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Maximum output shock in the VT zone - Incepta VR

Patient

  • 51-year-old man implanted with an Incepta single-chamber defibrillator

 

Summary

  • episode classified in the VT zone
  • 3 bursts + 3 ramps + 1 shock of 41 Joules

 

EGM layout

  1. probable ventricular tachycardia (clear change in morphology on the shock channel)
  2. at the end of the duration, a burst of 10 complexes at a fixed rate
  3. ineffective burst and ongoing arrhythmia
  4. second burst
  5. third burst
  6. first ramp
  7. second ramp
  8. third ramp
  9. next therapy is an electric shock; capacitor charging begins
  10. 41 Joule electric shock delivered on the second rapid ventricular cycle (2/3 rapid cycle criterion verified) at the end of the diversion window
  11. effective shock


Take home message

  • this plot illustrates the other option for programming the amplitude of the first shock in the VT zone
  • empirical programming of a first shock of maximum amplitude reduces the risk of pro-arrhythmogenic effects and increases the probability of terminating VT on the first attempt, thereby minimizing the number of shocks delivered and increasing the probability of terminating AF if the shock is inappropriate

 

Example of programming in the VT zone with therapies of increasing aggressiveness; burst then ramp then shock (maximum amplitude from the outset); 8 shocks can be programmed for the VF zone, 6 shocks for the VT zone and 5 shocks for the VT-1 zone.

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