Previous generations of
implantable cardioverter defibrillators (ICDs) required invasive electrophysiological testing to assess
defibrillator function. Newer third-generation ICDs include the capability for performing noninvasive programmed stimulation (
NIPS) and may reduce the need for invasive studies to assess
tachycardia recognition and antitachycardia
therapy algorithms. The effectiveness of ICD-based
NIPS for the induction of ventricular arrhythmias has not, however, been formally assessed. Third-generation ICDs were implanted in 79 patients, who underwent a total of 166 postoperative
defibrillator tests.
NIPS with rapid ventricular pacing was performed in all patients in an attempt to induce
ventricular fibrillation. In patients with prior sustained uniform
ventricular tachycardia, programmed stimulation with up to three extrastimuli was performed in order to attempt to initiate the clinical ventricular tachcardia.
Ventricular fibrillation was induced with
NIPS in 146 of 166 studies (88%).
Ventricular tachycardia was initiated with
NIPS in 104 of 123 studies (85%). The type of
defibrillator and the use of endocardial or epicardial rate sensing/pacing leads did not influence the efficacy of
NIPS.
NIPS with third-generation ICDs is generally effective at inducing
ventricular fibrillation and clinically relevant
ventricular tachycardias, and reduces the need to perform invasive electrophysiological testing following device implantation. In a minority of patients temporary transvenous pacing
catheters must still be used to facilitate
arrhythmia induction.