A PATCH IN THE PECTORAL POSITION LOWERS DEFIBRILLATION THRESHOLD

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.