<PAGE>
                                                                   EXHIBIT 10.58

                 MEDTRONIC SENIOR SUBORDINATED CONVERTIBLE NOTE

THE SECURITIES REPRESENTED HEREBY HAVE BEEN ISSUED WITHOUT REGISTRATION UNDER
THE SECURITIES ACT OF 1933, AS AMENDED, OR UNDER ANY STATE SECURITIES LAWS, AND
MAY NOT BE SOLD, TRANSFERRED OR PLEDGED IN THE ABSENCE OF AN EFFECTIVE
REGISTRATION STATEMENT UNDER APPLICABLE FEDERAL AND STATE SECURITIES LAWS OR AN
OPINION OF COUNSEL SATISFACTORY TO THE BORROWER THAT THE TRANSFER IS EXEMPT FROM
REGISTRATION UNDER APPLICABLE FEDERAL AND STATE SECURITIES LAWS. THIS NOTE IS
SUBJECT TO THE TERMS OF A NOTE PURCHASE AGREEMENT, DATED AS OF MARCH 1, 2002,
BETWEEN THE BORROWER AND THE HOLDER OF THIS NOTE.

                         HORIZON MEDICAL PRODUCTS, INC.

$4,000,000                                                New York, New York

                                                          March 16, 2002

         FOR VALUE RECEIVED, HORIZON MEDICAL PRODUCTS, INC., a Georgia
corporation (the "BORROWER"), promises on the date hereof to pay to the order of
Medtronic, Inc., a Minnesota corporation, the holder hereof, or its order (the
"HOLDER"), on March 16, 2004, the aggregate principal amount of $4,000,000. The
Borrower also promises to pay interest on the unpaid principal amount hereof
from time to time outstanding (the "OUTSTANDING PRINCIPAL AMOUNT"), from the
date hereof until paid in full, at the rates and at the times which shall be
determined in accordance with the provisions of that certain Note Purchase
Agreement, dated as of March 1, 2002 (as amended, restated, supplemented or
otherwise modified from time to time, the "NOTE PURCHASE AGREEMENT"), by and
between the Borrower, the Holder and the other Persons named therein as parties
thereto. This Note shall, at the election of the holder hereof, be convertible
into shares of Company Common Stock of the Borrower, subject to and in
accordance with Section 2.6, 2.7 and 2.8 of the Note Purchase Agreement and
Sections 4 and 5 hereof. Capitalized terms used, but not defined, herein shall
have the meanings assigned to such terms in the Note Purchase Agreement.

         1.       Additional Notes. This Note is one of the Borrower's notes in
the aggregate principal amount of up to $15,000,000 (the "NOTES") and is issued
pursuant to and entitled to the benefits of the Note Purchase Agreement, to
which reference is hereby made for a more complete statement of the terms and
conditions under which these Notes are made and are to be repaid.

         2.       Payments. All payments of principal and interest in respect of
this Note shall be made in lawful money of the United States of America in same
day funds at the principal office of the Holder to which notices are to be given
in accordance with Section 16.6 of the Note Purchase Agreement. Whenever any
payment on this Note shall be stated to be due on a day which is not a Business
Day, such payment shall be made on the next succeeding Business Day and such
extension of time shall be included in the computation of the payment of
interest on this Note.


<PAGE>

         3.       Ranking. This Note and all other Notes shall rank equally
(pari passu) among themselves as to all rights.

         4.       Mechanics of Conversion. Subject to Sections 2.6(b) and 2.7 of
the Note Purchase Agreement, a Holder of the Medtronic Additional Note may
convert it into shares of Company Common Stock at any time during the period
stated in, and as otherwise provided for in Section 2.6(b) or 2.7 of the Note
Purchase Agreement. The conversion of this Note shall be conducted in the
following manner:

                  (a)      Holder's Delivery Requirements. To convert this Note
(in whole or in part) into shares of Company Common Stock on any date, the
Holder shall transmit by facsimile (or otherwise deliver), on or prior to 11:59
p.m., New York City Time, on such date, a copy of either (A) a fully completed
Conversion Period Notice in the event of a conversion pursuant to Section 2.6(b)
or (B) a fully completed Default Conversion Notice in the event of a conversion
pursuant to Section 2.7, in each case executed by the Holder in the form
attached hereto as Exhibit A-1 and Exhibit A-2 (each a "CONVERSION NOTICE") to
the Borrower and shall surrender this Note to a common carrier for delivery to
the Borrower as soon as practicable following such date.

                  (b)      Company's Response. Upon receipt by the Borrower of
copy of a Conversion Notice, the Borrower shall (A) as soon as practicable, but
in any event within one (1) Business Day, send, via facsimile, a confirmation of
receipt of such Conversion Notice to such holder and shall process such
Conversion Notice in accordance with the terms herein and (B) then on or before
the second (2nd) Business Day following the date of receipt by the Borrower of
such Conversion Notice (the "SHARE DELIVERY DATE"), the Borrower shall issue and
deliver to the address as specified in the Conversion Notice, a certificate,
registered in the name of the Holder or its designee, for the number of shares
of Company Common Stock to which the Holder shall be entitled. If the specified
principal amount submitted for conversion is less than the then Outstanding
Principal Amount of this Note, then the Borrower shall, as soon as practicable
and in no event later than three Business Days after receipt of the Note (the
"NOTE DELIVERY DATE") and at its own expense, issue and deliver to the holder a
new Note representing the Outstanding Principal Amount not converted. The
effective date of conversion (the "CONVERSION DATE") shall be deemed to be the
date on which the Borrower receives by facsimile the Conversion Notice, and the
person or persons entitled to receive the shares of Company Common Stock
issuable upon such conversion shall be treated for all purposes as the record
holder or holders of such shares of Company Common Stock on such date. Upon
surrender of a Note that is converted in part, the Borrower shall authenticate
for the holder a new Note equal in principal amount to the unconverted portion
of the Note surrendered. If this Note is converted in part, the remaining
portion of this Note not so converted shall remain entitled to the conversion
rights provided herein. Notwithstanding anything to the contrary expressed or
implied herein or in the Note Purchase Agreement, in the event that a Conversion
Notice is given in accordance herewith on or prior to the date on the 30-day
prepayment notice period referred to Section 3.1(a) of the Note Purchase
Agreement expires, then, in such event, the Borrower shall not be entitled to
prepay this Note and the Holder shall be entitled to convert this Note, in whole
or in part, as stated in such Conversion Notice.

                  (c)      Equity Financing Conversion. In the event of a
conversion of this Note pursuant to Section 2.8 of the Note Purchase Agreement,
(i) this Note shall automatically and without notice or any further action by
any party, convert into that number of shares of equity securities of the
Company as provided for in Section 2.8 of the Note Purchase Agreement, (ii) the
Borrower shall issue and deliver to the address of the Holder as set forth in
the Note Purchase Agreement, a certificate, registered in the name of the Holder
or its designee, for the number of shares of equity securities of the Company to
which the Holder shall be entitled and (iii) the Outstanding Principal Amount
shall automatically and without notice or any further action by any party, be
reduced on the date of such conversion by the dollar amount of the then
Outstanding Principal Amount that is converted at such time.

         5.       Adjustments to Conversion Price.


                                      -2-

<PAGE>

                  (a)      Adjustment of Conversion Price upon Subdivision or
Combination of Company Common Stock. If the Borrower at any time subdivides (by
any stock split, stock dividend, recapitalization or otherwise) its outstanding
shares of Company Common Stock into a greater number of shares, the Conversion
Price in effect immediately prior to such subdivision will be proportionately
reduced. If the Borrower at any time combines (by combination, reverse stock
split or otherwise) its outstanding shares of Company Common Stock into a
smaller number of shares and the Conversion Price in effect immediately prior to
such combination will be proportionately increased.

                  (b)      Notices.

                           (i)      Immediately upon any adjustment of the
Conversion Price pursuant to this Section 5, the Borrower will give written
notice thereof to the Holder, setting forth in reasonable detail, and
certifying, the calculation of such adjustment.

                           (ii)     The Borrower will give written notice to the
Holder at least ten (10) Business Days prior to the date on which the Borrower
closes its books or takes a record (A) with respect to any dividend or
distribution upon the Company Common Stock, (B) with respect to any pro rata
subscription offer to holders of Company Common Stock or (C) for determining
rights to vote with respect to any Organic Change (as hereinafter defined),
dissolution or liquidation, provided that such information shall be made known
to the public prior to or in conjunction with such notice being provided to such
holder.

                           (iii)    The Borrower will also give written notice
to the Holder at least ten (10) Business Days prior to the date on which any
Organic Change, dissolution or liquidation will take place, provided that such
information shall be made known to the public prior to or in conjunction with
such notice being provided to the Holder.

                  (c)      Reorganization, Reclassification, Consolidation,
Merger or Sale. Any recapitalization, reorganization, reclassification,
consolidation, merger, sale of all or substantially all of the Borrower's assets
to another Person or other transaction which is effected in such a way that
holders of Company Common Stock are entitled to receive (either directly or upon
subsequent liquidation) stock, securities or assets with respect to or in
exchange for Company Common Stock is referred to herein as an "ORGANIC CHANGE."
Prior to the consummation of any (i) sale of all or substantially all of the
Borrower's assets to an acquiring Person or (ii) other Organic Change following
which the Borrower is not a surviving entity, the Borrower will secure from the
Person purchasing such assets or the successor, or, if applicable, the parent of
the successor, resulting from such Organic Change (in each case, the "ACQUIRING
ENTITY") a written agreement (in form and substance reasonably satisfactory to
the holders of at least a majority of the Outstanding Principal Amount of the
Notes then outstanding) to deliver to each holder of Notes in exchange for such
shares, a security of the Acquiring Entity evidenced by a written instrument
substantially similar in form and substance to the Notes, including, without
limitation, having a principal amount equal to the Outstanding Principal Amount
and being of rank equal to the Notes held by such holder, and reasonably
satisfactory to the holders of at least a majority of the Outstanding Principal
Amount of the Notes then outstanding. Prior to the consummation of any other
Organic Change, the Borrower shall make appropriate provision (in form and
substance reasonably satisfactory to the holders of at least a majority of the
Outstanding Principal Amount of the Notes then outstanding) to insure that each
of the holders of the Notes will thereafter have the right to acquire and
receive in lieu of or in addition to (as the case may be) the shares of Company
Common Stock immediately theretofore acquirable and receivable upon the
conversion of such holder's Notes such shares of stock, securities or assets
that would have been issued or payable in such Organic Change with respect to or
in exchange for the number of shares of Company Common Stock which would have
been acquirable and receivable upon the conversion of such holder's Notes as of
the date of such Organic Change (without taking into account any limitations or
restrictions on the convertibility of the Notes).


                                      -3-

<PAGE>

         6.       Obligations Absolute. No provision of this Note shall alter or
impair the obligation of the Borrower, which is absolute and unconditional, to
pay the Outstanding Principal Amount of, and interest on, this Note at the time,
place and rate, and in the manner, herein prescribed.

         7.       Waivers of Demand, Etc. The Borrower hereby expressly waives
demand and presentment for payment, notice of nonpayment, protest, notice of
protest, notice of dishonor, notice of acceleration or intent to accelerate,
bringing of suit and diligence in taking any action to collect amounts called
for hereunder and will be directly and primarily liable for the payment of all
sums owing and to be owing hereon, regardless of and without any notice,
diligence, act or omission as or with respect to the collection of any amount
called for hereunder.

         8.       Entire Agreement. This Note, the Note Purchase Agreement and
the Note Documents constitute the full and entire understanding and agreement
between the Borrower and the Holder with respect to the subject hereof. Neither
this Note nor any term hereof may be amended, waived, discharged or terminated
other than by a written instrument signed by the Borrower and the Holder.

         9.       No Waiver. No failure on the part of the Holder to exercise,
and no delay in exercising, any right, remedy or power hereunder shall operate
as a waiver thereof, nor shall any single or partial exercise by the Holder of
any right, remedy or power hereunder preclude any other or future exercise of
any other right, remedy or power. Each and every right, remedy or power hereby
granted to the Holder or allowed it by law or other agreement shall be
cumulative and not exclusive of any other, and may be exercised by the Holder
from time to time.

         10.      Miscellaneous. Unless otherwise provided herein, any notice or
other communication to a party hereunder shall be sufficiently given if in
writing and personally delivered or sent by facsimile with copy sent in another
manner herein provided or sent by courier (which for all purposes of this Note
shall include Federal Express, UPS or other recognized overnight courier) or
mailed to said party by certified mail, return receipt requested, at its address
provided for in the Note Purchase Agreement or such other address as either may
designate for itself in such notice to the other and communications shall be
deemed to have been received when delivered personally, on the scheduled arrival
date when sent by next day or 2-day courier service or if sent by facsimile upon
receipt of transmittal confirmation or if sent by mail then three days after
deposit in the mail. Whenever the sense of this Note requires, words in the
singular shall be deemed to include the plural and words in the plural shall be
deemed to include the singular. If more than one company is named herein, the
liability of each shall be joint and several. Paragraph headings are for
convenience only and shall not affect the meaning of this document.

         11.      Amendments. The terms of this Note are subject to amendment
only in the manner provided in Section 16.1 the Note Purchase Agreement.

         12.      Transfers. This Note is subject to restrictions on transfer or
assignment as provided in Section 16.1 of the Note Purchase Agreement.

         13.      Issue Tax. The issuance of certificates for shares of Company
Common Stock upon conversion of this Note shall be made without charge to the
holder of this Note for any issuance tax in respect thereof.

         14.      Fees/Expenses. The Borrower promises to pay all reasonable
costs and expenses, including reasonable attorneys' fees, all as provided in
Section 16.2 of the Note Purchase Agreement, incurred in the collection and
enforcement of this Note. The Borrower and any endorsers of this Note hereby
consent to renewals and extensions of time at or after the maturity hereof,
without notice, and hereby waive diligence, presentment, protest, demand and
notice of every kind and, to the full extent permitted by law, the right to
plead any statute of limitations as a defense to any demand hereunder.


                                      -4-

<PAGE>

         15.      Governing Law. THIS NOTE SHALL BE GOVERNED BY, AND SHALL BE
CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

         No reference herein to the Note Purchase Agreement and no provision of
this Note or the Note Purchase Agreement shall alter or impair the obligations
of the Borrower, which are absolute and unconditional, to pay the principal of
and interest on this Note at the place, at the respective times, and in the
currency herein prescribed.


                                      -5-

<PAGE>

         IN WITNESS WHEREOF, the Borrower has caused this instrument to be duly
executed by an officer thereunto duly authorized.


                                    Dated:  March 16, 2002


                                    HORIZON MEDICAL PRODUCTS, INC.



                                    By: /s/ William E. Peterson, Jr.
                                       -----------------------------------------
                                       Name:  William E. Peterson, Jr.
                                       Title: President





                                      -6-

<PAGE>

                                   EXHIBIT A-1

                            (To be Executed by Holder
                            in order to Convert Note)

                            CONVERSION PERIOD NOTICE
                                       FOR
                      SENIOR SUBORDINATED CONVERTIBLE NOTE

The undersigned, as Holder of the Medtronic Senior Subordinated Convertible Note
of HORIZON MEDICAL PRODUCTS, INC. (the "Borrower"), in the outstanding principal
amount of $        (the "Note"), hereby elects to convert $        of the
outstanding principal amount of the Note into shares of Company Common Stock,
par value $___ per share (the "Company Common Stock") of the Borrower, according
to the conditions of the Note, as of the date written below. The undersigned
confirms that the representations and warranties contained in Section 4A of the
Note Purchase Agreement entered into in connection with the initial issuance of
the Note are true and correct as to the undersigned as of the date hereof.

         Date of Conversion:
                            ----------------------------------------------------

         Principal Amount of Notes to be converted:
                                                   -----------------------------

         Tax ID Number (If applicable):
                                       -----------------------------------------

Please confirm the following information:

         Conversion Price:
                          ------------------------------------------------------

         Number of shares of Company Common Stock to be issued:
                                                               -----------------

         Please issue the Company Common Stock into which the Notes are being
converted and, if applicable, any check drawn on an account of the Borrower in
the following name and to the following address:

         Issue to:
                  --------------------------------------------------------------

         Address:
                 ---------------------------------------------------------------

         Telephone Number:
                          ------------------------------------------------------

         Facsimile Number:
                          ------------------------------------------------------

         Authorization:
                       ---------------------------------------------------------

         By:
            --------------------------------------------------------------------

         Title:
               -----------------------------------------------------------------

         Dated:

         Account Number (if electronic book entry transfer):
                                                            --------------------

         Transaction Code Number (if electronic book entry transfer):
                                                                     -----------


<PAGE>

                                   EXHIBIT A-2

                            (To be Executed by Holder
                            in order to Convert Note)

                            DEFAULT CONVERSION NOTICE
                                       FOR
                      SENIOR SUBORDINATED CONVERTIBLE NOTE

The undersigned, as Holder of the Medtronic Senior Subordinated Convertible Note
of HORIZON MEDICAL PRODUCTS, INC. (the "Borrower"), in the outstanding principal
amount of $        (the "Note"), hereby elects to convert $        of the
outstanding principal amount of the Note into shares of Company Common Stock,
par value $___ per share (the "Company Common Stock") of the Borrower, according
to the conditions of the Note, as of the date written below. The undersigned
confirms that the representations and warranties contained in Section 4A of the
Note Purchase Agreement entered into in connection with the initial issuance of
the Note are true and correct as to the undersigned as of the date hereof.

         Date of Conversion:
                            ----------------------------------------------------

         Principal Amount of Notes to be converted:
                                                   -----------------------------

         Tax ID Number (If applicable):
                                       -----------------------------------------

Please confirm the following information:

         Conversion Price:
                          ------------------------------------------------------

         Number of shares of Company Common Stock to be issued:
                                                               -----------------


                                      -2-

<PAGE>

         Please issue the Company Common Stock into which the Notes are being
converted and, if applicable, any check drawn on an account of the Borrower in
the following name and to the following address:

Issue to:
         -----------------------------------------------------------------------
Address:
        ------------------------------------------------------------------------
Telephone Number:
                 ---------------------------------------------------------------
Facsimile Number:
                 ---------------------------------------------------------------
Authorization:
              ------------------------------------------------------------------
By:
   -----------------------------------------------------------------------------
Title:
      --------------------------------------------------------------------------
Dated:

Account Number (if electronic book entry transfer):
                                                   -----------------------------
Transaction Code Number (if electronic book entry transfer):
                                                            --------------------


                                      -3-