Automatic Implantable Cardioverter Defibrillators: Surgical Approaches for Optimal Function

The automatic implantable car dioverter defibrillator (AICD) has significantly enhanced the treatment of malignant tachyarrhythmia but has complex requirements for contin uous function. Forty-nine patients (pts, ages nine to seventy-nine) from 377 pts studied for life-threatening tachyarrhythmias (13%) underwent AICD hardware placement during the first forty-eight months of clinical investigation. Access was dictated by (1) prior operative procedures (17 pts), (2) adequate sensing thresholds (12 pts), and (3) low thresholds (ie, s 15 watts) for successful defibrilla tion configuration (21 pts). Late com plications and morbidity (26 pts, 53%) have been the rule, the most common due to: (A) generator fail ures (15 pts), (B) patches or lead mal positions (4 pts), (C) inappropriate sensing from lead failures (3 pts), and (D) required explanations (leads only for 2 pts and units for 2 pts). There has been only 1 operative death among the 49 pts and none for the 21 revisions and generator changes (overall 1/70 procedures, 1.4%). However, survivals at one, two, and three years were 82%, 56%, and 40% respectively with the majority of late deaths attributed to congestive heart failure (CHF). In summary, (1) AICD morbidity remains frequent but can be mini mized. Incidental placement should be avoided owing to associated mor bidity (explantation). (2) Optimal configurations usually require (a) ep icardial access, (b) patches directed at the ventricular focus for lower de fibrillation thresholds, (c) generator implantation adjusted for habitus, growth in children, and frequent generator failure. (3) Long-term sur vival has been poor in patients with associated CHF