Switch for first degree atrioventricular block

Tracing
N° 1
Manufacturer Microport CRM-Sorin Device PM Field SafeR mode
Patient
  • 65-year-old man
  • Reply DR pacemaker (Microport CRM-Sorin) for sinus dysfunction
  • SafeR algorithm
  • Programmed value for long PR 350 ms (AR 450 ms)
  • Episodes of switch to DDD for first degree AV block (AVB1)  recorded in AIDA (memory of the device)
Graph and trace
  • Atrial pacing with ventricular sensing (AR)
  • AR intervals between 367 and 406 ms (less than the programmed value)
  • Prolongation of the AR intervals (> 450 ms)
  • After 6 consecutive cycles with AR interval > 450 ms, switch to DDD (vertical line)
  • Atrial and ventricular pacing
Comments
  • The device switches to DDD when PR or AR intervals are longer than the programmed maximum programmable value during 6 consecutive cycles
  • Only the long PR (sensed atrial activity) interval is programmable
  • The long AR value (paced atrial activity) = long PR + 100 ms
  • The AVB I (first degree AV block) criterion can be programmed to: rest + exercise (the device may switch to DDD during rest and exercise phases) or to exercise only (the device may switch to DDD during exercise phase only)