[Clinical value of the determination of serum digoxin levels (author's transl)]. / Intérêt clinique du dosage sanguin de la digoxine.

The authors refer to the technique of the serum digoxin enzyme immunoassay, and they report the results of 297 dosages concerning 111 hospitalized patients. The normal plasmatic rates are of 1,4 +/- 0,6 microgram/l in patients who present no sign of digitalic overdosage. The rates are of 5,2 +/- 1,6 microgram/l in cases of intoxication. The difference between these rates is greatly significant (p less than 0.001). The limit between therapeutic and toxic rates is situated around 3 microgram/l with an overlapping from 2 to 3 microgram/l. Authors then examine the individual factors that intervene in digoxin metabolism and especially study the influence of age, myocardic factors and renal insufficiency. On the basis of these results and review of the literature, they emphasize the interest of serum digoxin determination in the diagnosis of digitalis toxicity, as well as in the management of high risk patients, and of cardiopathies difficult to stabilize.

Effects of an interpolated premature ventricular contraction on the AV conduction of the subsequent premature atrial depolarization. An apparent facilitation.

Nodal conduction is usually studied by tracing the H1 H2 on function of A1 A2 curves. If one interpolates a PVC before A1, there is a decrease in H1 H2. This might be explained by an A1 H1 interval lengthening (delta A1 H1). This study was done on 14 consecutive patients in whom a PVC can be interpolated (blocked at the A-V junction). In the majority of these patients, there is a downward and a right hand shift in the curve after an interpolated PVC. On other hand, the curves representing the sum H1 H2 + delta A1 H1 on function of A1 A2 were shifted upward and to the right in 12 of the 14 patients. This indicates inhibition which manifests itself not only by an ERP increase but also by an A2 H2 increase.

[Aneurysm of the interauricular septum by hernia of Vieussens' valve, and suspected coronary embolism]. / Anévrysme de la cloison inter-auriculaire par hernie de la valvule de Vieussens et suspicion d'embolie coronaire.

During the hemodynamic evaluation of a young patient with heart failure whose electrocardiogram showed sequels of anterior necrosis, an aneurysm of the fossa ovalis was seen at cineangiography. Selective coronary angiography showed an interruption of filling of the anterior interventricular artery just distal to the branching of the first septal artery: it raised therefore the possibility of the embolic origin of that myocardial infarction. In connection with this case study, angiographic aspect, pathogenesis and the embolic role of the aneurysm of the fossa ovalis were discussed.

[The insertion of permanent pacemaker leads via the retro-pectoral veins (author's transl)]. / Mise en place des sondes de stimulation cardiaque permanente par les veines rétro-pectorales.

When it is not possible to use the cephalic vein for the insertion of a permanent pacemaker wire, the veins situated below the clavicular head of the pectoralis major, close to the lateral border of its upper part, can be used. This is possible in 87.6% of cases. The use of this approach is associated with a lower reoperation rate than the cephalic vein way.

[Paradoxical atrioventricular block within the bundle of His]. / Bloc auriculo-venticulaire paradoxal intrahisien.

We have been able to record an atrio-ventricular block dependent upon bradycardia, but also no tachycardia, in a patient of 76 who presented with syncopal attacks. The basal electrocardiogram showed no significant delay in atrio-ventricular or intraventricular conduction. Intracavitary electrophysiological investigation allowed us to localise the site of this block in the main trunk of the bundle of His; we also established, under basal conduction conditions, a first degree block with an exactly similar relationship to the duration of the preceding diastole.

[Electrocardiagraphic changes of Prinzmetal's angina type in the acute phase of myocardial infarct]. / Altérations électrocardiographiques de type angor de Prinzmetal en phase aiguë d'infarctus du myocarde.

The authors have studied the frequency and severity of anginal attacks of the Prinzmetal type coming on during the acute phase of a myocardial infarction in 13 patients. They have occurred in 5.50% of cases (anginal attacks of all types occurring in 18.34% of cases). The severity of these attacks is shown by their clinical features: the multiplicity of the attacks, the high incidence of arrhythmias, the difficulties encountered with medical treatment. This also confirmed by the enzyme studies: when the curve of myocardial creatinine kinase release is drawn, there is seen to be an extension of the lesion in 2/3 cases, whereas the electrocardiograph does not show this up.

[Type A Wolff-Parkinson-White syndrome associated with left bundle-branch block. Electrocardiographic, vectorcardiographic, and endocavitary electrophysiological study]. / Syndrome de Wolff-Parkinson-White du type "A" associé à un bloc de la branche gauche. Etude électrocardiographique, vectorcardiographique et électrophysiologique endocavitaire

The rate association of a "type A" W.P.W. syndrome with a left bundle branch block gives a characteristic electrocardiographic picture:--the left bundle branch block is partially masked, the delay in the basial region of the left ventricle being in part cancelled by pre-excitation--the features of the W.P.W. syndrome are also modified, since the ventricular axis is corrected by the left bundle branch block. The electrocardiographic tracings taken during the various tachycardias and during treatment for arrhythmia, together with the intra-cavitary recordings allow a precise diagnosis to be made. In this case, vectocardiography was particularly useful as it gave a clear demonstration of the median delay of the ventricular loop, the only pathognomic feature of left bundle branch block, during a period when the left bundle of Kent was functioning.

[Bi-directional tachycardia of infrabundle of his origin. Arguments for reciprocal rhythm]. / Tachycardie bi-directionnelle d'origine infrahissienne. Arguments en faveur d'un rythme réciproque

A new case of bi-directional tachycardia is reported. Intracavitary recordings show that the site of the disorder lies below the main trunk of the bundle if His. Analysis of the surface electrocardiogram and of electrical stimulation has led to a number of arguments for the hypothesis of a reentry circuit which uses the right branch in the reverse direction, and then the anterior and posterior sub-branches alternately in the normal direction. The recurrent attacks of tachycardia can be prevented by permanent ventricular stimulation at a rate above that which occurs between the attacks. However, the relief which this affords has not altered the prognosis of this arrhythmia, which remains very poor.

[Resistance and facilitation gradient in synchronized cardiac stimulation in the dog]. / Gradients de résistance et de facilitation en stimulation cardiaque synchronisée chez le Chien

Electrical stimulation synchronized on spontaneous or paced cardiac rhythms demonstrates, in dogs : 1) phenomena of intermittent capture (I.C.), and intermittent loss (I.L.) of control, at all moments in the idastole ; 2) constant lowering of Excitability Threshold (E.T.) and Pacing Threshold (P.T.). These experiments confirm the existence of Resistance Gradients (including I.C. and I.L. phenomena) and Facilitation Gradients (measuring E.T. and P.T. lowerings). These gradients -- that we previously described in human pacing -- are parameters of the cardiac excitability.