title: Rise in chronic defibrillation energy requirements necessitating implantable defibrillator lead system revision.
abstract: The chronic defibrillation energy requirement (DER) is believed to remain clinically stable in patients with defibrillators. Six patients (two with an epicardial and four with a nonthoracotomy system) were identified with a rise in their chronic DER, which eliminated a 10-J safety margin, thus necessitating a defibrillator lead system revision. The mean increase in DER was 14.7 +/- 4 J and was discovered at a mean of 16.0 +/- 18 months (range 2-41) following implantation. Management included placement of a defibrillator with a biphasic waveform, placement of an additional defibrillation electrode, or both. At 2 months following revision of the defibrillation system, a 10-J DER safety margin was present in each patient. In some patients, there is a progressive increase in the chronic DER with elimination of a 10-J safety margin necessitating revision of the defibrillation system. Routine reevaluation of the chronic DER, therefore, is necessary to identify these patients.
authors.affiliation: Department of Internal Medicine, University of Michigan Hospitals, Ann Arbor 48109-0022, USA.
authors.forename: E G
authors.initials: EG
authors.lastname: Daoud
authors.forename: K C
authors.initials: KC
authors.lastname: Man
authors.forename: F
authors.initials: F
authors.lastname: Morady
authors.forename: S A
authors.initials: SA
authors.lastname: Strickberger
mesh_terms: D000368:Aged; D017147:Defibrillators, Implantable; D011211:Electric Power Supplies; D004594:Electrophysiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged