[Value and limitations of diagnostic function of bradycardia of a ventricular pacemaker]

The indication for permanent pacing may be confirmed by a bradycardia counter in patients without ECG or Holter recording of the causal bradycardia. The algorithm was assessed in a multicenter register with the SORIN Theorema model. The activation of the device was programmed on a double hysteresis of 2 seconds with a programmable histogramme of detections and sensing and pacing counters. One hundred and forty five patients were recruited in 50 centers over 2 years: 89 men and 56 women aged 33 to 96 years (average 72 years), 87 of whom had no other obvious cardiac disease. One hundred and ten had typical syncopal episodes, 19 had atypical or minor syncopal attacks and 16 were asymptomatic, one with sinus node dysfunction and the others with pathological prolongation of the HV interval (> or = 70 ms) during endocavitary electrophysiological investigation. The mechanism of the bradycardia was considered to be infra-hisian in 62 patients who had HV intervals > or = 70 ms. This was also the probable mechanism in 20 others who had bundle branch block and typical syncope despite a HV interval < 70 ms and in 6 patients with bundle branch block and typical syncope who did not undergo electrophysiological investigation before implantation. Twenty one patients had sinus node dysfunction during electrophysiological investigation and 8 had a carotid sinus syndrome. The remaining 28 cases had transient syncope but no ECG changes or abnormality on electrophysiological investigation. Permanent pacing was proposed when an extracardiac origin of the syncope was excluded.(ABSTRACT TRUNCATED AT 250 WORDS)