05957956 is referenced by 297 patents and cites 30 patents.

A capacitor-discharge implantable cardioverter defibrillator (ICD) has a relatively smaller mass of less than about 120 grams. The smaller mass of the ICD is achieved by selecting and arranging the internal components of the ICD to deliver a maximum defibrillation countershock optimized in terms of a minimum physiologically effective current (I.sub.pe), rather than a minimum defibrillation threshold energy (DFT). As a result of the optimization in terms of a minimum effective current I.sub.pe, there is a significant decrease in the maximum electrical charge energy (E.sub.c) that must be stored by the capacitor of the ICD to less than about 30 Joules, even though a higher safety margin is provided for by the device. Due to this decrease in the maximum E.sub.c, as well as corollary decreases in the effective capacitance value required for the capacitor and the net energy storage required of the battery, the overall displacement volume of the ICD is reduced to the point where subcutaneous implantation of the device in the pectoral region of human patients is practical. The size of the capacitor is reduced because the effective capacitance required can be less than about 125 .mu.F. By optimizing both the charging time and the countershock duration for the smaller maximum E.sub.c, the size of the battery is reduced because the total energy storage capacity can be less than about 1.0 Amp-hours. In the preferred embodiment, the charging time for each defibrillation countershock is reduced to less than about 10 seconds and the pulse duration of the countershock is reduced to less than about 6 milliseconds.

Title
Implantable cardioverter defibrillator having a smaller mass
Application Number
263257
Publication Number
5957956
Application Date
November 3, 1997
Publication Date
September 28, 1999
Inventor
Charles U Smith
Minnetonka
MN, US
Kenneth M Anderson
Bloomington
MN, US
Theodore P Adams
Edina
MN, US
Mark W Kroll
Minnetonka
MN, US
Agent
Brad Pedersen
Assignee
Angeion
MN, US
IPC
A61N 1/18
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