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Biomedical subjects

P Puech

Publications and source records attributed to P Puech.

At least 55 records · Page 3Linked to original sources
PubMed1984

The QT interval: a predictor of the plasma and myocardial concentrations of amiodarone.

A study was performed to assess whether plasma and myocardial concentrations of amiodarone correlated with changes on the surface electrocardiogram. Nine patients--seven with angina and two with paroxysmal ventricular tachycardia--were treated with oral amiodarone (200-400 mg daily) for at least nine months before undergoing cardiac surgery. QT intervals were measured from lead II of the surface electrocardiograms recorded before amiodarone treatment and immediately before surgery. Patients with prominent U waves after taking amiodarone were excluded from the study. Plasma and myocardial samples were collected at the beginning of the surgical procedure for estimating plasma and myocardial concentrations using the high performance liquid chromatographic technique. Amiodarone caused a significant lengthening of the QTc interval. There was a good correlation between plasma and myocardial concentrations, and both correlated well with the percentage increase in the QTc interval. Although there was a strong correlation between the dosage given (mg/kg/day) and both plasma and myocardial concentrations, the correlation with the percentage increase in the QTc interval was weaker but still highly significant. Despite previous reports to the contrary, the findings indicate that the plasma concentration of amiodarone does correlate well with the myocardial concentration. The degree of lengthening of the QTc interval may be used clinically to estimate the myocardial concentration of amiodarone.

Adult↗
PubMed1984

[Treatment by endocavitary fulguration of recurrent ventricular tachycardia caused by right ventricular dysplasia].

A 27 year old man had recurrent ventricular tachycardia since the age of 16. Different antiarrhythmic drugs were used successively without success (mexiletine, amiodarone, acebutolol, propafenone, sotalol). The diagnosis of VT due to arrhythmogenic right ventricular dysplasia was suggested by the morphology of the tachycardia (left-sided delay), surface ECG appearances (right bundle branch block and potential after the QRS in right precordial leads) and the presence of delayed potentials on right ventricular endocavitary recordings. However, there were no obvious RV changes on echo or angiographic examination. The arrhythmogenic zone was localised in the postero-basal zone of the RV using three electrophysiological criteria: the recording of delayed systolic potential in sinus rhythm which overlapped into diastole during tachycardia, mapping of ventricular depolarisation during VT and results of RV "pacemapping" reproducing the appearances of the spontaneous tachycardia. VT was reproducible on stress testing (non-sustained VT at the beginning of the recovery phase) and on endocavitary stimulation. One 250 joule electric discharge between the endocavitary electrodes and a large dorsal surface electrode prevented any further attacks without antiarrhythmic therapy (follow-up: one year). Control electrophysiological investigation after 4 months showed another potentially arrhythmogenic zone which is quiescent at present.

Adult↗
PubMed1984

Cardiac electrophysiological effects of cibenzoline by acute and chronic administration in the anesthetized dog.

The electrophysiological effects of cibenzoline on the myocardium of the anesthetized dog were studied by the endocavitary catheter method. Plasma cibenzoline levels were measured throughout. The cibenzoline effects on the sinus rate were negligible. The corrected sinus recovery time was significantly prolonged only following chronic oral administration. Atrial refractory periods were significantly increased only at the fifth minute following acute intravenous administration and after chronic oral treatment. The intranodal conduction time (AH) and the refractory periods in atrio-ventricular node were slightly modified or not at all. On the other hand, intraventricular and His-Purkinje (HV) conduction times, ventricular refractory periods and QRS duration were strongly increased following acute or chronic administration. This would imply a principal effect on the rapid kinetics sodium entry current. Nevertheless, the very marked effect upon this current could, under the experimental conditions adopted, have masked a lesser action upon other membrane permeabilities, involved in other myocardial structures.

Administration, Oral↗
PubMed1983

Determination of cardiac and plasma drug levels during long-term amiodarone therapy.

A study of plasma and cardiac concentrations of amiodarone during the course of long-term oral therapy was made possible by the improvement of analytical high performance liquid chromatography of plasma and tissue extracts. The plasma level was found to increase linearly with the daily dose of the drug, above a threshold value of c. 1 . 9 mg kg-1 day-1. Similarly, the cardiac content increased linearly with the daily dose, with no threshold, showing that the drug is taken up and accumulated in the cardiac tissue, with no obvious difference between atrial and ventricular samples (P greater than 0 . 05). Both plasma and heart showed no saturation at high drug intake, a justification for increasing the oral intake in severe cases. The linear relationship between tissue and blood concentrations allows a prediction of the cardiac level from a simple and routine blood analysis.

Administration, Oral↗
PubMed1983

[Study of flecainide in the treatment of ventricular arrhythmia].

The effect of flécaïnide (new class I antiarrhythmic) on ventricular rhythm troubles was studied in 24 patients using Holter's method. The following results were obtained. For ventricular tachycardia, two cases of suppression, three cases of distinct reduction in the number and duration of attack and one failure were recorded. For single ventricular extrasystoles, doublets and triplets, nine very good results (80 to 100 per cent reduction of arrhythmia) and four 50 to 80 per cent reductions in ventricular prematurity were obtained. Results were uncertain in two patients as the disappearance of extra-systoles was not followed by relapse after termination of treatment. There were three failures. A twenty-fifth patient was treated with flécaïnide IV followed by oral administration with uncertain results. Undesirable effects are infrequent and are often characterized by sinusal bradycardia. Blurred vision and paraesthesia were encountered. The principal biological parameters remained unchanged.

Adolescent↗
PubMed1983

[Secondary angina pectoris. Generalities].

Secondary angina pectoris (AP) resulting from an increase in myocardial oxygen demands not satisfied by increased coronary flow because of severe and usually multiple atherosclerotic lesions, contrasts with primary AP due to decreased coronary flow usually due to coronary spasm. Secondary AP corresponds clinically to Heberden's common AP induced by conditions which increase the metabolic demands of the myocardium: tachycardia, increased parietal tension and myocardial contractility, prolongation of the ejection period. In practice, secondary AP is preceded by an elevation in the rate-pressure product. Factors which give rise to tachycardia, increased after and preload, increased inotropism and ventricular ejection may cause secondary AP at a critical level of fixed reduction of the coronary vascular bed. Mixed AP is due to the association of fixed anatomical lesions and coronary spasm in variable proportions. The physiopathological principles should be born in mind when taking therapeutic decisions.

Angina Pectoris↗
PubMed1983

Clinical electrophysiology of atrioventricular block.

The diagnosis of various forms of atrioventricular conduction disorder is considered in the light of intracardiac recording techniques. Criteria for the topographic diagnosis of AV block based on intracardiac recordings are described in this article.

Atrial Fibrillation↗
PubMed1983

Electrophysiological properties of butoprozine studied by multiple intracardiac recordings on the anaesthetized dog.

Electrophysiological effects of butoprozine (L 9394 Labaz) were investigated on the anaesthetized dog by programmed electrical stimulation of the heart and simultaneous recording of the His bundle electrogram and monophasic action potentials from the auricular and ventricular endocardial wall. Butoprozine injected intravenously depressed sino-atrial node function, lengthened A-V nodal conduction time and the A-V nodal refractory period, and prolonged the atrial refractory period. Thus butoprozine acted preferentially on parts of the myocardial tissue where the slow inward current seems to be particularly involved. In this respect, butoprozine was more active than amiodarone, but in contrast to this drug, butoprozine did neither prolong the ventricular monophasic action potential duration nor the ventricular refractory period. In the anaesthetized dog both drugs have practically analogous actions except at the ventricular level, which suggests that their effect on ionic currents at this level may be different.

Amiodarone↗
PubMed1979

[Arrhythmia].

Explore the source record for details and available documents.

Aged↗
PubMed1979

[Automatic activity of the pre-excitation pathways].

The possibility of preexcitation pathways exhibiting automatic activity was demonstrated in 3 cases: in two cases electrophysiological studies supported this diagnosis which was confirmed in the third case by histological examination of the preexcitation pathway. During sinus node dysfunction, spontaneous or induced (by rapid right atrial pacing or by a reciprocating tachycardia), the substitute rhythm arose from the Kent Bundle either transiently or for a longer period: rhythms arising from the Kent Bundle can only be diagnosed after eliminating the possibility of an atrioventricular junctional rhythm conducted to the ventricles by Mahaïm fibres.

Adult↗
PubMed1979

[1st degree and 2nd degree blocks (Wenckebach type) during right ventricular stimulation in the course of Prinzmetal's angina].

Right axial deviation and delay between stimulation and ventricular response was observed during pacing of the apex of the right ventricle in Prinzmetal angina. The degree of deformation of the ventricular complex and the length of this delay appear to be related to the severity of the anginan, the length of the preceding diastolic period and the amplitude of stimulation. This observation demonstrates the presence of conduction defects at the heart of ischaemic myocardium and may explain the failure of prophylactic pacing in Prinzmetal angina complicated by paroxysmal atrioventricular block.

Aged↗
PubMed1979

[Improvement and normalisation of the QRS complex by stimulation of the bundle of His in complete left branch block].

The asynchronism of ventricular activation resulting from a major degree of left bundle branch block (QRS greater than or equal to 0.12 s) may be suppressed by stimulation of the distal portion of the His Bundle, whether the block be intermittent (3 cases) or permanent (17 cases). The selective stimulation of the His Bundle normalises ventricular depolarisation whilst non-selective stimulation narrows the QRS complex by the fusion of the activation wave fronts from the His Bundle and the interventricular septum. The reestablishment of synchronous ventricular conduction by His Bundle stimulation is generally interpreted as a sign of longitudinal dissociation in the proximal portion of the His Bundle. This results does not, however, exclude the possibility of a very localised lesion at the origin of the left bundle, responsible for a conduction delay, and suppressed by stimulation carried out close to the zone of block (summation effect, electrotonic influence).

Adult↗
PubMed1979

[Spontaneous blocks by intra-atrial conduction disorders of reciprocating atrioventricular rates using a Kent's bundle].

Paroxysmal tachycardia in Type A Wolff-Parkinson-White syndrome was due to a reciprocating rhythm involving a left lateral Kent Bundle in the retrograde direction. Spontaneous interruption of the reentry resulted not from block in the normal or accessory atrioventricular pathways but from an intraatrial conduction defect: delay in conduction between the left and right atria on intraatrial reentry terminated the tachycardia.

Adult↗