Prevention of intra-atrial reentry by chronic atrial pacing.

The authors describe a case of so-called "intra-atrial reentry," associated with sinus node dysfunction. The spontaneous initiation of the tachycardia was always preceded by a sinus pause, and external atrial pacing prevented the appearance of tachycardia. Thus an atrial pacemaker was implanted, and after several months, the atrial dysrhythmias disappeared completely, despite interruption of the antiarrhythmic drugs.

[Ventricular tachycardia in bursts. Electrophysiological and therapeutical study].

22 patients with salvoes of ventricular tachycardia were investigated electrophysiologically and pharmacologically to determine the mechanism of the arrhythmia. The appearance of the ventricular complexes was suggestive of a septal origin. The arrhythmia appeared to occur and regress within precise limits of sinus rhythm.

[Ventricular arrhythmias and mitral valve prolapse. A study of 35 cases].

35 patients with mitral valve prolapse (MVP) underwent investigation by Holter monitoring with computerised analysis. Ventricular arrhythmias were observed in 70% patients with MVP. There does not seem to be a close correlation between the severity of the arrhythmia and the degree of prolapse.

[Intracorporeal cardiac pacemakers for refractory tachycardia (excluding atrial disease). Apropos of 18 cases].

The treatment of paroxysmal tachycardia by the use of permanent pacing to prevent or terminate attacks is discussed. The series comprises 18 patients with follow-up periods ranging from 1 to 12 years. In 6 cases the indication for pacing was atrial tachy-arrythmias favourised by bradycardia (5 of whom had vagally- induced atrial arrythmias).

Multilevel block in the atrioventricular node during atrial tachycardia and flutter alternating with Wenckebach phenomenon.

The electrocardiograms of 100 patients with rapid and regular PP intervals during atrial arrhythmias (because of atrial tachycardia or flutter, or pacing) were examined for periods of irregular atrioventricular conduction. This irregular conduction corresponds to an alternating Wenckebach phenomenon, of a type that can be determined from simple rules. The different types of conduction encountered in different patients and the changes seen in the same patient suggest that the atrioventricular node functions physiologically with 3 levels of sequential block.

Sustained intra-atrial reentrant tachycardia. Electrophysiologic study of 20 cases.

Twenty cases of sustained tachycardia due to intra-atrial reentry were investigated in patients aged 17 to 80 years (mean 47). The average frequency of the tachycardia was 128.6/min (extremes 95 and 180).

[Technical characteristics of a new computerized system for quantitative evaluation of cardiac arrhythmias (author's transl)].

The ATREC system is designed to carry out at sixty times real time the quantitative evaluation of arrhythmias in 24 hour magnetic tape recordings. A preprocessing unit eliminates the low frequency waves (P and T) and artefacts, and furnishes the computer (Mitra 15/35, 16 K words of core) with information on R-R interval, QRS duration, regular or irregular rhythm, bradycardia or pauses, transient to sustained tachycardia, and ventricular fibrillation. Extrasystoles are analyzed in terms of enlargement, number, coupling interval, bi or trigeminy, doublets or salvos.

[Quantitative evaluation of the efficacy of anti-arrhythmia agents in chronic ventricular arrhythmia].

The authors describe a computer system for the analysis of ventricular arrhythmias and its use in the evaluation of anti-arrhythmic drugs. Provided the arrhythmia is stable, this method allows an estimation of the onset and duration of action of the drug and gives guidelines for the choice of an appropriate drug regimen. Using this system, a comparison can be made between different drugs based on quantification of their efficacy.

[2 or 3 level blocks in the Tawara node during atrial tachycardia].

In atrial flutter (or paroxysmal atrial tachycardia), the ventricular response is dependant on the passage through 3 superposed zones of conduction in the Tawara node, the zone of decremential conduction being the central zone N. When the ventricular response is between half and a quarter of the atrial rate there are two possible explanations: type B alternate Wenckebach period (mobitz I block in the central zone N, 2/1 block at the nodo-ventricular junction) or type A alternate Wenckebach period (Mobitz I block in the central zone N and 2/1 block at the atrio-nodal junction). These two responses may alternate in the same patient depending on the drug therapy or vagal activity due to a phenomenon similar to the "GAP" phenomenon.

[The atrial arrhythmia syndrome of vagal origin].

Having observed 18 cases, the authors describe a syndrome of recurrent paroxysmal atrial arrhythmia which was very homogeneous from the clinical and ECG point of view. It was usually found in middle aged males, with no demonstrable underlying heart disease, whose disorder of intra-atrial conduction occurred during sinus rhythm. The condition developed slowly over the course of years towards a maximum incidence of several short daily attacks of an arrhythmia which alternated between an atrial fibrillation and atrial flutter.