Implantable pacemaker cardioverter defibrillators are now available wi
th biphasic waveforms, which have been shown to markedly improve defib
rillation thresholds (DFTs). However, in a number of patients the DFT
remains high. Also, DFT may increase after implantation, especially if
antiarrhythmic drugs are added. We report on the use of a subcutaneou
s patch in the pectoral position in 15 patients receiving a transvenou
s defibrillator as a method of easily reducing the DFT. A 660-mm(2) pa
tch electrode was placed beneath the generator in a pocket created on
the pectoral fascia. The energy required for defibrillation was lowere
d by 56% on average, and the system impedance was lowered by a mean of
25%. This maneuver allowed all patients to undergo a successful impla
nt with adequate safety margin.