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                                                                   EHXIBIT 10.48



                           RAYTEL MEDICAL CORPORATION

                      AMENDED AND RESTATED PROMISSORY NOTE
                                   $18,000,000

                         Dated as of September 26, 1997

        FOR VALUE RECEIVED, the undersigned, RAYTEL MEDICAL CORPORATION, a
Delaware corporation (hereinafter, together with its successors in title and
assigns, called the "BORROWER"), promises to pay on or before the Final Maturity
Date (as defined in the Credit Agreement to which reference herein is made to
the order of BANQUE PARIBAS (hereinafter, together with its successors in title
and assigns, called the "BANK"), at the Agent's Head Office, the principal sum
of EIGHTEEN MILLION DOLLARS ($18,000,000) in immediately available funds or, if
less, the aggregate unpaid principal amount of the Loans made by the Bank to the
Borrower pursuant to the Credit Agreement to which reference is hereinafter made
and to pay interest, in like money, on the unpaid principal amount owing
hereunder from time to time from the date hereof until payment in full of such
principal amount as provided in the Credit Agreement.

        This Note is made and delivered by the Borrower pursuant to ss.2.4 of
the Amended and Restated Credit Agreement dated as of August 14, 1996 by and
among the Borrower, the Bank and Bank of Boston Connecticut in its capacity as
agent for itself and the lenders therein named (as amended and in effect from
time to time, the "CREDIT AGREEMENT"), and is entitled to the benefits and is
subject to the provisions of the Credit Agreement All capitalized terms used
herein which are defined in the Credit Agreement shall have the same meanings
herein as therein. This Note amends and restates, and is not in satisfaction of,
a certain Promissory Note dated as of September 2, 1996, in the original
principal amount of $10,000,000, previously executed and delivered by the
Borrower to Banque Paribas.

        The Borrower also promises to pay interest on the unpaid principal
amount of the Loans outstanding until paid in full at the rates per annum set
forth in or established pursuant to the Credit Agreement. Such interest shall be
payable on such dates as are determined from time to time pursuant to the Credit
Agreement and shall be calculated as therein provided.

        The Borrower has the right in certain circumstances to prepay the
principal of this Note on the terms and conditions specified in the Credit
Agreement.

        If any Default or Event of Default shall occur, the entire unpaid
principal amount of this Note and all of the unpaid interest accrued thereon may
become or be declared due and payable in the manner and with the effect provided
in the Credit Agreement.

        The Borrower and all guarantors and endorsers hereby waive presentment,
demand, protest and notice of any kind in connection with the delivery,
acceptance, performance and enforcement of this Note, and also hereby assent to
extensions of time of payment or forbearance or other indulgences without
notice.



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        This Note and the obligations of the Borrower hereunder shall be
governed by, and interpreted and determined in accordance with, the laws of the
State of Connecticut.

        THE BORROWER HEREBY REPRESENTS, COVENANTS AND AGREES THAT THE PROCEEDS
OF THE LOANS SHALL BE USED FOR GENERAL COMMERCIAL PURPOSES AND AS FURTHER
PROVIDED IN THE CREDIT AGREEMENT. AND THAT THIS NOTE IS PART OF A "COMMERCIAL
TRANSACTION" AS DEFINED BY THE STATUTES OF THE STATE OF CONNECTICUT. THE
BORROWER HEREBY WAIVES ALL RIGHTS TO NOTICE AND PRIOR COURT HEARING OR COURT
ORDER UNDER CONNECTICUT GENERAL STATUES SECTIONS 52-278A ET SEQ. AS AMENDED OR
UNDER ANY OTHER STATE OR FEDERAL LAW WITH RESPECT TO ANY AND ALL PREJUDGMENT
REMEDIES THE BANK MAY EMPLOY TO ENFORCE ITS RIGHTS AND REMEDIES HEREUNDER. MORE
SPECIFICALLY, THE BORROWER ACKNOWLEDGES THAT BANK'S ATTORNEY MAY, PURSUANT TO
CONNECTICUT GENERAL STATUES, SECTION 52-278F, ISSUE A WRIT FOR A PREJUDGMENT
REMEDY WITHOUT SECURING A COURT ORDER. THE BORROWER ACKNOWLEDGES AND RESERVES
ITS RIGHT TO NOTICE AND A HEARING SUBSEQUENT TO THE ISSUANCE OF A WRIT FOR
PREJUDGMENT REMEDY BY BANK'S ATTORNEY. THE BANK ACKNOWLEDGES THE BORROWER'S
RIGHT TO SAID HEARING SUBSEQUENT TO THE ISSUANCE OF SAID WRIT.

        IN WITNESS WHEREOF, the Borrower has caused this Note to be signed in
its corporate name by its duly authorized officer on the day and in the year
first above written.



                                       RAYTEL MEDICAL CORPORATION



                                       By:  /s/ E. Payson Smith, Jr.
                                          --------------------------------------
                                            Name   E. Payson Smith, Jr.
                                            Title: Chief Financial Officer