[Endocavitary His bundle fulguration in the treatment of resistant supraventricular arrhythmia]. / Fulguration endocaviataire du faisceau de His dans le traitement des troubles du rythme supraventriculaires rebelles.

Nine patients aged 47 to 74 years underwent endocavitary destruction of the bundle of His because of paroxysmal arrhythmias resistant to medical therapy. Four patients had paroxysmal atrial fibrillation, 2 had paroxysmal atrial flutter, 1 had reentrant atrial tachycardia, 1 had paroxysmal atrial tachycardia and 1 had an intranodal reentrant tachycardia. One patient had already undergone "surgical ablation" of the His bundle without success. A tripolar or bipolar catheter was introduced via the femoral vein and the His potential localised by bipolar and then unipolar recordings. The lead with the greatest His potential was connected to an external defibrillator and the other pole connected to a metal plaque positioned under the patient's left shoulder. An electrical shock of 200 to 400 joules was administered, in some cases repeatedly. Eight of the 9 patients developed complete atrioventricular block after the shock. This was only temporary in 3 cases, necessitating another shock in 2 cases; the procedure was not repeated in the 3rd case. After 30 minutes of persistent AV block a pacemaker was implanted; 7 of these 8 patients had VVI and I patient (intranodal reentry) DDD pacing. The follow-up period ranges from 1 to 18 months. None of the patients have had symptoms of paroxysmal arrhythmia; in the long-term, there was one initial failure. Of the other 8 cases, 4 remain in complete AV block, 2 have 2nd degree and 21st degree AV block. Three patients have associated antiarrhythmic therapy with quinidine or verapamil. No side effects were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

[Electrophysiological properties of acute intravenous sotalol in man]. / Etude des propriétés électrophysiologiques du sotalol administré par voie veineuse de façon aiguë chez l'homme.

The electrophysiological properties of of 0,6 mg/Kg SOTALOL administered intravenously were studied in 15 subjects aged between 32 and 81 years. The following parameters were recorded: sinus rate (SR), corrected sinus node recovery time (SNRT), sinoatrial conduction time (SACT), PA interval, right atrial effective refractory period (ERP), right atrial functional refractory period (FRP), AH interval at rest, at 100 bpm, Luciani-Wenckebach point (LWP), AV node ERP and FRP, HV interval, His-Purkinje ERP, right ventricular ERP, corrected QT interval. At this dosage, intravenous SOTALOL displays two types of behaviour: --That common to the betablocker drugs: slowing SR by 16%, increasing the AV nodal conduction, increasing the AH interval at rest (5%), at 100 bpm (23%), increasing AV nodal ERP (26%) and FRP (20%), decreasing the LWP (18%). --Other properties: increasing intraatrial PA interval (3%), increasing right atrial ERP (II%), FRP (I7%), increasing right ventricular ERP (8%), increasing His-Purkinje ERP (when measurable) (about 6%), no change in corrected QT interval. At this dosage, SOTALOL exhibits electrophysiological behaviour similar to drugs in Class III (Touboul): those with a "wide electrophysiological spectrum".

[Wolff-Parkinson-White syndrome after 50 yars of age. Clinical and electrophysiological data]. / Le syndrome de Wolff-Parkinson-White après cinquante ans. Données cliniques et électrophysiologiques.

The Wolff-Parkinson-White syndrome is usually observed in young people and is much rarer in patients over 50 years old. This fact may be explained by the demise of a certain number of patients before the age of 50 and/or a change in the clinical features of the syndrome with age and/or of the electrophysiological properties of the normal and accessory conduction pathways. To test the latter hypothesis, the clinical and electrophysiological data of 15 patients over 50 years old with the Wolff-Parkinson-White syndrome (Group I) were compared with that of 10 patients under 30 years old with the same syndrome (Group II). The same protocol of electrophysiological investigation was used in both groups of patients. The results showed a significant difference (p < 0.001) between the two groups in the incidence of associated cardiac disease. This was more common in Group I (1 4 out of 15 patients) than in Group II (2 out of 10 patients). The cardiothoracic ratio was significantly higher in Group I (p < 0.01). The two groups also differed in the age at which tachycardia first occured. 9 out of 11 patients in Group I only had symptoms after thirty years. On the other hand, there was no significant difference in the types of tachycardia and the frequency of attacks. There was no significant difference in QRS, PR, AH, HV intervals, in the ventriculo-atrial conduction time and the effective refractory periods of the atrium, right ventricle or atrio-ventricular node. There was no significant difference in the anterograde and retrograde refractory periods of the accessory pathways between the two groups. Reciprocating tachycardia, initiated by electrical stimulation in 7 patients in Group I and 6 patients in Group II, was conducted anterogradely to the ventricles through the normal pathway and retrogradely to the atria through the the accessory pathway. This study suggest that age-related changes in the electrophysiological properties of the accessory are not an important prognostic factor in the Wolff-Parkinson-White syndrome.

[Auriculo-Hisian conduction of patients with bundle branch block. Clinical significance]. / La conduction auriculo-hissienne des malades porteurs d'un bloc de branche. Signification clinique.

The clinical and electrophysiological data in 52 consecutive patients with bundle branch block and followed-up for an average period of 20.8 +/- 10.4 months was reviewed. The patients were divided into two groups: Group A with normal AH intervals (36 patients) and Group B with prolonged AH intervals (16 patients). These two groups differed in age, the average being higher in Group B (p < 0.05), in history of syncope (more common in Group A: p < 0.01) and in the duration of PR interval (p < 0.05). On electrophysiological investigation the Wenckebach point was lower in Group B (118 +/- 29 ms) than in Group A (160 +/- 33) (p < 0.001). The effective right atrial refractory period was significantly longer in Group B (321 +/- 111 ms) than in Group A (246 +/- 59 ms) (p < 0.05). The effective refractory period of the atrioventricular node was also significantly longer in Group B (492 +/- 190 ms) than in Group A (333 +/- 125 ms (p < 0.05). On the other hand, there was no significant difference in the HV interval or in the number of patients managed by permanent pacing.

Pacing-induced alternate Wenckebach periods: incidence and clinical significance.

Alternate Wenckebach periods have been defined as episodes of 2:1 atrioventricular (AV) block in which conducted P waves exhibit progressive PR prolongation until two or three successively blocked P waves. Ocurrence of this phenomenon during atrial pacing has been established. Thirty-six patients were studied and right atrial pacing was achieved at increasing rates up to 350 beats/min in order to induce alternate Wenckebach periods. His bundle recordings were obtained in every patient. The patients were subdivided into three groups according to the AV nodal conduction time (AH interval): normal AH (75-130 ms) was present in 17 patients, short AH (70 ms) in 13 patients and prolonged AH (130 ms) in eight patients. Alternate Wenckebach periods were observed in 29 patients (80.5%). In every patient alternate Wenckebach periods occurred at the AV node level. Atrial pacing failed to induce alternate Wenckebach periods in seven patients, six of whom belonged to the short AH group. In four patients 3:1 block never appeared because of block at the atrial level. Two patients presented 2:1 and 3:1 infrahissian block without significant AH prolongation. The remaining patient developed atrial fibrillation. Alternate Wenckebach periods were observed in six of nine patients after intravenous atropine. This study suggests: 1. pacing-induced alternate Wenckebach periods at the AV node level are a physiologic phenomenon; and 2. total or partial bypass (or accelerated AV conduction) atrial refractoriness or vulnerability or block at a lower level may prevent its occurrence.

[Importance of sequential atrioventricular pacing in obstructive myocardiopathy with atrioventricular block]. / Intérêt de la stimulation séquentielle auriculo-ventriculaire dans la myocardiopathie obstructive avec bloc auriculo-ventriculaire.

A case of atrioventricular block (AVB) complicating hypertrophic obstructive cardiomyopathy is reported and analysed with respect to the results of cardiac catheterisation. The installation of 2nd degree AVB was associated with an increase of the intraventricular pressure gradient from 36 to 128 mmHg. This aggravation was related to the lenghtening of diastole which lowered the aortic diastolic pressure and allowed a more forceful ventricular contraction with a reduction in the calibre of the intraventricular stenosis. The sudden lenghtening of diastole also led to an increased contractility of the following systole. In complete AVB the increased gradient was related to a reduction in ventricular volume secondary to the loss of atrial systole. The 33 mmHg pressure gradient disappeared when spontaneous atrial systole or an atrial systole provoked by sequential atrioventricular pacing preceded ventricular contraction. Sequential atrioventricular pacing would seem to be the most appropriate pacing technique in hypertrophic obstructive cardiomyopathy complicated by complete AVB.

[Paroxysmal supraventricular tachycardia with complete atrio-ventricular block or dissociation]. / Tachycardies supraventriculaires paroxystiques avec bloc auriculoventriculaire complet ou dissociation auriculoventriculaire complète.

Recent studies have shown the high incidence of concealed Bundles of Kent in the reentry circuits of paroxysmal supraventricular tachycardia. Arguments in favour of the nodal or junctional level of reentry were observed in supraventricular tachycardia with complete atrioventricular dissociation. Two such cases under went electrophysiological investigation. In the first case, tachycardia was terminated by a complete infrahisian block. However, during atrioventricular dissociation, tachycardia could be initiated by a single atrial stimulus after an increased nodal conduction time and terminated by a single atrial stimulus or cardiac message. In the second case the supraventricular tachycardia presented with complete atrioventricular dissociation due to a retrograde ventriculo-atrial block. Atrial stimulation at progressively higher rates and premature atrial extra stimuli initiated the tachycardia but could not terminate it, so confirming the non-participation of the atrium in the reentry circuit. These two cases suggest that the ventricle (case I) and the atrium (case II) are not indispensable links in junctional or nodal reentry circuits. Case II was suggestive of a common initial pathway developing retrograde unidirectional block during tachycardia.

Serum elastase inhibitors in cardio-vascular diseases.

Serum elastase inhibiting capacity was measured in three groups: 150 control subjects, 38 hospitalized children without cardiovacular diseases and 202 hospitalized patients suffering from cardiovascular diseases. The values obtained were 53% in control adult subjects and 79% (range 45--90%) in the hospitalized patient groups. The highest levels were recorded at the acute phase of myocardial infarction. The levels of alpha 1-antitrypsin (alpha1-AT) and alpha 2-macroglobulin (alpha2-M) were determined by radial immunodiffusion technique for various levels of inhibitory power. No correlation was found between the inhibitory power levels and the alpha1-AT and alpha2-M levels. This study suggests that other proteins may intervene in the inhibition process of elastolysis.