[Spontaneous cardiac rhythm in patients wearing cardiac stimulators]

Cutaneous electrical stimulation allows inhibition of permanent on-demand cardiac pacemakers. The evolution of the spontaneous cardiac rhythm was studied, using this technique of inhibition in 164 patients paced for 4 to 16 years. At implantation, 117 patients (70 p. 100) had atrioventricular block, 45 patients (27 p. 100) had sinoatrial dysfunction and 2 patients had a carotid sinus syndrome. Of these 164 patients, 153 were symptomatic. Three groups were distinguished: - 41 patients (25 p. 100) with a spontaneous ventricular rhythm at each check-up; - 75 patients (46 p. 100) with an underlying ventricular rhythm recorded when the pacemaker was inhibited by cutaneous electrical stimulation; - 48 patients (29 p. 100) with no underlying ventricular rhythm during 3 successive inhibitions of their pacemakers of 3 to 4 seconds duration on each occasion. All these patients had atrioventricular block at implantation; none had sinoatrial disease. In conclusion, disease of the atrioventricular conduction pathway, contrary to sinoatrial disease, leads to a prolonged absence of the spontaneous ventricular activity. This seems to be related to a longer survival of patients without associated pathology, and also suggests a degenerative cause of the atrioventricular block.