System and method of generating an optimal three-step defibrillation waveform for use in an implantable cardioverter/defibrillator (ICD)

A method for making an implantable cardioverter/defibrillator (ICD) comprising:

• determining a system resistance Rs;
• determining a myocardial tissue time constant τm;
• determining capacitances for capacitors of a shocking circuit for use within the ICD by determining C A opt = 0.6673 · ( τ m R s ) ;
• C B opt = 0.6673 · ( τ m R s ) ;
• ⁢ and C C opt = 1.5356 · ( τ m R s ) ;
• determining optimal time periods for three steps of a defibrillation pulse to be generated by the shocking circuit by determining
• d1opt=0.878·τm;
• d2opt=0.277·τm;
• and
• d3opt=0.200·τm;
• fabricating an ICD having a shocking circuit employing capacitors having the determining capacitances;
• and
• configuring the shocking circuit to be capable of selectively discharging the capacitors so as to generate a defibrillation pulse waveform having a first phase with three distinct voltage peaks and having step durations equal to the optimal time periods such that maximum myocardial voltage can be achieved within myocardial tissue connected to the ICD.

A method for making an implantable cardioverter/defibrillator (ICD) comprising:

• selecting capacitances for capacitors of a shocking circuit for use within the ICD;
• determining optimal time periods for three steps of a defibrillation pulse to be generated by the shocking circuit by determining d 1 opt = - τ m α 1 · ln ⁢ { ( τ m τ s1 ) ⁢ ⁢ ( 2 - α 2 α 1 1 - α 2 α 1 ) } ;
• d 2 opt = + τ m α 2 · ln ⁢ { ( 1 2 ) ⁢ ⁢ ( 2 - α 2 α 1 1 - α 2 α 1 ) ⁢ ⁢ ( 1 - α 3 α 2 K C - α 3 α 2 ) } ;
• and d 3 opt = - τ m α 3 · ln ⁢ { ( K C ) ⁢ ⁢ ( 1 - α 3 α 2 K C - α 3 α 2 ) } ;
• wherein
• KC=1+(CC)/(CA+CB+CC);
• α1=1−(τm/τs1), α2=1−(τm/τs2), and α3=1−(τm/τs3);
• τs1=Rs·Cs1;
• τs2=Rs·Cs2;
• and τs3=Rs·Cs3;
• Cs1=CA+CB+CC;
• Cs2=[(CA+CB)·(CC)]/[CA+CB+CC];
• C s3 = 1 ⁢ / ⁢ ⌊ 1 C A + 1 C B + 1 C C ⌋ ;
• CA, CB, & CC are the respective capacitances of the first, second and third capacitors;
• and
• τm is a predetermined myocardial tissue time constant;
• fabricating an ICD having a shocking circuit employing capacitors having the determining capacitances;
• and
• configuring the shocking circuit to be capable of selectively discharging the capacitors so as to generate a defibrillation pulse waveform having step durations equal to the optimal time periods such that maximum myocardial voltage can be achieved within myocardial tissue connected to the ICD.