December 29, 1998                                                       $200,000


                          CARDIAC CONTROL SYSTEMS, INC.
                            12% CONVERTIBLE DEBENTURE
                              DUE DECEMBER 29,2003


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No holder of this  Debenture  shall have any  preemptive  right to  acquire  any
shares or securities of any kind, whether now or hereafter authorized, which may
at any time be Issued, sold or offered for sale by the Company,  except that the
Debenture may be converted into Common Stock as provided herein.

This  Debenture  and the Common Stock of the Company  issuable  upon  conversion
hereof (until such time as such Common Stock is registered  with the  Securities
and Exchange  Commission pursuant to an effective  registration  statement) have
not been registered  under the Securities Act of 1933, as amended,  or any other
securities  statute,  and no sale, transfer or other disposition of any interest
herein may be made  unless,  in the written  opinion of counsel to the  Company,
such transfer would not violate or require  registration under any such statute.
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     1 . Payment.  Cardiac Control  Systems,  Inc., a corporation duly organized
         -------
and existing under the laws of the State of Delaware  (herein referred to as the
"Company'),  for  value  received,  hereby  promises  to pay to  The  Von  Bulow
                                                                 ---------------
Corporation,  or registered assigns ("Holder"), the principal sum of TWO HUNDRED
-----------
THOUSAND DOLLARS,  ($200,000)  together with accrued  interest,  on December 29,
2003 (the  "Maturity  Date"),  in such coin or currency of the United  States of
America  as at the time of  payment  shall be legal  tender  for the  payment of
public and private debts.

     This  Debenture  shall bear simple,  non-cumulative  interest from the date
hereof through the Maturity Date at an interest rate of twelve percent (12%) per
annum;  provided,  however, that whenever the payment of principal is overdue on
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the  Debenture,  interest  shall  accrue,  if  and to the  extent  permitted  by
applicable  law at  fourteen  percent  (14%)  per  annum  on the  entire  unpaid
principal balance of the Debenture so long as any such payment is overdue.

     Interest shall be payable in cash or, at the Company's  discretion,  common
stock  ($.  10  par  value)  of  the  Company  ("Company  Common  Stock"),  or a
combination  thereof,  on each June 30 and December 31 commencing  June 30, 1998
and ending  December  29,  2003,  at which time all  outstanding  principal  and
accrued  and unpaid  interest  shall be due and  payable.  The cash value of any
payments  made in Common Stock of the Company shall be the  Conversion  Price as
hereinafter defined.


     This Debenture is convertible  into Common Stock,  at the option of Holder,
pursuant to Section 2(a) below.

     Upon  conversion  pursuant  to Section 2 below,  the  Company  shall not be
obligated or required to reduce or pay principal outstanding on this Debenture.

<PAGE>

     By  acceptance of this  Debenture,  the Holder agrees that it will promptly
deliver and surrender this  Debenture to the Company upon full payment  thereof,
and that it will promptly notify the Company of any disposition of the Debenture
and of the name and address of the transferee of such Debenture. For purposes of
this  Debenture,  the Company  may assume  that  Holder is the holder  hereunder
unless notified to the contrary in the manner provided in Section 5.

     2. Conversion
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          (a)  Conversion  Right.  In the period  beginning with the date hereof
               -----------------
through the business day  immediately  prior to the Maturity Date (the "Election
Period"),  the  Holder  hereof  shall  have the  right to elect to  convert  the
Debenture  into Common  Stock of the Company as set forth in Section 2(b) below,
in lieu of having the Company repay the  Debenture  pursuant to Section 1 above.
Such  election  shall  be  made in  writing  and  delivered  to the  Company  in
accordance with Section 5.

          (b) Mechanics of Conversion.  At any time,  and, as  applicable,  from
              -----------------------
time to time, the Holder may convert into Common Stock at the  Conversion  Price
the entire  principal  amount  outstanding  on the  Debenture  or the Holder may
convert  incrementally,  and  if  incrementally,  then  the  minimum  amount  so
converted at such time shall be twenty-five  thousand  dollars  ($25,000.00)  of
outstanding  principal.  Upon conversion,  the principal amount of the Debenture
then being  converted shall be converted into Common Stock of the Company on the
Conversion  Date  (defined  below) at the price of one share of Common Stock for
each $0.1875 of outstanding  principal (the "Conversion  Price"). The Conversion
Price and number of shares of Common Stock issuable upon  conversion are subject
to adjustment  as provided this Section 2. No fractional  shares of Common Stock
shall be issued upon  conversion  of the  Debenture.  In lieu of any  fractional
shares to which the Holder would  otherwise be entitled,  the Company  shall pay
cash equal to such fraction  multiplied by the Conversion  Price.  Further,  any
accrued but unpaid interest  outstanding on the Conversion Date shall be paid to
the Holder in cash, or in company Common Stock,  or any  combination  thereof as
provided in Section 1 above. To exercise his conversion rights, the Holder shall
give written  notice to the Company at the Company's  office as indicated  under
Section 5 below,  that he elects to convert the Debenture or portion thereof (in
the minimum  amount of  S25,000.00)  and shall  state  therein the amount of the
outstanding principal that he elects to convert into Common Stock in his name or
the  name or names  of his  nominees  in which  he  wishes  the  certificate  of
certificates for shares of Common Stock to be issued.

          (c)  Issuance of Common  Stock Upon  Conversion.  Within a  reasonable
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time,  not  exceeding  ten (10)  business  days after the  Conversion  Date (the
"Issuance Date'),  the Company shall deliver or cause to be delivered to or upon
the written  order of the Holder of the  Debenture  so  converted,  certificates
representing the number of fully paid and  nonassessable  shares of Common Stock
of the Company into which such Debenture, or increment thereof, may be converted
in accordance  with the provisions of this Section 2. Within a reasonable  time,
not  exceeding  ten (10)  business  days  after  receipt  by the  Holder  of the
certificates.  the Holder of the  Debenture so  converted  shall  surrender  the
Debenture  to the  Company  for  cancellation.  In the  case  of an  incremental
conversion, the Company shall thereupon issue a new Debenture in an amount equal
to the outstanding  principal balance prior to such conversion.  less the amount
of outstanding  principal so converted.  Subject to the following  provisions of
this  Section  2 such  conversion  shall  be  deemed  to  have  occurred  on the
Conversion  Date,  so that the rights of the Holder of such  Debenture  shall be
treated for all purposes as having  become the record  holder or holders of such
shares of Common Stock at such time; provided,  however, that no such conversion
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(when  the  stock  transfer  books  of the  Company  shall be  closed)  shall be
effective to constitute the person or persons  entitled to receive the shares of
Common Stock upon such  conversion on such date,  but such  conversion  shall be
effective to constitute the person or persons entitled to receive such shares of

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<PAGE>

Common Stock as the record  holder or holders  thereof for all purposes at the
close of business on the next  succeeding day on which such stock transfer books
are open. The "Conversion Date" shall be the date the Company receives a. notice
of election from the Holder as provided in Section 2(b).

          (d) Taxes on  Conversion.  The issuance of  certificates  of shares of
              --------------------
Common Stock upon the  conversion of the Debenture  shall be made without charge
by the Company to the  converting  holder for any tax in respect of the issuance
of such  certificates  and such  certificates  shall be issued in the respective
names of, or in such names as may be  directed  by, the Holder of the  Debenture
converted,  provided,  however that the Company shall not be required to pay any
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tax which may be payable in respect of any  transfer  invoked in the issuance or
delivery of any such  certificate in a name other than that of the Holder of the
Debenture  converted,  and the Company shall not be required to issue or deliver
such certificates  unless or until the person or persons requesting the issuance
thereof  shall  have paid to the  Company  the  amount of such tax or shall have
established to the satisfaction of the Company that such tax has been paid.

          (e)  Adjustment  to  Conversion  Price.  At any time after the date on
               ---------------------------------
which the Debenture is first issued. the following adjustments shall apply.

               (i) Stock Dividends,  Distributions or Subdivisions. In the event
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the  Company  shall  issue  additional  shares  of Common  Stock (or  securities
convertible  into  Common  Stock) in a stock  dividend,  stock  distribution  or
subdivision  paid with respect to Common Stock, or declare any dividend or other
distribution  payable  with  additional  shares of Common  Stock (or  securities
convertible into Common Stock) with respect to Common Stock or effect a split or
subdivision  of the  outstanding  shares  of the  Company's  Common  Stock,  the
Conversion  Price  shall  concurrently  with  the  effectiveness  of such  stock
dividend, stock distribution or subdivision, or the earlier declaration thereof,
be proportionately decreased.

               (ii) Combinations or Consolidations. In the event the outstanding
                    ------------------------------
shares of Common Stock shall be combined or consolidated, by reclassification or
otherwise,  into a lesser number of shares of Common Stock, the Conversion Price
shall, concurrently with the effectiveness of such combination or consolidation,
be proportionately increased, and the shares into which this is convertible will
be proportionately decreased.

               (iii) Merger or Reorganization, etc. In case of any consolidation
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or merger of the Company with or into another  corporation  or the conveyance of
all or  substantially  all of the assets of the Company to another  corporation,
each  Debenture  shall  thereafter be  convertible  into the number of shares of
stock or other  securities or property to which a holder of the number of shares
of Common Stock of the Company  deliverable  upon  conversion of such  Debenture
would have been entitled upon such consolidation,  merger or conveyance; and, in
any such case,  appropriate  adjustment  shall be made in the application of the
provisions  herein set forth with respect to the rights and interest  thereafter
of the Holders of  Debentures.  to the end that the  provisions set forth herein
(including  provisions with respect to adjustments in the Conversion  Price with
respect  to  the  Debenture)  shall  thereafter  be  applicable,  as  nearly  as
reasonably  may be,  in  relation  to any  shares  of stock  or  other  property
thereafter deliverable upon the conversion of such Debenture.

          (f) No Impairment.  The Company will not, by amendment of its Articles
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of Incorporation or by-laws or through any  reorganization,  transfer of assets,
consolidation,  merge,  dissolution,  issue or sale of  securities  or any other
voluntary action, avoid or seek to avoid the observance or performance of any of
the terms to be observed or  performed  hereunder by the Company but will at all
times in good faith  assist in the carrying  out of all the  provisions  of this
Section 2 and in

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<PAGE>

the taking of all such action as may be  necessary  or  appropriate  in order to
protect conversion rights of the Holder of this Debenture against impairment.

          (g)  Common  Stock  Reserved.  The  Company  shall  reserve  and  keep
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available out of its authorized but unissued  Common Stock such number of shares
of Common Stock as shall from time to time be sufficient to effect conversion of
the Debenture.

     3. Registration Rights.
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          (a)  Notice of  Registration.  If at any time after the first date set
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forth above, the Company  proposes to file a registration  statement to register
any of its Common Stock under the Securities Act of 1933, as amended (other than
in  connection  with a  merger  or  pursuant  to Form  S-4 or Form  S-8 or other
comparable  form not  available  for  registering  the  shares of  Common  Stock
issuable upon the conversion of this Debenture  (the  '"Registrable  Stock") for
sale to the public),  whether such registration is for the Company's own account
or the account of others, and provided the managing underwriter for the proposed
offering,  if any,  advises the Company that the  inclusion  of the  Registrable
Stock  in such  registration  statement  would  not  jeopardize  the  successful
marketing of the Company Common Stock, in the managing underwriter's exercise of
reasonable  judgment,  then the Company  shall at such time give prompt  written
notice to Holder of its  intention to effect such  registration  setting forth a
description of intended  method of  distribution  and indicating  Holder's right
under such proposed registration,  and upon the request of Holder,  delivered to
the Company  within  twenty (20) days after  giving such notice  (which  request
shall specify the Registrable  Stock intended to be disposed of by Holder),  the
Company shall include such Registrable  Stock held by Holder and requested to be
included in such registration subject to any underwriter's cutback or lock-up.

               (i) Company's  Withdrawal of Registration  Statement.  If, at any
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time after giving such written notice of the Company's intention to register any
of the  Registrable  Stock and prior to the effective  date of the  registration
statement  filed  in  connection  with  such  registration.  the  Company  shall
determine  for any reason not to file the  registration  statement  wherein  the
Registrable Stock would be registered,  to withdraw a registration statement and
abandon the  proposed  offering  in which  Holder had  requested  to include his
Registrable Stock or to delay the registration of such Registrable Stock, at its
sole  election,  the Company may give written  notice of such  determination  to
Holder and  thereupon  shall be  relieved  of its  obligation  to  register  any
Registrable  Stock issued or issuable in connection with such  registration (but
not from its obligation to pay registration  expenses in connection therewith or
to register the Registrable Stock in a subsequent registration); and in the case
of a  determination  to delay a  registration,  the Company  shall  thereupon be
permitted to delay  registering any Registrable Stock for the same period as the
delay in respect of securities being registered for the Company's own account.

               (ii) Holder's  Withdrawal of Registrable  Stock.  Holder shall be
                    ------------------------------------------
permitted to withdraw all or any part of the Registrable Stock at any time prior
to the effective date of such registration.

               (iii)  Holder's  Acceptance of  Underwriting  Terms.  The Company
                      --------------------------------------------
shall  not  be  required  to  include  any  of  the  Registrable  Stock  in  the
registration  statement  relating to an  underwritten  offering of the Company's
securities  unless Holder accepts the terms of the  underwriting  as agreed upon
between the Company and the underwriters  selected by it (provide such terms are
usual and  customary  for selling  stockholders  ) and Holder  agrees to execute
and/or  deliver  such  documents in  connection  with such  registration  as the
Company or the managing underwriter may reasonably request.

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<PAGE>

          (b) Expiration of Registration  Rights. The obligations of the Company
              ----------------------------------
to register shares of the Registrable Stock under this Section 3 shall terminate
ten (10) years after the  Conversion  Date,  unless such  obligations  terminate
earlier in accordance with the terms of this Debenture.

          (c)  Cooperation  with the  Company.  Holder will  cooperate  with the
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Company in all respects.  including,  without  limitation,  timely supplying all
information  reasonably requested by the Company and executing and returning all
documents  reasonably  requested in connection with the registration and sale of
the Registrable Stock.

          (d) Expenses.  All expenses  incurred by the Company in complying with
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the  provisions  of  this  Agreement,   including,   without   limitation,   all
registration and filing fees,  printing expenses,  fees and disbursements of any
counsel and independent  public  accountants for the Company,  fees and expenses
(including  counsel  fees)  incurred in  connection  with  complying  with state
securities or "blue sky" laws,  fees of the National  Association  of Securities
Dealers,  Inc.,  fees of transfer  agents and  registrars and costs of insurance
("Registration Expenses") shall be borne by the Company.  However,  Registration
Expenses shall not include expenses of counsel for Holder, any transfer taxes or
any  underwriting   discounts,   selling   commissions  or  underwriter  expense
reimbursement  allowances  applicable  to  the  sale  of the  Registrable  Stock
("Selling  Expenses").  The  Company  will  pay  all  Registration  Expenses  in
connection  with each  registration  of the  Registrable  Stock  pursuant to the
provisions of this Section 3. All Selling  Expenses in connection with each such
registration statement shall be borne by the participating Holders in proportion
to the number of shares sold by each.

     4.  Events of Default.  If any of the following  events (herein  defined as
         -----------------
"Events Of Default") shall occur and be continuing:  (a) if the Company defaults
in the payment of the  principal  or interest  under this  Debenture or any part
thereof when the same shall  become due and payable,  either by the terms hereof
or otherwise  as herein  provided;  (b) upon the breach of the  covenants of the
Company  contained  in this  Debenture;  (c) if any  proceedings  involving  the
Company  are  commenced  by  or  against  the  Company  under  any   bankruptcy.
reorganization,  arrangement.  insolvency  readjustment of debt,  dissolution or
liquidation  law or statute of the federal  government  or any state  government
and, if such proceedings are instituted against the Company,  the Company by any
action or failure to act indicates its approval of,  consent to or  acquiescence
therein,  or an order shall be entered approving the petition in such proceeding
and, within fifty (50) days after the entry thereof,  such order is not vacated,
or stayed on appeal or otherwise, or shall not otherwise have ceased to continue
in  effect;  then  as to the  Events  of  Default  under  clauses  (a)  and  (b)
hereinabove,  the Holder of this  Debenture  may at its option after thirty (30)
days" advance written notice to the Company (during which time the Company shall
have the right to cure such Event of Default)  declare such Debenture to be and,
all the Debentures  shall thereon become,  forthwith due and payable in cash. If
an Event of  Default  exists  after the  thirty  day notice and a failure of the
Company to cure as provided above, the Holder may pursue all remedies  available
to him at law or  equity.  As to an Event of  Default  under  clause  (c) herein
above,  then the  Debenture  shall be, and all the  Debentures  shall  thereupon
become  immediately  due and  payable  in cash and the  Holder  may  pursue  all
remedies available to him at law or equity.

     5. Communications and Notices.  Except as otherwise  specifically  provided
        --------------------------
herein,  all  communications and notices provided for in this Debenture shall be
sent by express  mail,  facsimile  or  telegram  to the Holder at his address as
provided  to the  Secretary  of the  Company  from time to time  and,  if to the
Company,  at 3 Commerce  Boulevard,  Palm  Coast,  Florida  32037-7961,  for the
attention of the President, or such other address as may be furnished in writing
from time to time.  Any  notice  provided  pursuant  to this  Section 5 shall be
deemed  received upon delivery.  The Company and the holder of any Debenture may
from time to time  change  their  respective  addresses.  for  purposes  of this
Section 5 by

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<PAGE>

written  notice to the other  parties;  provided,  however.  that notice of such
change shall be effective only upon receipt.

     6 Governing Law. This Debenture  shall be construed in accordance  with and
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governed by the laws of the State of Florida.

     7.  Assignment.  This Debenture  shall bind and inure to the benefit of the
         ----------
respective successors and assigns of the parties hereto.

     8. Securities Restrictions.
        -----------------------

     THE  SECLTRITIES  REPRESENTED  HEREBY  HAVE NOT BEEN  REGISTERED  UNDER THE
SECURITIES ACT OF 1933, AS AMENDED,  OR ANY STATE SECURITIES ACTS.  NEITHER SAID
SECURITIES  NOR ANY  SECURITIES  WHICH MAY BE ISSUED IN EXCHANGE  FOR,  UPON THE
CONVERSION OF, OR OTHERWISE IN RESPECT OF, SAID SECURITIES MAY BE SOLD.  OFFERED
FOR SALE, OR ENCUMBERED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT AS
TO SUCH SHARES OR SECURITIES UNDER SAID SECURITIES ACT OF 1933, AS AMENDED,  AND
APPLICABLE STATE  SECURITIES ACTS, OR AN OPINION OF COUNSEL  SATISFACTORY TO THE
COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED.

     9  Waiver.  No  waiver  of a  right  in any  instance  shall  constitute  a
        ------
continuing  waiver  of  successive  rights,  and any one shall  govern  only the
particular matters waived.

     Appropriate  stop  transfers  will be noted  on the  Debentures  and  other
corporate records.

     IN  WITNESS  WHEREOF,  CARDIAC  CONTROL  SYSTEMS,  INC.,  has  caused  this
Debenture  to be  executed  in its  corporate  name by its  President  and Chief
Executive Officer on the date and year first above written.

                                    CARDIAC CONTROL SYSTEMS, INC


                                    BY:  /s/ Alan J. Rabin
                                        -----------------------------
                                            Alan J. Rabin President and Chief
                                            Executive Officer




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