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                                                                 EXHIBIT 10.19.1


                              AMENDMENT NUMBER 1 TO

                            NOTE DATED APRIL 18, 1996


                                                           Sunnyvale, California
                                                                 August 31, 1998


     WHEREAS, on April 18, 1996 Earle Canty (the "Borrower") promised to pay to
Cardiac Pathways Corporation, a Delaware corporation (the "Company"), or order,
the principal sum of Three Hundred and Eight-Five Thousand Dollars ($385,000),
together with interest on the unpaid principal thereof from the date thereof at
the rate of five and eighty-eight one-hundredths percent (5.88%) per annum (the
"April 1996 Note").

     WHEREAS, paragraph 3 of such April 1996 Note provided that:

     "3. Notwithstanding anything to the contrary contained in this Note, the
     entire principal balance and all accrued and unpaid interest thereon shall,
     at the option of the Company, be due and payable upon that date (the
     "Maturity Date") which is the earlier of:

     A.   The date of termination or cessation of employment of the undersigned
     with the Company for any reason, whether voluntary or involuntary, and
     whether with cause or without cause;

     B.   The fifth (5th) anniversary of the date of this Note."

     WHEREAS, the Borrower will cease full-time employment as an officer of the
Company on the date hereof but has agreed to provide consulting services to the
Company for such period of time as is mutually agreeable to the Borrower and the
Company.

1.   NOW, THEREFORE the Company and the Borrower for consideration received
agree to amend the April 1996 Note to amend and restate paragraph 3 in its
entirety as follows:

     "3. Notwithstanding anything to the contrary contained in this Note, the
     entire principal balance and all accrued and unpaid interest thereon shall,
     at the option of the Company, be due and payable upon that date (the
     "Maturity Date") which is the earlier of:

          A.   The date the undersigned ceases or terminates his consulting
     relationship with the Company for any reason, whether voluntary or
     involuntary, and whether with cause or without cause; or

          B.   February 28, 1999."

2.   The remaining terms of the April 1996 Note, the Security Agreement, Joint
Escrow Instructions and Restricted Stock Purchase Agreement related thereto
shall remain in force and effect


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without regard to this Amendment Number 1, and this Amendment Number 1 shall
become a part of the April 1996 Note as if made on and incorporated as of the
date of such note.

3.   This Amendment Number 1 may be executed in counterparts, and both
signatures shall constitute the complete document.

4.   This Amendment Number 1 shall be governed by the laws of the State of
California without regard to conflict of law principles.

     IN WITNESS WHEREOF, this Amendment Number 1 has been entered into as of the
date first set forth above.

EARLE CANTY                            CARDIAC PATHWAYS CORPORATION


/s/ Earle Canty                        By: /s/ William Starling
-------------------------------            ------------------------------  
                                       Its: Chief Executive Officer
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