<PAGE>

                                                                      EXIBIT 4.6
                                                               Execution Version





================================================================================




                          REGISTRATION RIGHTS AGREEMENT


                                  by and among


                              Cardiac Science, Inc.


                                       and


                           The Investors Named Herein






                               -------------------

                               Dated: May 30, 2002

                               -------------------




================================================================================

<PAGE>


                                TABLE OF CONTENTS

                                                                           Page
                                                                           ----

ARTICLE I      DEFINITIONS.................................................. 1

  1.1          Definitions.................................................. 1

ARTICLE II     GENERAL; SECURITIES SUBJECT TO THIS AGREEMENT................ 3

  2.1          Grant of Rights.............................................. 3
  2.2          Registrable Securities....................................... 3
  2.3          Holders of Registrable Securities............................ 3

ARTICLE III    DEMAND REGISTRATION.......................................... 4

  3.1          Request for Demand Registration.............................. 4
  3.2          Incidental or "Piggy-Back" Rights with Respect to a Demand
                 Registration............................................... 4
  3.3          Effective Demand Registration................................ 5
  3.4          Expenses..................................................... 5
  3.5          Underwriting Procedures...................................... 5
  3.6          Selection of Underwriters.................................... 6

ARTICLE IV     INCIDENTAL OR "PIGGY-BACK" REGISTRATION...................... 6

  4.1          Request for Incidental Registration.......................... 6
  4.2          Expenses..................................................... 7

ARTICLE V      FORM S-3 REGISTRATION........................................ 7

  5.1          Request for a Form S-3 Registration.......................... 7
  5.2          Form S-3 Underwriting Procedures............................. 7
  5.3          Limitations on Form S-3 Registrations........................ 8
  5.4          Expenses..................................................... 8
  5.5          No Demand Registration....................................... 8

ARTICLE VI     SHELF REGISTRATION........................................... 8

  6.1          Shelf Registration........................................... 8
  6.2          Effective Shelf Registration................................. 8

ARTICLE VII    REGISTRATION PROCEDURES...................................... 9

  7.1          Obligations of the Company................................... 9
  7.2          Seller Information...........................................12
  7.3          Notice to Discontinue........................................12
  7.4          Registration Expenses........................................12

ARTICLE VIII   INDEMNIFICATION; CONTRIBUTION................................13

  8.1          Indemnification by the Company...............................13
  8.2          Indemnification by Designated Holders........................13
  8.3          Conduct of Indemnification Proceedings.......................14

                                       i

<PAGE>

  8.4          Contribution.................................................15

ARTICLE IX     COVENANTS....................................................15

  9.1          Rule 144.....................................................15
  9.2          Restrictions on Public Sale by the Company...................15

ARTICLE X      MISCELLANEOUS................................................16

  10.1         Recapitalizations, Exchanges, etc............................16
  10.2         No Inconsistent Agreements...................................16
  10.3         Remedies.....................................................16
  10.4         Notices......................................................16
  10.5         Successors and Assigns; Third Party Beneficiaries............18
  10.6         Amendments and Waivers.......................................18
  10.7         Counterparts.................................................18
  10.8         Headings.....................................................18
  10.9         GOVERNING LAW................................................18
  10.10        Severability.................................................18
  10.11        Rules of Construction........................................18
  10.12        Entire Agreement.............................................18
  10.13        Further Assurances...........................................19
  10.14        Other Agreements.............................................19


                                       ii



<PAGE>

                          REGISTRATION RIGHTS AGREEMENT

     REGISTRATION RIGHTS AGREEMENT (this "Agreement"), dated May 30, 2002 (the
                                          ---------
"Effective Date"), by and among Cardiac Science, Inc, a Delaware corporation
 --------------
(the "Company") and the investors whose names are listed on the signature pages
      -------
hereto (the "Investors").
             ---------

     WHEREAS, pursuant to the Senior Note and Warrant Purchase Agreement, dated
May 29, 2002 (the "Purchase Agreement"), by and among the Company and the
                   ------------------
Investors, the Company has agreed to issue and sell to the Investor certain
senior notes and the Warrants (as hereinafter defined); and

     WHEREAS, in order to induce each of the Investors to enter into the
Purchase Agreement and to consummate the transactions contemplated thereby, the
Company has agreed to grant registration rights with respect to the Registrable
Securities (as hereinafter defined) as set forth in this Agreement.

     NOW, THEREFORE, in consideration of the mutual covenants and agreements set
forth herein and for good and valuable consideration, the receipt and adequacy
of which are hereby acknowledged, the parties hereto agree as follows:

                                   ARTICLE I

                                  DEFINITIONS
                                  -----------

     1.1 Definitions. As used in this Agreement, and unless the context requires
         -----------
a different meaning, the following terms have the meanings indicated:

     "Affiliate" shall mean any Person who is an "affiliate" as defined in Rule
      ---------
12b-2 of the General Rules and Regulations under the Exchange Act. In addition,
any partner or member, as the case may be, of an Investor shall be deemed to be
an Affiliate of such Investor.

     "Agreement" means this Agreement as the same may be amended, supplemented
      ---------
or modified in accordance with the terms hereof.

     "Approved Underwriter" has the meaning set forth in Section 3.6.
      --------------------

     "Board of Directors" means the Board of Directors of the Company.
      ------------------

     "Business Day" means any day other than a Saturday, Sunday or other day on
      ------------
which commercial banks in the states of New York or California are authorized or
required by law or executive order to close.

     "Commission" means the Securities and Exchange Commission or any similar
      ----------
agency then having jurisdiction to enforce the Securities Act.

<PAGE>
                                                                               2

     "Common Stock" means the Common Stock, par value $.001 per share, of the
      ------------
Company or any other capital stock of the Company into which such stock is
reclassified or reconstituted.

     "Company" has the meaning set forth in the preamble to this Agreement.
      -------

     "Company Underwriter" has the meaning set forth in Section 4.1.
      -------------------

     "Demand Registration" has the meaning set forth in Section 3.1.
      -------------------

     "Designated Holder" means each of the Investors and any transferee of any
      -----------------
of them to whom the Warrants or Registrable Securities have been transferred in
accordance with Section 10.5 of this Agreement, other than a transferee to whom
Registrable Securities have been transferred pursuant to a Registration
Statement under the Securities Act or Rule 144 or Regulation S promulgated under
the Securities Act (or any successor rule thereto).

     "Effective Date" has the meaning set forth in the preamble to this
      --------------
Agreement.

     "Exchange Act" means the United States Securities Exchange Act of 1934, as
      ------------
amended, and the rules and regulations of the Commission thereunder.

     "Holders' Counsel" has the meaning set forth in Section 7.1(a).
      ----------------

     "Incidental Registration" has the meaning set forth in Section 4.1.
      -----------------------

     "Indemnified Party" has the meaning set forth in Section 8.3.
      -----------------

     "Indemnifying Party" has the meaning set forth in Section 8.3.
      ------------------

     "Initiating Holders" has the meaning set forth in Section 3.1.
      ------------------

     "Inspector" has the meaning set forth in Section 7.1(g).
      ---------

     "Investors" has the meaning set forth in the preamble to this Agreement.
      ---------

     "Liability" has the meaning set forth in Section 8.1.
      ---------

     "NASD" means the National Association of Securities Dealers, Inc.
      ----

     "Person" means any individual, firm, corporation, partnership, trust,
      ------
incorporated or unincorporated association, joint venture, joint stock company,
limited liability company, government (or an agency or political subdivision
thereof) or other entity of any kind, and shall include any successor (by merger
or otherwise) of such entity.

     "Purchase Agreement" has the meaning set forth in the recitals to this
      ------------------
Agreement.

     "Records" has the meaning set forth in Section 7.1(g).
      -------

<PAGE>
                                                                               3

     "Registrable Securities" means each of the following: (a) any and all
      ----------------------
shares of Common Stock issued or issuable upon the exercise of the Warrants, and
(b) any shares of Common Stock issued or issuable to any of the Designated
Holders with respect to the Registrable Securities by way of stock dividend or
stock split or in connection with a combination of shares, recapitalization,
merger, consolidation or other reorganization or otherwise and any shares of
Common Stock issuable upon conversion, exercise or exchange thereof.

     "Registration Expenses" has the meaning set forth in Section 7.4.
      ---------------------

     "Registration Statement" means a Registration Statement filed pursuant to
      ----------------------
the Securities Act.

     "S-3 Initiating Holders" has the meaning set forth in Section 5.1 of this
      ----------------------
Agreement.

     "S-3 Registration" has the meaning set forth in Section 5.1.
      ----------------

     "Securities Act" means the United States Securities Act of 1933, as
      --------------
amended, and the rules and regulations of the Commission promulgated thereunder.

     "Shelf Registration" has the meaning set forth in Section 6.1.
      ------------------

     "Valid Business Reason" has the meaning set forth in Section 3.1.
      ---------------------

     "Warrants" has the meaning set forth in the Purchase Agreement.
      --------

                                   ARTICLE II

                  GENERAL; SECURITIES SUBJECT TO THIS AGREEMENT
                  ---------------------------------------------

     2.1 Grant of Rights. The Company hereby grants registration rights to the
         ---------------
Designated Holders upon the terms and conditions set forth in this Agreement.

     2.2 Registrable Securities. For the purposes of this Agreement, Registrable
         ----------------------
Securities will cease to be Registrable Securities, when (i) a Registration
Statement covering such Registrable Securities has been declared effective under
the Securities Act by the Commission and such Registrable Securities have been
disposed of pursuant to such effective Registration Statement, or (ii) such
Registrable Securities are sold to the public pursuant to Rule 144 under the
Securities Act.

     2.3 Holders of Registrable Securities. A Person is deemed to be a holder of
         ---------------------------------
Registrable Securities whenever such Person owns of record Registrable
Securities, or a security convertible into or exercisable or exchangeable for,
Registrable Securities whether or not such acquisition or conversion has
actually been effected. If the Company receives conflicting instructions,
notices or elections from two or more Persons with respect to the same
Registrable Securities, the Company may act upon the basis of the instructions,
notice or election received from the registered owner of such Registrable
Securities. Registrable Securities issuable upon conversion or exercise of
another security shall be deemed outstanding for the purposes of this Agreement.

<PAGE>
                                                                               4

                                  ARTICLE III

                              DEMAND REGISTRATION
                              -------------------

     3.1 Request for Demand Registration. At any time after the date hereof, in
         -------------------------------
the event that the Company shall become ineligible to register the Registrable
Securities under the Securities Act on Form S-3 (or any successor form thereto),
the Investors holding a majority of the Registrable Securities (the "Initiating
                                                                     ----------
Holders"), may make a written request to the Company to register, and the
-------
Company shall register, under the Securities Act (other than pursuant to a
Registration Statement on Form S-4 or S-8 or any successor thereto) (a "Demand
                                                                        ------
Registration"), the offer and sale of the Registrable Securities stated in such
------------
request; provided, however, that the Company shall not be obligated to effect
         --------  -------
more than two (2) such Demand Registrations for the Investors. For purposes of
the preceding sentence, two or more Registration Statements filed in response to
one demand shall be counted as one Demand Registration. If the Board of
Directors, in its good faith judgment, determines that any registration of
Registrable Securities should not be made or continued because it would
materially interfere with any material financing, acquisition, corporate
reorganization or merger or other material transaction involving the Company (a
"Valid Business Reason"), the Company may (i) postpone filing a Demand
 ---------------------
Registration statement until such Valid Business Reason no longer exists, but in
no event for more than ninety (90) days, and (ii) in the event that a Demand
Registration statement has been filed, if the Valid Business Reason has not
resulted from actions taken by the Company, the Company, upon the approval of a
majority of the Board of Directors, may cause such registration statement to be
withdrawn and its effectiveness terminated or may postpone amending or
supplementing such registration statement. The Company shall give written notice
of its determination to postpone or withdraw a registration statement and of the
fact that the Valid Business Reason for such postponement or withdrawal no
longer exists, in each case, promptly after the occurrence thereof.
Notwithstanding anything to the contrary contained herein, the Company may not
postpone or withdraw a filing under this Section 3.1 more than once in any
twelve (12) month period. Each request for a Demand Registration shall state the
amount of the Registrable Securities proposed to be sold.

     3.2 Incidental or "Piggy-Back" Rights with Respect to a Demand
         ----------------------------------------------------------
Registration. Each of the Designated Holders (other than Initiating Holders who
------------
have requested a registration under Section 3.1) may offer and sell its or his
Registrable Securities under any Demand Registration pursuant to this Section
3.2. Within seven (7) business days after the receipt of a request for a Demand
Registration from an Initiating Holder, the Company shall (i) give written
notice thereof to all of the Designated Holders (other than Initiating Holders
which have requested a registration under Section 3.1), and (ii) subject to
Section 3.5, include in such registration all of the Registrable Securities held
by such Designated Holders from whom the Company has received a written request
for inclusion therein within ten (10) days of the receipt by such Designated
Holders of such written notice referred to in clause (i) above. Each such
request by such Designated Holders shall specify the number of Registrable
Securities to be included in the Registration Statement. The failure of any
Designated Holder to respond within such 10-day period referred to in clause
(ii) above shall be deemed to be a waiver of such Designated Holder's rights
under this Article III with respect to such Demand Registration. Any Designated
Holder may waive its rights under this Article III prior to

<PAGE>
                                                                               5

the expiration of such 10-day period by giving written notice to the Company,
with a copy to the Initiating Holders. If a Designated Holder sends the Company
a written request for inclusion of part or all of such Designated Holder's
Registrable Securities in a registration, such Designated Holder shall not be
entitled to withdraw or revoke such request without the prior written consent of
the Company in its sole discretion unless, as a result of facts or circumstances
relating to the Company or to market conditions arising after the date on which
such request was made, such Designated Holder reasonably determines that
participation in such registration would have a material adverse effect on such
Designated Holder.

     3.3 Effective Demand Registration. The Company shall use its reasonable
         -----------------------------
best efforts to cause any such Demand Registration to become and remain
effective not later than sixty (60) days after the expiration of the ten (10)
day period referred to in clause (ii) in Section 3.2 hereof. A registration
shall not constitute a Demand Registration until it has become effective and
remains continuously effective for the lesser of (i) the period during which all
Registrable Securities registered in the Demand Registration are sold and (ii)
120 days; provided, however, that a registration shall not constitute a Demand
          --------  -------
Registration if (x) after such Demand Registration has become effective, such
registration or the related offer, sale or distribution of Registrable
Securities thereunder is interfered with by any stop order, injunction or other
order or requirement of the Commission or other governmental agency or court for
any reason not attributable to the Initiating Holders and such interference is
not thereafter eliminated or (y) the conditions specified in the underwriting
agreement, if any, entered into in connection with such Demand Registration are
not satisfied or waived, other than by reason of a failure by the Initiating
Holder.

     3.4 Expenses. Subject to Section 7.4 hereof, the Company shall pay all
         --------
Registration Expenses in connection with a Demand Registration, whether or not
such Demand Registration becomes effective.

     3.5 Underwriting Procedures. If the Company or the Initiating Holders
         -----------------------
holding a majority of the Registrable Securities held by all of the Initiating
Holders so elect, the Company shall use its reasonable best efforts to cause
such Demand Registration to be in the form of a firm commitment underwritten
offering and the managing underwriter or underwriters selected for such offering
shall be the Approved Underwriter selected in accordance with Section 3.6. In
connection with any Demand Registration under this Article III involving an
underwritten offering, none of the Registrable Securities held by any Designated
Holder making a request for inclusion of such Registrable Securities pursuant to
Section 3.2 hereof shall be included in such underwritten offering unless such
Designated Holder accepts the terms of the offering as agreed upon by the
Company, the Initiating Holders and the Approved Underwriter, and then only in
such quantity as will not, in the opinion of the Approved Underwriter,
jeopardize the success of such offering by the Initiating Holders. If the
Approved Underwriter advises the Company that the aggregate amount of such
Registrable Securities requested to be included in such offering is sufficiently
large to have a material adverse effect on the success of such offering, then
the Company shall include in such registration only the aggregate amount of
Registrable Securities that the Approved Underwriter believes may be sold
without any such material adverse effect and shall reduce the amount of
Registrable Securities to be included in such registration, first as to

<PAGE>
                                                                               6

the Company, second as to the Designated Holders (who are not Initiating Holders
and who requested to participate in such registration pursuant to Section 3.2
hereof) as a group, if any, and third as to the Initiating Holders as a group,
pro rata within each group based on the number of the Registrable Securities
owned by each such Designated Holder or Initiating Holder, as the case may be.

     3.6 Selection of Underwriters. If any Demand Registration or S-3
         -------------------------
Registration, as the case may be, of Registrable Securities is in the form of an
underwritten offering, the Company shall use its reasonable best efforts to
appoint an investment banking firm of national reputation to act as the managing
underwriter of the offering (the "Approved Underwriter"); provided, however,
                                  --------------------    --------  -------
that the Approved Underwriter shall, in any case, also be approved by the
Initiating Holders or S-3 Initiating Holders holding a majority of Registrable
Securities sought to be registered, as the case may be, such approval not to be
unreasonably withheld.

                                   ARTICLE IV

                     INCIDENTAL OR "PIGGY-BACK" REGISTRATION
                     ---------------------------------------

     4.1 Request for Incidental Registration. At any time after the date hereof,
         -----------------------------------
if the Company proposes to file a Registration Statement under the Securities
Act with respect to an offering by the Company for its own account (other than a
Registration Statement on Form S-4 or S-8 or any successor thereto) or for the
account of any stockholder of the Company other than the Designated Holders,
then the Company shall give written notice of such proposed filing to each of
the Designated Holders at least twenty (20) days before the anticipated filing
date, and such notice shall describe the proposed registration and distribution
and offer such Designated Holders the opportunity to include the number of
Registrable Securities as each such Designated Holder may request (an
"Incidental Registration"). The Company shall use its reasonable best efforts
 -----------------------
(within twenty (20) days of the notice provided for in the preceding sentence)
to cause the managing underwriter or underwriters in the case of a proposed
underwritten offering (the "Company Underwriter") to permit each of the
                            -------------------
Designated Holders who have requested in writing to participate in the
Incidental Registration to include its or his Registrable Securities in such
offering on the same terms and conditions as the securities of the Company or
the account of such other stockholder, as the case may be, included therein. In
connection with any Incidental Registration under this Section 4.1 involving an
underwritten offering, the Company shall not be required to include any
Registrable Securities in such underwritten offering unless the Designated
Holders accept the terms of the underwritten offering as agreed upon between the
Company, such other stockholders, if any, and the Company Underwriter, and then
only in such quantity as the Company Underwriter believes will not jeopardize
the success of the offering by the Company. If the Company Underwriter
determines that the registration of all or part of the Registrable Securities
which the Designated Holders have requested to be included would materially
adversely affect the success of such offering, then the Company shall be
required to include in such Incidental Registration, to the extent of the amount
that the Company Underwriter believes may be sold without causing such material
adverse effect, first, all of the securities to be offered for the account of
the Company; second, the Registrable Securities to be offered for the account of
the Designated Holders pursuant to this Article IV, pro rata based on the number
of Registrable Securities owned by each

<PAGE>
                                                                               7

such Designated Holder; and third, any other securities requested to be included
in such offering.

     4.2 Expenses. Subject to Section 7.4 hereof, the Company shall bear all
         --------
Registration Expenses in connection with any Incidental Registration pursuant to
this Article IV, whether or not such Incidental Registration becomes effective.

                                   ARTICLE V

                             FORM S-3 REGISTRATION
                             ---------------------

     5.1 Request for a Form S-3 Registration. At any time after the date hereof,
         -----------------------------------
if the Shelf Registration Statement is not effective, Designated Holders who
propose to sell their Registrable Securities to the public at an aggregate price
of at least $1,000,000 (the "S-3 Initiating Holders"), shall have the right to
                             ----------------------
make a written request that the Company register, under the Securities Act on
Form S-3 (or any successor form then in effect) (an "S-3 Registration"), all or
                                                     ----------------
a portion of the Registrable Securities owned by such S-3 Initiating Holders.
The Company shall give written notice of such request to all of the Designated
Holders (other than S-3 Initiating Holders which have requested an S-3
Registration under this Section 5.1) at least ten (10) days before the
anticipated filing date of such Form S-3, and such notice shall describe the
proposed registration and offer such Designated Holders the opportunity to
register the number of Registrable Securities as each such Designated Holder may
request in writing to the Company, given within seven (7) days after their
receipt from the Company of the written notice of such registration. With
respect to each S-3 Registration, the Company shall, subject to Section 5.2 (i)
include in such offering the Registrable Securities of the S-3 Initiating
Holders and (ii) use its reasonable best efforts to (x) cause such registration
pursuant to this Section 5.1 to become and remain effective as soon as
practicable and (y) include in such offering the Registrable Securities of the
Designated Holders (other than S-3 Initiating Holders which have requested an
S-3 Registration under this Section 5.1) who have requested in writing to
participate in such registration on the same terms and conditions as the
Registrable Securities of the S-3 Initiating Holders included therein.

     5.2 Form S-3 Underwriting Procedures. If the S-3 Initiating Holders holding
         --------------------------------
a majority of the Registrable Securities held by all of the S-3 Initiating
Holders so elect, the Company shall use its reasonable best efforts to cause
such S-3 Registration pursuant to this Article V to be in the form of a firm
commitment underwritten offering and the managing underwriter or underwriters
selected for such offering shall be the Approved Underwriter selected in
accordance with Section 3.6. In connection with any S-3 Registration under
Section 5.1 involving an underwritten offering, the Company shall not be
required to include any Registrable Securities in such underwritten offering
unless the Designated Holders thereof accept the terms of the underwritten
offering as agreed upon between the Company, the Approved Underwriter and the
S-3 Initiating Holders, and then only in such quantity as such underwriter
believes will not jeopardize the success of such offering by the S-3 Initiating
Holders. If the Approved Underwriter believes that the registration of all or
part of the Registrable Securities which the S-3 Initiating Holders and the
other Designated Holders have requested to be included would materially
adversely affect the success of such public offering, then the Company shall be
required to include in the underwritten offering, to the extent of the amount
that the

<PAGE>

                                                                               8

Approved Underwriter believes may be sold without causing such material adverse
effect, first, all of the Registrable Securities to be offered for the account
of the S-3 Initiating Holders, pro rata based on the number of Registrable
Securities owned by such S-3 Initiating Holders; second, the Registrable
Securities to be offered for the account of the other Designated Holders who
requested inclusion of their Registrable Securities pursuant to Section 5.1, pro
rata based on the number of Registrable Securities owned by such Designated
Holders; and third, any other securities requested to be included in such
offering.

     5.3 Limitations on Form S-3 Registrations. If the Board of Directors has a
         -------------------------------------
Valid Business Reason, the Company may (x) postpone filing a registration
statement relating to a S-3 Registration until such Valid Business Reason no
longer exists, but in no event for more than ninety (90) days, and (y) in case a
registration statement has been filed relating to a S-3 Registration, if the
Valid Business Reason has not resulted from actions taken by the Company, the
Company, upon the approval of a majority of the Board of Directors, may cause
such registration statement to be withdrawn and its effectiveness terminated or
may postpone amending or supplementing such registration statement. The Company
shall give written notice of its determination to postpone or withdraw a
registration statement and of the fact that the Valid Business Reason for such
postponement or withdrawal no longer exists, in each case, promptly after the
occurrence thereof. Notwithstanding anything to the contrary contained herein,
the Company may not postpone or withdraw a filing due to a Valid Business Reason
more than once in any twelve (12) month period.

     5.4 Expenses. Subject to Section 7.4 hereof, the Company shall bear all
         --------
Registration Expenses in connection with any S-3 Registration pursuant to this
Article V and Article VI, whether or not such S-3 Registration becomes
effective.

     5.5 No Demand Registration. No registration requested by any S-3 Initiating
         ----------------------
Holder pursuant to this Article V shall be deemed a Demand Registration pursuant
to Article III.

                                   ARTICLE VI

                               SHELF REGISTRATION
                               ------------------

     6.1 Shelf Registration. Not later than forty-five (45) days after the date
         ------------------
hereof, the Company shall, at its own cost and expense, file with the Commission
a shelf registration statement pursuant to Rule 415 of the Securities Act (the
"Shelf Registration") on Form S-3 (or any successor form thereto), with respect
 ------------------
to the resale, from time to time, of all of the Registrable Securities held by
Designated Holders.

     6.2 Effective Shelf Registration. The Company shall use its reasonable best
         ----------------------------
efforts to cause the Shelf Registration to become effective as soon as
practicable after the date hereof, and shall keep the Shelf Registration
continuously effective under the Securities Act, subject to the provisions of
Section 7.3, until all Registrable Securities registered under the Shelf
Registration are sold.


<PAGE>
                                                                               9

                                  ARTICLE VII

                             REGISTRATION PROCEDURES
                             -----------------------

     7.1 Obligations of the Company. Whenever registration of Registrable
         --------------------------
Securities has been requested pursuant to Article III, Article IV, Article V or
Article VI of this Agreement, the Company shall use its reasonable best efforts
to effect the registration and sale of such Registrable Securities in accordance
with the intended method of distribution thereof as quickly as practicable, and
in connection with any such request, the Company shall, as expeditiously as
possible:

     (a) prepare and file with the Commission a Registration Statement on any
form for which the Company then qualifies or which counsel for the Company shall
deem appropriate and which form shall be available for the sale of such
Registrable Securities in accordance with the intended method of distribution
thereof, and cause such Registration Statement to become effective; provided,
                                                                    --------
however, that (x) before filing a Registration Statement or prospectus or any
-------
amendments or supplements thereto, the Company shall provide counsel selected by
the Designated Holders holding a majority of the Registrable Securities being
registered in such registration ("Holders' Counsel") and any other Inspector
                                  ----------------
with an adequate and appropriate opportunity to review and comment on such
Registration Statement and each prospectus included therein (and each amendment
or supplement thereto) to be filed with the Commission, subject to such
documents being under the Company's control, and (y) the Company shall notify
the Holders' Counsel and each seller of Registrable Securities of any stop order
issued or threatened by the Commission and take all action required to prevent
the entry of such stop order or to remove it if entered;

     (b) prepare and file with the Commission such amendments and supplements to
such Registration Statement and the prospectus used in connection therewith as
may be necessary to keep such Registration Statement effective for the lesser of
(x) 180 days and (y) such shorter period which will terminate when all
Registrable Securities covered by such Registration Statement have been sold;
and shall comply with the provisions of the Securities Act with respect to the
disposition of all securities covered by such Registration Statement during such
period in accordance with the intended methods of disposition by the sellers
thereof set forth in such Registration Statement;

     (c) furnish to each seller of Registrable Securities, prior to filing a
Registration Statement, at least one copy of such Registration Statement as is
proposed to be filed, and thereafter such number of copies of such Registration
Statement, each amendment and supplement thereto (in each case including all
exhibits thereto), and the prospectus included in such Registration Statement
(including each preliminary prospectus) and any prospectus filed under Rule 424
under the Securities Act as each such seller may reasonably request in order to
facilitate the disposition of the Registrable Securities owned by such seller;

     (d) register or qualify the offer and sale of such Registrable Securities
under such other securities or "blue sky" laws of such jurisdictions as any
seller of Registrable Securities may request, and to continue such qualification
in effect in

<PAGE>
                                                                              10

such jurisdiction for as long as permissible pursuant to the laws of such
jurisdiction, or for as long as any such seller requests or until all of such
Registrable Securities are sold, whichever is shortest, and do any and all other
acts and things which may be reasonably necessary or advisable to enable any
such seller to consummate the disposition in such jurisdictions of the
Registrable Securities owned by such seller; provided, however, that the Company
                                             --------  -------
shall not be required to (x) qualify generally to do business in any
jurisdiction where it would not otherwise be required to qualify but for this
Section 7.1(d), (y) subject itself to taxation in any such jurisdiction or (z)
consent to general service of process in any such jurisdiction;

     (e) notify each seller of Registrable Securities at any time when a
prospectus relating thereto is required to be delivered under the Securities
Act, upon discovery that, or upon the happening of any event as a result of
which, the prospectus included in such Registration Statement contains an untrue
statement of a material fact or omits to state any material fact required to be
stated therein or necessary to make the statements therein, in light of the
circumstances under which they were made, not misleading and the Company shall
promptly prepare a supplement or amendment to such prospectus and furnish to
each seller of Registrable Securities a reasonable number of copies of such
supplement to or an amendment of such prospectus as may be necessary so that,
after delivery to the purchasers of such Registrable Securities, such prospectus
shall not contain an untrue statement of a material fact or omit to state any
material fact required to be stated therein or necessary to make the statements
therein, in light of the circumstances under which they were made, not
misleading;

     (f) enter into and perform customary agreements (including an underwriting
agreement in customary form with the Approved Underwriter or Company
Underwriter, if any, selected as provided in Article III, Article IV or Article
V, as the case may be) and take such other actions as are prudent and reasonably
required in order to expedite or facilitate the disposition of such Registrable
Securities, including causing its officers to participate in "road shows" and
other information meetings organized by the Approved Underwriter or Company
Underwriter;

     (g) make available at reasonable times for inspection by any seller of
Registrable Securities, any managing underwriter participating in any
disposition of such Registrable Securities pursuant to a Registration Statement,
Holders' Counsel and any attorney, accountant or other agent retained by any
such seller or any managing underwriter (each, an "Inspector" and collectively,
                                                   ---------
the "Inspectors") (provided that the Designated Holders shall cooperate with
     ----------
each other to minimize, to the extent practicable, the number of such attorneys,
accountants and other agents who are Inspectors so as not to unduly interfere
with the day-to-day operations of the Company and its subsidiaries) all
financial and other records, pertinent corporate documents and properties of the
Company and its subsidiaries (collectively, the "Records") as shall be
                                                 -------
reasonably necessary to enable them to exercise their due diligence
responsibility, and cause the Company's and its subsidiaries' officers,
directors and employees, and the independent public accountants of the Company,
to supply all information reasonably requested by any such Inspector in
connection with such Registration Statement. Records that the Company
determines, in good faith, to be confidential and which it notifies the
Inspectors are confidential shall not be disclosed by the Inspectors (and the
Inspectors shall confirm their agreement in writing in advance to the Company if
the Company shall so request)

<PAGE>
                                                                              11

unless (x) the disclosure of such Records is necessary, in the Company's
judgment, to avoid or correct a misstatement or omission in the Registration
Statement, (y) the release of such Records is ordered pursuant to a subpoena or
other order from a court of competent jurisdiction after exhaustion of all
appeals therefrom or (z) the information in such Records was known to the
Inspectors on a non-confidential basis prior to its disclosure by the Company or
has been made generally available to the public. Each seller of Registrable
Securities agrees that it shall, upon learning that disclosure of such Records
is sought in a court of competent jurisdiction, give notice to the Company and
allow the Company, at the Company's expense, to undertake appropriate action to
prevent disclosure of the Records deemed confidential;

     (h) if such sale is pursuant to an underwritten offering, obtain "cold
comfort" letters dated the effective date of the registration statement and the
date of the closing under the underwriting agreement from the Company's
independent public accountants in customary form and covering such matters of
the type customarily covered by "cold comfort" letters as Holders' Counsel or
the managing underwriter reasonably requests;

     (i) furnish, at the request of any seller of Registrable Securities on the
date such securities are delivered to the underwriters for sale pursuant to such
registration or, if such securities are not being sold through underwriters, on
the date the Registration Statement with respect to such securities becomes
effective, an opinion, dated such date, of counsel representing the Company for
the purposes of such registration, addressed to the underwriters, if any, and to
the seller making such request, covering such legal matters with respect to the
registration in respect of which such opinion is being given as the
underwriters, if any, and such seller may reasonably request and are customarily
included in such opinions;

     (j) comply with all applicable rules and regulations of the Commission, and
make available to its security holders, as soon as reasonably practicable but no
later than fifteen (15) months after the effective date of the Registration
Statement, an earnings statement covering a period of twelve (12) months
beginning after the effective date of the Registration Statement, in a manner
which satisfies the provisions of Section 11(a) of the Securities Act and Rule
158 thereunder;

     (k) cause all such Registrable Securities to be listed on each securities
exchange on which similar securities issued by the Company are then listed,
provided that the applicable listing requirements are satisfied;
--------

     (l) keep Holders' Counsel advised in writing as to the initiation and
progress of any registration under Article III, Article IV, Article V or Article
VI hereunder;

     (m) cooperate with each seller of Registrable Securities and each
underwriter participating in the disposition of such Registrable Securities and
their respective counsel in connection with any filings required to be made with
the NASD; and

     (n) take all other steps reasonably necessary to effect the registration of
the Registrable Securities contemplated hereby.

<PAGE>
                                                                              12

     7.2 Seller Information. The Company may require each seller of Registrable
         ------------------
Securities as to which any registration is being effected to furnish, and such
seller shall furnish, to the Company such information regarding the distribution
of such securities as the Company may from time to time reasonably request in
writing.

     7.3 Notice to Discontinue. Each Designated Holder agrees that, upon receipt
         ---------------------
of any notice from the Company of the happening of any event of the kind
described in Section 7.1(e), such Designated Holder shall forthwith discontinue
disposition of Registrable Securities pursuant to the Registration Statement
covering such Registrable Securities until such Designated Holder's receipt of
the copies of the supplemented or amended prospectus contemplated by Section
7.1(e) and, if so directed by the Company, such Designated Holder shall deliver
to the Company (at the Company's expense) all copies, other than permanent file
copies then in such Designated Holder's possession, of the prospectus covering
such Registrable Securities which is current at the time of receipt of such
notice. If the Company shall give any such notice, the Company shall extend the
period during which such Registration Statement shall be maintained effective
pursuant to this Agreement (including, without limitation, the period referred
to in Section 7.1(b)) by the number of days during the period from and including
the date of the giving of such notice pursuant to Section 7.1(e) to and
including the date when sellers of such Registrable Securities under such
Registration Statement shall have received the copies of the supplemented or
amended prospectus contemplated by and meeting the requirements of Section
7.1(e).

     7.4 Registration Expenses. The Company shall pay all expenses arising from
         ---------------------
or incident to its performance of, or compliance with, this Agreement,
including, without limitation, (i) Commission, stock exchange and NASD
registration and filing fees, (ii) all fees and expenses incurred in complying
with securities or "blue sky" laws (including reasonable fees, charges and
disbursements of counsel to any underwriter incurred in connection with "blue
sky" qualifications of the Registrable Securities as may be set forth in any
underwriting agreement), (iii) all printing, messenger and delivery expenses,
(iv) the fees, charges and disbursements of counsel to the Company and of its
independent public accountants and any other accounting fees, charges and
expenses incurred by the Company (including, without limitation, any expenses
arising from any "cold comfort" letters or any special audits incident to or
required by any registration or qualification), (v) the fees, charges and
expenses of one counsel to the Designated Holders and (vi) any liability
insurance or other premiums for insurance obtained in connection with any Demand
Registration or piggy-back registration thereon, Incidental Registration or S-3
Registration pursuant to the terms of this Agreement, regardless of whether such
Registration Statement is declared effective of the expenses described in the
preceding sentence of this Section 7.4 are referred to herein as "Registration
                                                                  ------------
Expenses." Notwithstanding the foregoing, the fees, charges and expenses of
--------
legal counsel (and other professionals retained by) the Designated Holders
and/or the Approved Underwriter in excess of $350,000 during any twelve-month
period, in the aggregate, shall not be deemed Registration Expenses for all
purposes under this Agreement (and the Company shall be under no obligation to
make any payments in connection therewith); provided, however, that if the
Designated Holders shall cease to own a sufficient number of Registrable
Securities to have the right to designate at least one member to the Company's
Board of Directors pursuant to Section 9.1 of the Purchase Agreement, such fees,
charges and expenses in excess of $175,000 during any twelve-

<PAGE>
                                                                              13

month period, in the aggregate, shall not be deemed Registration Expenses for
all purposes under this Agreement (and the Company shall be under no obligation
to make any payments in connection therewith); and provided, further, that if
the Designated Holders shall cease to own at least 10% of the Registrable
Securities acquired by the Investors on the Effective Date, all such fees and
expenses shall not be deemed Registration Expenses for all purposes under this
Agreement (and the Company shall be under no obligation to make any payments in
connection therewith). In addition, the Designated Holders of Registrable
Securities sold pursuant to a Registration Statement shall bear the expense of
any broker's commission or underwriter's discount or commission relating to
registration and sale of such Designated Holders' Registrable Securities and,
subject to clause (v) above, shall bear the fees and expenses of their own
counsel.

                                  ARTICLE VIII

                         INDEMNIFICATION; CONTRIBUTION
                         -----------------------------

     8.1 Indemnification by the Company. The Company agrees to indemnify and
         ------------------------------
hold harmless each Designated Holder, its partners, directors, officers,
affiliates and each Person who controls (within the meaning of Section 15 of the
Securities Act) such Designated Holder from and against any and all losses,
claims, damages, liabilities and expenses (including reasonable costs of
investigation) (each, a "Liability" and collectively, "Liabilities"), arising
                         ---------                     -----------
out of or based upon any untrue, or allegedly untrue, statement of a material
fact contained in any Registration Statement, prospectus or preliminary
prospectus or notification or offering circular (as amended or supplemented if
the Company shall have furnished any amendments or supplements thereto) or
arising out of or based upon any omission or alleged omission to state therein a
material fact required to be stated therein or necessary to make the statements
therein not misleading under the circumstances such statements were made, except
insofar as such Liability arises out of or is based upon any untrue statement or
alleged untrue statement or omission or alleged omission contained in such
Registration Statement, preliminary prospectus or final prospectus in reliance
and in conformity with information concerning such Designated Holder furnished
in writing to the Company by such Designated Holder expressly for use therein,
including, without limitation, the information furnished to the Company pursuant
to Section 8.2. The Company shall also provide customary indemnities to any
underwriters of the Registrable Securities, their officers, directors and
employees and each Person who controls such underwriters (within the meaning of
Section 15 of the Securities Act) to the same extent as provided above with
respect to the indemnification of the Designated Holders of Registrable
Securities.

     8.2 Indemnification by Designated Holders. In connection with any
         -------------------------------------
Registration Statement in which a Designated Holder is participating pursuant to
Article III, Article IV Article V or Article VI hereof, each such Designated
Holder shall promptly furnish to the Company in writing such information with
respect to such Designated Holder as the Company may reasonably request or as
may be required by law for use in connection with any such Registration
Statement or prospectus and all information required to be disclosed in order to
make the information previously furnished to the Company by such Designated
Holder not materially misleading or necessary to cause such Registration
Statement not to omit a material fact with respect to

<PAGE>
                                                                              14

such Designated Holder necessary in order to make the statements therein not
misleading. Each Designated Holder agrees to indemnify and hold harmless the
Company, any underwriter retained by the Company and each Person who controls
the Company or such underwriter (within the meaning of Section 15 of the
Securities Act) to the same extent as the foregoing indemnity from the Company
to the Designated Holders, but only if such statement or alleged statement or
omission or alleged omission was made in reliance upon and in conformity with
information with respect to such Designated Holder furnished in writing to the
Company by such Designated Holder expressly for use in such registration
statement or prospectus, including, without limitation, the information
furnished to the Company pursuant to this Section 8.2; provided, however, that
                                                       --------  -------
the total amount to be indemnified by such Designated Holder pursuant to this
Section 8.2 shall be limited to the net proceeds received by such Designated
Holder in the offering to which the Registration Statement or prospectus
relates.

     8.3 Conduct of Indemnification Proceedings. Any Person entitled to
         --------------------------------------
indemnification hereunder (the "Indemnified Party") agrees to give prompt
                                -----------------
written notice to the indemnifying party (the "Indemnifying Party") after the
                                               ------------------
receipt by the Indemnified Party of any written notice of the commencement of
any action, suit, proceeding or investigation or threat thereof made in writing
for which the Indemnified Party intends to claim indemnification or contribution
pursuant to this Agreement; provided, however, that the failure so to notify the
                            --------  -------
Indemnifying Party shall not relieve the Indemnifying Party of any Liability
that it may have to the Indemnified Party hereunder (except to the extent that
the Indemnifying Party is materially prejudiced or otherwise forfeits
substantive rights or defenses by reason of such failure). If notice of
commencement of any such action is given to the Indemnifying Party as above
provided, the Indemnifying Party shall be entitled to participate in and, to the
extent it may wish, jointly with any other Indemnifying Party similarly
notified, to assume the defense of such action at its own expense, with counsel
chosen by it and reasonably satisfactory to such Indemnified Party. The
Indemnified Party shall have the right to employ separate counsel in any such
action and participate in the defense thereof, but the fees and expenses of such
counsel shall be paid by the Indemnified Party unless (i) the Indemnifying Party
agrees to pay the same, (ii) the Indemnifying Party fails to assume the defense
of such action with counsel reasonably satisfactory to the Indemnified Party or
(iii) the named parties to any such action (including any impleaded parties)
include both the Indemnifying Party and the Indemnified Party and such parties
have been advised by such counsel that either (x) representation of such
Indemnified Party and the Indemnifying Party by the same counsel would be
inappropriate under applicable standards of professional conduct or (y) there
may be one or more legal defenses available to the Indemnified Party which are
different from or additional to those available to the Indemnifying Party. In
any of such cases, the Indemnifying Party shall not have the right to assume the
defense of such action on behalf of such Indemnified Party, it being understood,
however, that the Indemnifying Party shall not be liable for the fees and
expenses of more than one separate firm of attorneys (in addition to any local
counsel) for all Indemnified Parties. No Indemnifying Party shall be liable for
any settlement entered into without its written consent, which consent shall not
be unreasonably withheld. No Indemnifying Party shall, without the consent of
such Indemnified Party, effect any settlement of any pending or threatened
proceeding in respect of which such Indemnified Party is a party and indemnity
has been sought hereunder by such Indemnified Party, unless such settlement

<PAGE>
                                                                              15

includes an unconditional release of such Indemnified Party from all liability
for claims that are the subject matter of such proceeding.

     8.4 Contribution. If the indemnification provided for in this Article VIII
         ------------
from the Indemnifying Party is unavailable to an Indemnified Party hereunder in
respect of any Liabilities referred to herein, then the Indemnifying Party, in
lieu of indemnifying such Indemnified Party, shall contribute to the amount paid
or payable by such Indemnified Party as a result of such Liabilities in such
proportion as is appropriate to reflect the relative fault of the Indemnifying
Party and Indemnified Party in connection with the actions which resulted in
such Liabilities, as well as any other relevant equitable considerations. The
relative faults of such Indemnifying Party and Indemnified Party shall be
determined by reference to, among other things, whether any action in question,
including any untrue or alleged untrue statement of a material fact or omission
or alleged omission to state a material fact, has been made by, or relates to
information supplied by, such Indemnifying Party or Indemnified Party, and the
parties' relative intent, knowledge, access to information and opportunity to
correct or prevent such action. The amount paid or payable by a party as a
result of the Liabilities referred to above shall be deemed to include, subject
to the limitations set forth in Sections 8.1, 8.2 and 8.3, any legal or other
fees, charges or expenses reasonably incurred by such party in connection with
any investigation or proceeding; provided that the total amount to be
                                 --------
contributed by such Designated Holder shall be limited to the net proceeds
received by such Designated Holder in the offering.

     The parties hereto agree that it would not be just and equitable if
contribution pursuant to this Section 8.4 were determined by pro rata allocation
or by any other method of allocation which does not take account of the
equitable considerations referred to in the immediately preceding paragraph. No
Person guilty of fraudulent misrepresentation (within the meaning of Section
11(f) of the Securities Act) shall be entitled to contribution from any Person
who was not guilty of such fraudulent misrepresentation.

                                   ARTICLE IX

                                   COVENANTS
                                   ---------

     9.1 Rule 144. The Company covenants that from and after the date hereof, it
         --------
shall (a) file any reports required to be filed by it under the Exchange Act and
(b) take such further action as each Designated Holder of Registrable Securities
may reasonably request (including providing any information necessary to comply
with Rule 144 under the Securities Act), all to the extent required from time to
time to enable such Designated Holder to sell Registrable Securities without
registration under the Securities Act within the limitation of the exemptions
provided by (i) Rule 144 under the Securities Act, as such rule may be amended
from time to time, or Regulation S under the Securities Act or (ii) any similar
rules or regulations hereafter adopted by the Commission. The Company shall,
upon the request of any Designated Holder of Registrable Securities, deliver to
such Designated Holder a written statement as to whether it has complied with
such requirements.

<PAGE>
                                                                              16

     9.2 Restrictions on Public Sale by the Company. The Company agrees not to
         ------------------------------------------
effect any public sale or distribution of any of its securities, or any
securities convertible into or exchangeable or exercisable for such securities
(except pursuant to registrations on Form S-4 or S-8 or any successor thereto),
during the period beginning on the effective date of the first Registration
Statement under Article III or Article V in which at least two-thirds of the
Registrable Securities requested to be included in such Registration Statement
were included in such Registration Statement and ending on the earlier of (i)
the date that all Registrable Securities registered on such Registration
Statement are sold and (ii) thirty (30) days after the effective date of such
Registration Statement (except as part of such registration).

                                   ARTICLE X

                                 MISCELLANEOUS
                                 -------------

     10.1 Recapitalizations, Exchanges, etc. The provisions of this Agreement
          ----------------------------------
shall apply to the full extent set forth herein with respect to (i) the shares
of Common Stock, (ii) any and all shares of common stock of the Company into
which the shares of Common Stock are converted, exchanged or substituted in any
recapitalization or other capital reorganization by the Company and (iii) any
and all equity securities of the Company or any successor or assign of the
Company (whether by merger, consolidation, sale of assets or otherwise) which
may be issued in respect of, in conversion of, in exchange for or in
substitution of, the shares of Common Stock and shall be appropriately adjusted
for any stock dividends, splits, reverse splits, combinations, recapitalizations
and the like occurring after the date hereof. The Company shall cause any
successor or assign (whether by merger, consolidation, sale of assets or
otherwise) to enter into a new registration rights agreement with the Designated
Holders on terms substantially the same as this Agreement as a condition of any
such transaction.

     10.2 No Inconsistent Agreements. The Company represents and warrants that,
          --------------------------
except as set forth on Schedule 10.2 hereto, it has not granted to any Person
                       -------------
the right to request or require the Company to register any securities issued by
the Company, other than the rights granted to the Designated Holders herein. The
Company shall not enter into any agreement with respect to its securities that
is inconsistent with the rights granted to the Designated Holders in this
Agreement or grant any additional registration rights to any Person or with
respect to any securities which are not Registrable Securities which are prior
in right to or inconsistent with the rights granted in this Agreement.

     10.3 Remedies. The Designated Holders, in addition to being entitled to
          --------
exercise all rights granted by law, including recovery of damages, shall be
entitled to specific performance of their rights under this Agreement. The
Company agrees that monetary damages would not be adequate compensation for any
loss incurred by reason of a breach by it of the provisions of this Agreement
and hereby agrees to waive in any action for specific performance the defense
that a remedy at law would be adequate.

     10.4 Notices. All notices, demands and other communications provided for or
          -------
permitted hereunder shall be made in writing and shall be made by registered or


<PAGE>
                                                                              17

certified first-class mail, return receipt requested, telecopier, courier
service or personal delivery:

      (a) if to the Company:

          Cardiac Science, Inc.
          16931 Millikan Avenue
          Irvine, California  92606
          Telecopier No.:  949-951-7315
          Attention:  Roderick de Greef

          with a copy to:

          Stradling Yocca Carlson & Rauth
          660 Newport Center Drive, Suite 1600
          Newport Beach, California 92660
          Telecopier No.:  (949) 725-4100
          Attention:  Shivbir S. Grewal, Esq.

      (b) if to any Investor, to such Investor at:

          c/o Perseus, L.L.C.
          888 Seventh Avenue, 29th Floor
          New York, New York  10106
          Telecopier No.:  212-651-6399
          Attention:  Ray E. Newton

          with a copy to:

          Paul, Weiss, Rifkind, Wharton & Garrison
          1285 Avenue of the Americas
          New York, NY 10019-6064
          Telecopy:  (212) 757-3990
          Attention: :  Bruce A. Gutenplan, Esq

     (c)  if to any other Designated Holder, at its address as it appears on the
          record books of the Company.

     All such notices, demands and other communications shall be deemed to have
been duly given when delivered by hand, if personally delivered; when delivered
by courier, if delivered by commercial courier service; five (5) Business Days
after being deposited in the mail, postage prepaid, if mailed; and when receipt
is mechanically acknowledged, if telecopied. Any party may by notice given in
accordance with this Section 10.4 designate another address or Person for
receipt of notices hereunder.

<PAGE>
                                                                              18

     10.5 Successors and Assigns; Third Party Beneficiaries. This Agreement
          -------------------------------------------------
shall inure to the benefit of and be binding upon the successors and permitted
assigns of the parties hereto as hereinafter provided. The rights of the
Designated Holder contained in Articles III, IV, V and VI hereof shall be, with
respect to any Registrable Security that is transferred, automatically
transferred to such transferee. All of the obligations of the Company hereunder
shall survive any such transfer. Except as provided in Article VIII, no Person
other than the parties hereto and their successors and permitted assigns are
intended to be a beneficiary of this Agreement.

     10.6 Amendments and Waivers. Except as otherwise provided herein, the
          ----------------------
provisions of this Agreement may not be amended, modified or supplemented, and
waivers or consents to departures from the provisions hereof may not be given
unless consented to in writing by the Company and Designated Holders that hold
at least 70% of the Registrable Securities; provided that any such amendment,
modification, supplement, waiver or consent to departure that adversely affects
a Designated Holder in a manner differently than it affects the other Designated
Holders shall be effective only with the prior written consent of such
Designated Holder.

     10.7 Counterparts. This Agreement may be executed in any number of
          ------------
counterparts and by the parties hereto in separate counterparts, each of which
when so executed shall be deemed to be an original and all of which taken
together shall constitute one and the same agreement.

     10.8 Headings. The headings in this Agreement are for convenience of
          --------
reference only and shall not limit or otherwise affect the meaning hereof.

     10.9 GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN
          -------------
ACCORDANCE WITH THE LAWS OF THE STATE NEW YORK, WITHOUT REGARD TO THE PRINCIPLES
OF CONFLICTS OF LAW THEREOF.

     10.10 Severability. If any one or more of the provisions contained herein,
           ------------
or the application thereof in any circumstance, is held invalid, illegal or
unenforceable in any respect for any reason, the validity, legality and
enforceability of any such provision in every other respect and of the remaining
provisions hereof shall not be in any way impaired, unless the provisions held
invalid, illegal or unenforceable shall substantially impair the benefits of the
remaining provisions hereof.

     10.11 Rules of Construction. Unless the context otherwise requires,
           ---------------------
references to sections or subsections refer to sections or subsections of this
Agreement.

     10.12 Entire Agreement. This Agreement is intended by the parties as a
           ----------------
final expression of their agreement and intended to be a complete and exclusive
statement of the agreement and understanding of the parties hereto with respect
to the subject matter contained herein. There are no restrictions, promises,
representations, warranties or undertakings with respect to the subject matter
contained herein, other than those set forth or referred to herein. This
Agreement supersedes all prior agreements and understandings among the parties
with respect to such subject matter.

<PAGE>
                                                                              19

     10.13 Further Assurances. Each of the parties shall, and shall cause their
           ------------------
respective Affiliates to, execute such documents and perform such further acts
as may be reasonably required or desirable to carry out or to perform the
provisions of this Agreement.

     10.14 Other Agreements. Nothing contained in this Agreement shall be deemed
           ----------------
to be a waiver of, or release from, any obligations any party hereto may have
under, or any restrictions on the transfer of Registrable Securities or other
securities of the Company imposed by, any other agreement including, but not
limited to, the Warrants.

                  [Remainder of page intentionally left blank]




<PAGE>

     IN WITNESS WHEREOF, the undersigned have executed, or have caused to be
executed, this Registration Rights Agreement on the date first written above.

                             Cardiac Science, Inc.

                             By:_____________________________
                                Name:
                                Title:


                             Investors:
                             ----------

                             Perseus Acquisition/Recapitalization Fund, L.L.C.

                             By _____________________________
                                Name:
                                Title:


                             Perseus Market Opportunity Fund, L.P.

                             By _____________________________
                                Name:
                                Title:


                             Cardiac Science Co-Investment, L.P.

                             By _____________________________
                                Name:
                                Title: