[Improvement and normalisation of the QRS complex by stimulation of the bundle of His in complete left branch block]. / Affinement et normalisation de QRS par stimulation de faisceau de His dans les blocs complets de branche gauche.

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).

[Value of continous 12-hour electrocardiography during the rehabilitation period in patients convalescing from myocardial infarction. Apropos of 40 cases]. / Intérêt de l'enregistrement électrocardiographique continu sur 12 heures de sujets convalescents d'infarctus du myocarde en période de réadaptation. A propos de 40 sujets.

The results of continuous 12-hour electrocardiography in 40 convalescent patients after myocardial infarction undergoing a programme of readaptation on average 4 weeks after the initial infarction are reported. The frequency and alarming nature of the VES observed in 75% patients who had already undergone selection for the coronary readaptation programme, 30% of whom were receiving antiarrhythmic therapy, is emphasized. The observation of a progressive increase in the number of VES during the day prompts the following suggestions: the possibility of limited continuous ECG monitoring at the end of the day, the need to adapt the dosage of antiarrhythmic drugs during this most critical period. The comparison of the results of continuous ECG with those of repeated exercise ECG seems very positive, but some reservations are made and it would seem logical to associate these two complementary methods of investigation.

[Value of potassium canrenoate in the prevention of arrhythmia during the acute phase of myocardial infarction]. / Intérêt du canrénoate de potassium dans la prévention des troubles du rythme à la phase aiguë de l'infarctus du myocarde.

This study was based on a series of 486 patients with acute myocardial infarction. All were treated with heparin and nitrite derivatives. 320 patients received 600 mg/24 h Potassium Canrenoate for 5 days (long duration); 90 patients received 1000 mg of Potassium for the first 36 hours only. 76 patients did not receive the drug and served as controls. The biochemical changes due to Potassium Canrenoate are discussed with special emphasis on the serum and intraerythrocytic potassium levels. The antiarrhythmic action of the potassium was assessed directly (the number of ventricular extra systoles decreased significantly) and indirectly (the amount of antiarrhythmic therapy required in association was three times less in patients treated by Potassium Canrenoate). The mortality rate changed from 17 to 12%. The beneficial effect of Potassium Canrenoate is attributed to the maintenance or the restoration normal potassium levels of ischaemic myocardial tissue.

[Electrophysiological effects of the combined administration of digoxin and propranolol in man]. / Effets électrophysiologiques chez l'homme de l'association digoxine-propranolol.

The electrophysiological effects of the combined administration of digoxin and propranolol were studied in 40 patients, compared with the effects of digoxin alone and considered in relation to anomalies of the conduction pathways. The cycle of the sinus node was only lengthened by digoxin in patients who had an anomaly of sinus node function. In contrast the addition of propranolol always increased it (from 1 109 +/- 53 ms to 1 232 +/- 58 ms). Sinus node recovery time was only increased by combined administration (from 1 331 +/- 101 ms to 1 450 +/- 68 ms). Changes in sino-atrial conduction intervals were not very marked. The AH interval was increased by digoxin (from 97 +/- 4 ms to 109 +/- 6 ms), with propranolol exerting a synergistic effect (119 +/- 6 ms). When there was pre-existing supra-His block only combined administration increased the conduction defect. The HV interval and QRS duration were not altered. The effective atrial refractory period was increased by combined administration (from 264 +/- 10 ms to 304 +/- 14 ms) except in subjects who had supra-His block. The effective refractory period of the AV node (385 +/- 26 ms) was increased by digoxin (450 +/- 37 ms). This effect was potentiated by propranolol (478 +/- 34 ms) except in those subjects who had supra-His block. In three cases in which there were two conduction pathways at A V node level the refractory periods of the rapid and slow pathways were increased by digoxin, with a synergistic effect from propranolol. The ventriculo-atrial conduction time changed from 151 +/- 24 ms to 172 +/- 22 ms following digoxin, then to 193 +/- 34 ms after the addition of propranolol.

[Association of progressive external ophthalmoplegia and myocardiopathy with complete atrioventricular block. Apropos of a new case]. / Association d'une ophtalmoplégie externe progressive et d'une myocardiopathie avec bloc auriculo-ventriculaire complet. A propos d'un nouveau cas

The authors report the case of a 31 year old man with an occulomotor palsy, who was admitted to hospital with complete atrio-ventricular block and syncopal attacks. The possible pathogenic significance of this association has given rise to differing hypotheses. A review of the literature shows that the occulomotor palsy has been interpreted either as an ophtalmoplegia (of neurogenic origin) because of the associated neurological findings and the histological changes in the occulomotor nuclei, or as an occular myopathy because of the associated muscular disorders and the changes on electromyography and on histology. The relationships between the occulomotor palsy and the cardiac condition are also discussed.

[Dromotropic effects of drug combinations. Initial results bearing on a combination of deslanoside and ajmaline]. / Effets dromotropes des associations médicamenteuses. Premiers résultats portant sur l'association deslanoside - ajmaline.

The electrophysiological effects of the cardiotropic drugs have been studied in man by the agency of endocavitary electrocardiography. The effects of drug combinations, which are often prescribed therapeutically, have been studied less often. The authors report the results of a preliminary study of the combination of deslanoside with ajmaline in 26 patients; its effects were compared with those using each drug separately. This combination seems to have true dromotropic effects; although deslanoside alone, in the doses used, does not modify conduction below the bundle of His, it can still act synergistically with ajmaline at this level. A detailed study of the pharmacological effects as a function of the original status of conduction shows that at the level above the bundle His, the dromotropic action is quantitively less on healthy conducting tissue than on abnormal tissue. The effects of ajmaline on the conduction times below the bundle seem to be similar whether or not there is any conduction defect under basal conditions. The difficulties in obtaining and interpreting such measurements in man are discussed in the hope of arriving at a general protocol for studying drug combinations.

[The heart and lithium. Apropos of a case of lithium poisoning with intracavitary electrocardiographic exploration]. / Coeur et lithium. A propos d'une observation d'intoxication par le lithium avec exploration électrocardiographique endocavitaire.

Among the secondary effects of the salts of Li+, which are widely used in psychiatric treatment, cardiac toxicity appears to be rare. The authors report the case history of a female of 24 years of age, with no previous cardiac history, who presented with Li+ intoxication and a supra-His atrio-ventricular block, followed by episodes of sinus arrest (or of sino-atrial block), accompanied by either a junctional rhythm or by periods of prolonged asystole. The results of the endocavitary electrocardiographic investigation are described. These cardiac effects are compared with the general findings reported in the literature; ECG modifications of the T wave are more common, but Li+ may cause other changes: sinus, atrial or ventricular arrhythmiás, disorders of AV conduction, and cardiomyopathies. The main modes of action which have been suggested are of interference with the other cations (K+, Na+, Ca++) in exchanges across membranes, and an effect on membrane adenyl-cyclase stimulated by catechol-amines.

[Diagnosis of posterior infarction. Value of vectorcardiography. Apropos of 108 cases, 31 of which had exclusively posterior necrosis]. / Le diagnostic des infarctus postérieurs. Intérêt du vectocardiogramme. A propos de 108 observations dont 31 cas de nécroses exclusivement postérieures.

An analysis of the vectorcardiogram results (VCG) in 77 cases with a posterior extension of an infarct and 31 cases with an exclusively posterior infarction (EPI) has allowed us to distinguish some diagnostic criteria relative to the extension, or localisation, of an infarct in the posterior segment. The maximum anterior vector (MAV) appears late (36.5 ms +/- 5), and the amplitude of its projection onto Z is increased; the maximum vector (V max) appears early (41.5 ms +/- 4.5), and its orientation is anterior (+ 24 degrees +/- 11); the interval separating MAV from V max is reduced to 5 ms; the transition from before backwards is late (50 ms +/- 6); the ratio of anterior surface to posterior surface is increased (1.45); there is a terminal delay, most frequently occuring in the right posterior quadrant in 78 percent of cases; and finally, the T loop approaches the Z axis. Repeat electrocardiograms in patients with EPI show the most frequent changes to be represented (in 25 cases out of 31) by the following formula: AQRS " 0 degrees, R/S greater than or equal to 1 in V2, RV2 greater than RV6. The diagnosis of an exclusively posterior infarction can therefore be made with a high degree of certainty when these electrocardiographic abnormalities are associated with the clinical picture of coronary insufficiency.

[Carcinoid heart disease secondary to a tumor of the small intestine. Apropos of a case with associated tricuspid and pulmonary insufficiency]. / Cardiopathie carcinoïde secondaire à une tumeur du grêle. A propos d'un cas associant insuffisance tricuspidienne et insuffisance pulmonaire.

The authors report a case of carcinoid heart disease secondary to a tumour of the small bowel with liver metastases. There were severe lesions of the endocardium on the right side of the heart, with gross pulmonary and tricuspid incompetence. The left side of the heart did not escape but the fibrous plaques were limited to the papillary muscle of the mitral valve, and had no effect upon the haemodynamics. The pathogenesis of the strange cardiac lesion may be partly explained in terms of the toxicity to the endothelium of bradykinin. In spite of the serious nature of the valvular damage is it right to consider surgical correction, bearing in mind the fact that the prognosis of carcinoid syndrome is still very poor despite treatment?

[The supernormal phase of cardiac conduction. An experimental study in the dog]. / La phase supernormale de conduction cardiaque. Etude expérimentale chez le chien.

The existence of a cardiac phase of supernormal excitability is not fully proved at the cellular level. As far as the whole heart is concerned, the phenomenon of supernormal conduction is still under discussion. Intracardiac conduction has been studied both in the right atrium (13 dogs) and in the right ventricle (14 dogs) by programmed stimulation (extrastimulus technique), while monophasic action potential (MAP) was recorded. The phenomenon of supernormal conduction was noted in 67.7% of cases, starting at 59.0% and ending at 78.0% of the basic cycle, hence occuring shortly after phase 3 of the MAP. In the ventricle, a phase of supernormal conduction was present in 52.4% of cases, starting at 66.1% and ending at 77.9% of the basic cycle. After ajmaline, the supernormal conduction was moved towards the end of the cycle. The mechanism of supernormal conduction, and its implications in the study of arrhythmias are discussed.

The dependence of T wave alternans on diastolic resting period duration.

The dependence of T-wave alternans on diastolic resting period duration as well as on regional differences in monophasic action potential duration was studied in the in situ dog heart. T-wave alternans was elicited when diastolic resting period shortened to values less than 41 +/- 6% of the cardiac cycle. This could be attained either by increasing the driving rate, or lengthening action potential duration by inducing hypocalcemia. During T-wave alternans, monophasic action potentials recorded from anterior and posterior left ventricular surface showed an alternation in duration; the degree in alternation in both regions differed and related to T-wave polarity.