Abstract

Atrial fibrillation (AF) is one of the most common sustained cardiac arrhythmias found. Its treatment requires the use of a synchronised electrical shock or drug therapy. This paper describes a new form of electrical defibrillator that empioys a two-part, transdermal RF transformer to couple an on-off keyed 7.2 :MHz pulse to an implanted, passive receiver; this, in turn, . delivers a unipolar DC shock to the heart. Factors influencing the transformer's design are discussed and results from axial and lateral primary / secondary coil -displacement trials presented. In animal studies, cardioversion was 100 % successful with pulses of 100 V amplitude and 10 rns width. The implant is battery-free, which makes it an attractive and inexpensive alternative for the treatment ofAF.