[Use of digitalis glycosides in severe disorders of intra-ventricular conduction]. / Utilisation des digitaliques en cas de troubles sévères de la conduction intra-ventriculaire.

The use of digitalis in severe disorders of intra-ventricular conduction is debatable, and some consider it contra-indicated. Once it had been shown that the latter attitude is at best based on contraversial theoretical arguments, two types of study were undertaken: 1. Nine patients with bilateral bundle branch block had intracavitary recordings made of the HV interval both before and for one hour after the administration of lanatoside C (0.8 to 1.6 mg). In no case was this interval found to be increased, indicating that there was no increase in the original conduction defect. 2. Thirty four patients with complete right bundle branch block and associated left antero-superior hemiblock were digitalised, and followed up for an average of 16 months; only 2 complete atrio-ventricular blocks occurred (5.9%). The risk of complete atrio-ventribular block occurring within a year (4.5% in our series) does not differ significantly from that in an identical control group of 38 patients with the same conduction defect, but who were not digitalised (6%). Three patients had a therapeutic overdose of digitalis with no observed increase in their atrio-ventricular block. The authors conclude that it is perfectly in order to digitalise a patient with a severe intra-ventricular conduction defect.

[Anti-arrhythmic effects of injectable amiodarone. Apropos of 100 cases]. / Les effets antiarythmiques de l'amiodarone injectable. A propos de 100 cas

The effects of amiodarone by injection have been studied in 100 patients. 50% of these patients were in cardiac failure. Amiodarone was given intravenously over 30 seconds in a dose of 300 mg; in 15 of the patients a further dose of 150 mg was given after ten minutes. Amiodarone was found to be particularly effective in the tachy-arrhythmias (90% successful) in which it brought about slowing (18 cases out of 30) or conversion (17 cases out of 30). Just as good results were obtained for the atrial tachycardias (90% success rate) and in the junctional tachycardias. This treatment is less effective for atrial flutter (50% successful) and for ventricular arrhyrthmia, in which the success rate was only 60%. It is possible to use the defibrillator after amiodarone has been administered. This drug is well tolerated, and no increase in cardiac failure has been noted in these patients. There does remain, however, the possibility of hypotension and perhaps of circulatory collapse, which is rapidly reversable; this is probably due to vasodilator activity. Intracavitary studies in 8 patients have shown that amiodarone causes slowing of sino-atrial and of atrio-ventricular conduction. Amiodarone may equally worsen a distal conduction defect. The uses for this anti-arrhythmic drug, which is particularly effective at the atrial level, are discussed in this paper.

Autonomic influences and cardiac conduction in patients with sinus node disease.

18 patients with sinus bradycardia (8 SB) and tachycardia-bradycardia syndrome (10 TBS) were investigated using various vagan reflex manoeuvres, atrial pacing (AP), pharmacological tests and His bundle (HB) recordings, to assess autonomic influences, sinus node function and atrioventricular (AV) conduction. Three types of responses (R) were defined as normal (N), supernormal (SN), poor autonomic (PA). Poor reflex responses to vagal manoeuvres, performed in 12 patients, have no statistical significance. MxCSRT at AP suppression was measured in 13 patients: it was normal (less than or equal to 500 msec) in 8 and increased (from 680 to 4,200 msec) in 5 patients with appearance of junctional escapes. Moreover, AP suppression revealed a sinoatrial block (SAB) in 1 patient with normal MxCSRT. Isoprenaline, administered intravenously (3-6 mug) in 9 patients, showed 4 NR, 3 PAR und 2 SNR (unusual sinus tachycardia, 1; atrial fibrillation, 1). Atropine (0.5-1 mg), used in 15 patients, revealed 5 PAR and 1 SNR. Prostigmine (0.5 mg), used in 11 patients, induced 6 NR and 5 PAR. Lanatosid C (0.08 mg), administered in 16 patients, showed 10 NR, 5 PAR and 1 SNR. Finally, ajmaline (100 mg), given in 13 patients, revealed 5 junctional rhythms and one 2:1 SAB. HB recorded in 17 patients showed an increase of AH interval (greater than 140 msec) in 5 patients and a slight increase (60 msec) of HV interval in 2 patients. Three patients developed 2nd-degree AV block at paced rates greater than or equal to 110/min. Abnormal responses at AP suppression and reduced drug responses were noted in 5 patients suffering from Adam-Stokes attacks; a permanent pacemaker was inserted in 4 of these 5 patients. In conclusion, provocative tests, in 18 patients with SB or TBS, suggest a diffuse process disease involving the autonomic function of both sinus node and AV junction (11 patients) and the AV system (6 patients). These immediate results must be correlated with histological findings in the conduction system, as shown in one of our cases previously reported.