One of the priority objectives of ICD programming is to minimize the risk of an electric shock while not jeopardizing patient safety. A large number of rapid tachycardias diagnosed in the VF area are organized, monomorphic and are therefore likely to be reduced by an antitachycardia pacing burst. While the effectiveness of an electric shock in terminating rapid ventricular arrhythmia is indisputable, a shock is nonetheless painful and significantly increases energy consumption. The delivery of several successive shocks in a same patient is therefore associated with a risk of premature wear of the batteries, with a significant lowering of the quality of life of the patients (many described cases of depression or anxiety induced by a series of shocks) as well as an altered prognosis (mortality risk increasing in parallel with the number of delivered shocks). The PainFree Rx trial (prospective, randomized, multicenter study) showed that a single antitachycardia pacing sequence (8 beats at 88%) allowed terminating a large proportion of fast tachycardias in the VF zone and provided a significant benefit in terms of quality of life, by reducing the number of shocks delivered without increasing the risk of sudden death, syncope or accelerated tachycardia. Thus, delivering an antitachycardia pacing sequence in the VF zone often seems to be effective, painless, reduces battery wear and improves the quality of life and should therefore be offered as a first-line option for this range of tachycardias (< 250 beats/minute). It is now recommended to program at least one antitachycardia pacing sequence for tachycardias up to a rate of 230 beats/minute by favoring the burst as opposed to ramp therapy (at least 8 stimuli with 88% coupling).

It is possible to program a burst in the VF zone, the one-shot ATP, which allows a painless treatment of VT while preserving part of the charge. The one-shot ATP is only delivered if the ventricular rhythm sensed in the VF area is considered to be regular (stability threshold at 12%). When the VF counter is full, the device delivers an antitachycardia pacing sequence (by default a burst with 8 stimuli at 85% of the tachycardia cycle length). As soon as the burst is delivered, the capacitors automatically begin charging. If the burst is successful (3 out of 4 intervals classified as VS or VP), the charge is interrupted. Otherwise, the charge continues and the shock is delivered. The duration of the charge is therefore short if the ATP is effective. This allows avoiding a shock (painful for the patient and a likely factor of poor prognosis) at the price of a limited energy consumption (partial and rapidly interrupted charge). It is possible to program the type of ATP (burst or ramp) and the various parameters of a standard sequence (number of intervals, etc). The one-shot ATP is automatically de-programmed after 4 consecutive unsuccessful attempts.