by these parameters. It is concluded that delayed afterdepolarizations-induced TA may occur under beta-adrenergic stimulation during the first stages of ventricular hypertrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1991

[Inotropic and vasopressive drugs during anesthesia and critical care. Current data].

Recent therapeutic advances in inotropic drugs and vasipressors uses allow a reappraisal of their indications during the perioperative period. Non-catecholamines vasopressors, ephedrine and phenylephrine, are particularly suitable for treatment of abrupt peroperative arterial hypotensions as observed during induction of general and medullar anesthesias. Cardiac arrest, peroperative anaphylactoid and toxic accidents are treated with epinephrine. In non-cardiac surgery, circulatory insufficiency is usually due to a peripherical origin. Cardiogenic failure occurs in rare cases mainly in vascular surgery. Therefore dopamine remains the first amine to be used in non-cardiac surgery in conjunction with volume expansion. A cardiogenic factor is responsible for most of low-cardiac output syndromes observed after cardiopulmonary bypass for cardiac surgery. However, hypovolemia may be involved and could be undiagnosed. For these reasons, dobutamine is used because of its rapid half-life of elimination and its potent effects. Inodilators (enoximone, amrinone and milrinone) ans nex dopaminergic compound (dopexamine) are powerful vasodilators agents to be introduced with care when association of amines and current vasodilators have failed. Finally, arterial pressure has to be maintained with norepinephrine after dopamine failure. Epinephrine remains last chance.

Anesthesia, General↗
PubMed1989

[Wolff-Parkinson-White syndrome. Value of transesophageal atrial stimulation coupled with exercise test for the study of anterograde conduction in the accessory pathway].

In patients with Wolff-Parkinson-White syndrome the anterograde conduction properties of the accessory pathway determine the ventricular rate in case of atrial fibrillation (AF). Anterograde conduction in the accessory pathway was evaluated in 20 patients (mean age 31 years) by means of transoesophageal atrial pacing with increasing frequency (up to 460 per minute), first at rest, then during exercise on an ergometric bicycle and upon immediate recovery. The exploration was completed by a search for the disappearance of pre-excitation during exercise and after an intravenous injection of ajmaline 1 mg/kg. The shortest cycle (SC) of atrial pacing with 1:1 conduction by the accessory pathway regularly decreased by 80 +/- 26 ms (n = 18), i.e. 27 p. 100 of its value at rest. At immediate recovery SC increased by 40 +/- 53 ms (n = 9). Atrial fibrillation was induced at rest and/or during exercise in 12 patients. The shortest interval (SI) between two pre-excited ventricular complexes was 290 +/- 80 ms (n = 8) at rest and 244 +/- 53 ms (n = 8) during exercise. With a substantial group of values (n = 12) there was good correlation between SC and SI both at rest and during exercise. With a smaller group of values (n = 3) SI was clearly greater than SC, suggesting a concealed conduction in the accessory pathway during atrial fibrillation. Disappearance of pre-excitation during exercise was observed in 4 patients, 3 of whom had a short (less than 250 ms) SC and/or SI.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

[Which pacemaker for which patient?].

Since the early 1980's, in parallel to development of "physiological" cardiac stimulation, modalities and objectives for cardiac stimulation have been modified radically. Among the many methods of stimulation available, in practice the physician may choose from four main types: (1) single-chamber ventricular stimulation; (2) single-chamber atrial stimulation; (3) two-chamber stimulation; (4) variable rate stimulation. Three main elements determine choice of the method of stimulation: the patient's physical condition, his heart condition (nature and type of cardiopathy and hemodynamic profile) and of course, electrophysiological data and cardiac rhythm encountered. The object of this paper is to schematically describe this choice.

Arrhythmias, Cardiac↗
PubMed1986

[Coronary intramural ruptures caused by transluminal angioplasty. Incidence, significance and development controlled by coronary angiography].

The authors report their experience of coronary intimal rupture (CIR) observed at control angiography performed at the end of transluminal angioplasty in a series of 150 cases. This lesion was observed in 34 p. 100 of cases. Two subgroups were established according to the presence (Group I: 51 cases) or absence of CIR (Group II: 99 cases) in order to try and identify any predisposing factor. The following features were compared in each group: age, sex, number of risk factors, duration of the disease, its severity, the site and morphology of the lesions (calcification, length, excentric or concentric) on the artery dilated and the technique used (number of inflations, maximal pressure, guidable catheter). The only significant feature associated with CIR was the morphology of the stenosis. Intimal rupture was statistically more frequent when the stenosis was long, calcific and excentric (p less than 0.05). The excentric character was highly predictive of CIR +/- 0.02) and even of complicated CIR (p less than 0.01). The CIR was complicated in 10 cases (19.6 p. 100) with a higher incidence than in the rest of the population (p less than 0.05). These complications were immediate presenting as attacks of angina leading on to 4 myocardial infarctions (7.8 p. 100) but no deaths. The treatment consisted in an attempt to redilate the artery with effective angioplasty in 3 out of 4 cases. Medical therapy alone was sufficient in 2 cases and 4 patients underwent coronary bypass. There were no complications in cases of initially asymptomatic intimal rupture. The 6 months outcome was controlled by coronary angiography in 131 angioplasties.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1985

Study of a myoglobin test in patients hospitalized for suspected myocardial infarction.

An immunoagglutination latex test was studied in comparison with a plasma myoglobin radioimmunoassay in 103 subjects with suspected myocardial infarction. The test provided an early and reliable indication of raised plasma myoglobin (greater than 85 micrograms/l), a biochemical marker for the early phase (12 h) of myocardial infarction. The diagnostic values (sensitivity and specificity) studied over a 36 h period were the same as those for the plasma myoglobin assay. The sensitivity was similar to that of creatine kinase activity and better than that of the creatine kinase MB/creatine kinase ratio; the lower specificity was due to false-positive results in some subjects with angina. The myoglobin test, which provides rapid results, may be substituted in early diagnosis of myocardial infarction for the plasma myoglobin assay which is unsuitable for emergency analysis.

Aged↗
PubMed1985

Electrophysiologic effects of AHR 10718 on isolated cardiac tissues.

We used microelectrode and blood superfusion techniques to study the electrophysiologic effects of a new antiarrhythmic compound, AHR 10718 (N'-(2-(diethylamino)ethyl)-N-(1-methylethyl)-N-(2-(phenylsulfonyl )ethyl)urea,(Z)-butanedioate) on the electrophysiologic properties of canine Purkinje fibers and papillary muscles. AHR 10718 (greater than or equal to 5 X 10(-6) M) induced a use-dependent decrease in Vmax and significantly decreased Purkinje fiber conduction velocity and action potential duration. In addition, membrane responsiveness was depressed and the effective refractory period shortened. The effects of AHR 10718 were not highly dependent on [K+]0. Vmax of ventricular muscle action potentials also was reduced. However, in contrast to Purkinje fibers, ventricular muscle action potentials were significantly prolonged by AHR 10718 (greater than or equal to 5 X 10(-6) M). AHR 10718 had no effect on slow response action potentials induced by isoproterenol and high [K+]0. AHR 10718 significantly decreased normal automaticity, catecholamine-enhanced automaticity, and abnormal automaticity induced by barium or myocardial infarction. It also suppressed triggered activity and reduced delayed afterdepolarization amplitude in ouabain-treated Purkinje fibers and infarcted myocardium. These studies suggest that AHR 10718 may be effective against arrhythmias resulting from conduction disturbances and certain forms of abnormal impulse initiation.

Action Potentials↗