Current truncated waveform defibrillator

Claim 3

The method of claim 1 in which the predetermined amount is less than about 40 Amperes.

Claim 4

The method of claim 1 in which the predetermined amount is less than about 30 Amperes.

Claim 5

The method of claim 1 in which, the predetermined amount is less than about 25 Amperes.

Claim 6

The method of claim 1 in which the predetermined amount is less than about 20 Amperes.

Claim 7

An implantable cardioverter defibrillator apparatus, the implantable cardioverter defibrillator apparatus being a self-contained human implantable device for treating cardiac arrhythmias that is electrically connected to at least two implanted discharge electrodes located in a human patient, the at least two implanted discharge electrodes having an effective resistance that is variable dependent upon the at least two implanted electrodes defining a discharge pathway therebetween and a physiological condition of the human patient across the discharge pathway, the apparatus comprising: (a) storage means electrically connected to the two or more implanted electrodes for storing an electrical charge to be delivered to the two or more implanted electrodes; (b) sensing means for sensing a cardiac arrhythmia in the human patient; (c) power source means for charging the storage means to a voltage; and (d) discharge means for selectively discharging the storage means in response to the sensing of the cardiac arrhythmias to deliver the electrical charge as a countershock that is current truncated such that the countershock has a peak current less than a predetermined amount regardless of the effective resistance value of a discharge pathway into which the countershock is delivered.

Claim 8

An implantable cardioverter defibrillator apparatus, the implantable cardioverter defibrillator apparatus being a self-contained human implantable device for treating cardiac arrhythmias that is electrically connected to at least two implanted discharge electrodes located in a human patient, the at least two implanted discharge electrodes having an effective resistance that is variable dependent upon the at least two implanted electrodes defining a discharge pathway therebetween and a physiological condition of the human patient across the discharge pathway, the apparatus comprising: (a) storage means electrically connected to the two or more implanted electrodes for storing an electrical charge to be delivered to the two or more implanted electrodes; (b) sensing means for sensing a cardiac arrhythmia in the human patient; (c) power source means for charging the storage means to a voltage; and (d) discharge means for selectively discharging the storage means in response to the sensing of the cardiac arrhythmias to deliver the electrical charge as a countershock that is current truncated such that the countershock has a peak current less than a predetermined amount regardless of the effective resistance value of a discharge pathway into which the countershock is delivered.

Claim 9

The system of claim 6 in which the discharge means comprises a non-linear current truncation means electrically connected in series between the capacitor means and the two or more discharge electrodes.

Claim 10

The system of claim 7 further comprising a waveform switching means electrically connected in series between the non-linear current truncation means and the two or more discharge electrodes for providing multiple waveforms of the defibrillation countershock.

Claim 11

The system of claim 7 in which the non-linear current truncation means includes a uni-junctional field effect transistor having a drain, a source, and a gate in which: the drain is electrically connected to the storage means; the source is electrically connected in series with a resistor to the gate; and the gate is electrically connected to the two or more discharge electrodes.

Claim 12

The system of claim 7 in which the non-linear current truncation means includes a bipolar transistor having a collector, an emitter and a base in which: the collector is electrically connected to the storage means; the emitter is electrically connected in series to the base, the electrical connection commencing from emitter to base comprising a first resistor connected to a series of two or more diodes and the discharge electrodes being electrically connected between the first resistor and the series of two or more diodes; and the base is electrically connected in series to the collector with a second resistor.

Claim 13

The system of claim 7 in which the non-linear current truncation means includes a metal oxide semiconductor field effect transistor having a drain, a source and a gate in which: the drain is electrically connected to the storage means; the source is electrically connected in series to the gate, the electrical connection commencing from source to gate comprising a first resister connected to a Zener diode and the discharge electrodes being electrically connected between the first resistor and the Zener diode; and the gate is electrically connected in series to the drain with a second resistor.

Claim 14

The system of claim 7 in which the non-linear current truncation means includes a metal oxide semiconductor field effect transistor having a drain, a source and a gate in which: the drain is electrically connected to the storage means; the source is electrically connected in series to the gate, the electrical connection commencing from source to gate comprising a first resistor connected to a second resistor connected to a Zener diode and having the discharge electrodes being electrically connected between the first and second resistors; and the gate is electrically connected to the drain, the electrical connection commencing from gate to drain comprising a first connection being a series circuit having a capacitor connected in series with a third resistor and a second connection with a fourth resistor in parallel to the first connection.

Claim 15

The system of claim 6 in which the predetermined amount is less than about 40 Amperes.

Claim 16

The system of claim 6 in which the predetermined amount is less than about 30 Amperes.

Claim 17

The system of claim 6 in which the predetermined amount is less than about 25 Amperes.

Claim 18

The system of claim 6 in which the predetermined amount is less than about 20 Amperes.