Importance

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Abstract

A shocking circuit is provided for use in an ICD for generating rounded multi-step defibrillation shocking pulse waveforms having reduced voltage peaks to minimize pain within a patient receiving the shocking pulse. The shocking circuit includes a set of capacitors, a resistive-capacitive (RC) filter, and low pain waveform control unit for selectively discharging the capacitors through the RC filer to generate the rounded pulse waveform. In one example, a pair capacitors are provided for generating a two-step pulse. The low pain waveform control unit initially discharges the capacitors in parallel to generate a first step of the pulse waveform while periodically shunting a portion of charge through the RC filter to reduce peak voltage. The low pain waveform control unit then discharges the capacitors in series to generate a second step of the pulse waveform while also periodically shunting a portion of charge through the RC filter to reduce peak voltage. With this circuit arrangement, a rounded, multi-step waveform can be readily generated for use within an ICD without requiring a high voltages or large capacitors. The shocking pulse itself is generated so as to approximate an input rounded waveform having an initial portion that increases monotonically to a final rounded peak, then decreases sharply.

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First Claim