LETTER AMENDMENT NO.6 TO REVOLVING CREDIT AND TERM LOAN AGREEMENT

Exhibit 10.15.6

LETTER AMENDMENT No. 6

Dated as of January 3, 2007

M&I Marshall & Ilsley Bank
651 Nicollet Mall
Minneapolis, Minnesota 55402-1611

Ladies/Gentlemen:

     We refer to the Revolving Credit and Term Loan Agreement dated as of October 17, 2003, as amended (the “Credit Agreement”) between you and us (under our former name of MedAmicus, Inc.). Unless otherwise defined in this letter amendment, terms defined in the Credit Agreement are used in this letter amendment as defined in the Credit Agreement.

     It is hereby agreed by you and us as follows:
The Credit Agreement is, effective the date first above written, hereby amended as follows:

(a)

Section 2.12 is amended by changing the amount of the Term Note B Commitment to be $5,000,000.00 and by changing the Term Note B Termination Date to be March 31, 2007.

     On and after the effective date of this letter