Vp suppression algorithm and second degree AV block

Tracing
N° 2
Manufacturer Biotronik Device PM Field Pacing Modes
Patient
  • 72-year-old man
  • Evia DR-T pacemaker (Biotronik) for paroxysmal atrioventricular block
  • Vp-suppression algorithm
Graph and trace
  • Spontaneous atrial and ventricular rhythm
  • First dropped P wave
  • Second dropped P wave
  • Third dropped P wave
  • Switch to DDD mode (second degree AV block)
Comments
  • The tracing shows a switch from AAI to DDD for paroxysmal second degree AV block
  • There are 4 switching criteria from AAI to DDD corresponding to the different degrees of atrioventricular block
  • First-degree AV block criterion: the pacemaker switches to DDD mode when 2 consecutive atrial events (spontaneous or paced) are conducted with an AS-VS or AP-VS delay exceeding 450 ms (non programmable)
  • Second-degree AV block criterion: the pacemaker switches to DDD mode when X  out of 8 atrial events are dropped; this is the only programmable parameter (1/8, 2/8, 3/8, 4/8)
  • Third-degree AV block criterion: the pacemaker switches to DDD mode when 2 (non programmable) consecutive spontaneous or paced atrial activities are dropped
  • Pause criterion: the pacemaker switches to DDD mode when the interval between 2 sensed ventricular activations exceeds 2 seconds (non programmable)