Switch for first degree atrioventricular block during exercise

Tracing
N° 2
Manufacturer Microport CRM Device PM Field SafeR mode
Patient
  • 68-year-old man
  • Kora 100 DR pacemaker (Microport CRM-Sorin) for sinus dysfunction
  • SafeR algorithm
  • Programmed value for long PR max 350 ms, long PR min 250 ms
  • Episodes of switch to DDD for first degree AV block (AVB1) during exercise
Graph and trace
  • Atrial pacing with ventricular sensing (AR) at the maximal sensor rate (120 bpm)
  • After 6 consecutive cycles with AR interval longer than the programmed value during exercise: switch to DDD
  • Atrial and ventricular pacing
Comments
  • 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)
  • Exercise is defined by the device as a heart rate > a value depending on the programming of the lower rate limit
  • When the programmed lower rate limit is ≤ 70 bpm, the onset of exercise is defined by a rate > 100 bpm and the end of exercise rate by a rate < 90 bpm
  • When the programmed lower rate limit is ≥ 75 bpm, the onset of exercise is defined by a rate > lower rate limit + 30 bpm and the end of exercise rate by a rate < lower rate limit + 20 bpm
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