European Heart Journal (1993) 14,492-498 In-hospital experience with multiprogrammable implantable antitachycardia/antifibrillation devices

Multiprogrammable, automatic internal defibrillators with (n = 45) and without (n —15) antitachycardia pacing features were implanted in 60 consecutive patients with refractory, malignant ventricular tachycardia ( VT) (n = 42) or fibrillation ( VF) (n = 18). Left ventricular (L V) ejectionfraction wasreduced to 39 % ± 12 % as a result of structural heart disease in 56 patients. The complexity of the systems caused no additional risks to the surgical procedure or postoperative manage-ment. VT / VF detection parameters were individually adjusted to the arrhythmia type (detection cycle length 323 ± 40 ms in patients with VF vs 405 + 40 ms for VT patients, P<0-05) and incidence (longer detection periods if frequent non-sustained VT was also present). Shock energy was reduced in patients with VT as compared to VF(11Jvs 24J, P<005). Antitachycardia pacing was activated in 19/28 (68%) patients with well tolerated VT. Signal, telemetry, as detected by the device, combined with programmability allowed the device to be checked for correct decisions (these were inappropriate in four patients in three of whom corrections were non-invasive) prior to discharge. In conclusion, in the automatic tachy-arrhythmia control devices we studied, programmability andflexibility appeared to be clinically safe and useful. Prolonged observation periods are required, however, to evaluate the true clinical safety and persistent efficacy of device programmability andflexibility