Induction of ventricular fibrillation
INDUCTION OF VENTRICULAR FIBRILLATION
Three means are available in Sorin devices to induce VF: shock‑on‑T wave and HF Burst.
T-wave shock
A low energy shock is delivered during the ventricular vulnerable period to induce a ventricular arrhythmia (most often VF). A ventricular stimulation sequence, at a fixed rate is followed by the delivery across the electrodes, of a low-energy electrical shock during the ventricular vulnerable period. The delivery of the shock requires the prior charge of the capacitors.
s1 pulses: number of s1 pulses which will constitute the burst; nominal 6
s1-s1 : coupling interval to first s1 pulse and between s1 pulses: nominal 410 ms;
Pacing mode is VVI at the maximum programmable amplitude and pulse width; 7.5V @ 1 ms.
s1-T: Coupling interval from the last s1 to the T-wave shock pulse: nominal 310 ms; [60 ; 500]
VF Induction: Instructs the defibrillator to deliver the burst. Once pressed, this button changes to Cancel.
Cancel (VF): Stops VF induction if it is not complete and restarts the defibrillator automatic arrhythmia detection and therapy. Once the induction is completed, automatic arrhythmia detection restarts and therapies are applied as programmed.
30 Hz pacing
A salvo of rapid pacing (alternating current) is delivered to induce an arrhythmia (VT or VF). The defibrillator provides a 30 Hz pacing burst (33 ms period) in VOO mode at the maximum programmable amplitude and pulse width; 7.5V @ 1 ms. The duration (in seconds) of the burst for VF induction is programmable. Nominal 1 s; [1 ; 30]
Manual FV reduction
This procedure can be performed under local anesthesia. The operator programs VF therapies and sets shocks to OFF. Then, by pressing the Charge only button, the capacitors are charged to the energy of the first shock. A VF is then induced by using VF the induction button. The operator chooses when to deliver the therapy just after the patient has lost consciousness by using Enable Socks button.
