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                                                                     EXHIBIT 4.5

                                    GUARANTY

     This GUARANTY (this "Guaranty"), dated as of May 30, 2002, is made and
given by [Name of Subsidiary], a ___________________ (the "Guarantor"), in favor
of each Holder (as such term is defined in the Senior Note and Warrant Purchase
Agreement, dated as of May 29, 2002, by and between Cardiac Science, Inc. (the
"Company") and the purchasers named therein (the "Purchase Agreement")).

     Capitalized terms used herein shall have the meanings assigned to them in
the Purchase Agreement, unless otherwise defined herein.

                              W I T N E S S E T H:

     WHEREAS, pursuant to the Purchase Agreement, the Purchasers have agreed to
purchase the Senior Notes and Warrants;

     WHEREAS, in order to induce the Purchasers to (i) enter into the Purchase
Agreement and the Other Agreements and (ii) purchase the Senior Notes and the
Warrants as provided for in the Purchase Agreement, Guarantor has agreed to
guarantee payment of the Obligations upon the terms, and subject to the
conditions set forth herein;

     NOW, THEREFORE, in consideration of the premises and the covenants
hereinafter contained, and to induce the Purchasers, it is agreed as follows:

1.   DEFINITIONS.

     "Obligations" means the unpaid principal of, and interest and premiums on,
the Senior Notes and all other obligations and liabilities of the Company
(including, without limitation, interest accruing at the then applicable rate
provided in the Purchase Agreement after the maturity of the Senior Notes and
interest accruing at the then applicable rate provided in the Purchase Agreement
after the filing of any petition in bankruptcy, or the commencement of any
insolvency, reorganization or like proceeding, relating to the Company, whether
or not a claim for post-filing or post-petition interest is allowed in such
proceeding) to any Holder, whether direct or indirect, absolute or contingent,
due or to become due, or now existing or hereafter incurred, which may arise
under or out of the Purchase Agreement, this Guaranty and the Other Agreements
entered into by the Company with any Holder or any other document made,
delivered or given in connection therewith, in each case whether on account of
principal, interest, reimbursement obligations, fees, indemnities, costs,
expenses or otherwise (including, without limitation, all reasonable fees and
disbursements of counsel to the Holders that are required to be paid by the
Company pursuant to the terms of any of the foregoing agreements).

     References to this "Guaranty" shall mean this Guaranty, including all
amendments, modifications and supplements and any annexes, exhibits and
schedules to any of the foregoing, and shall refer to this Guaranty as the same
may be in effect at the time such reference becomes operative.

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2.   THE GUARANTY.

     2.1  Guaranty of Obligations. Guarantor hereby unconditionally guarantees
to each Holder, and their respective successors, endorsees, transferees and
assigns, the prompt payment (whether at stated maturity, by acceleration or
otherwise) and performance of the Obligations of the Company (hereinafter the
"Guaranteed Obligations"). Guarantor agrees that this Guaranty is a guaranty of
payment and performance and not of collection, and that its obligations under
this Guaranty shall be primary, absolute and unconditional, irrespective of, and
unaffected by:

         (a) the genuineness, validity, regularity, enforceability or any future
amendment of, or change in this Guaranty, the Purchase Agreement, any of the
Other Agreements or any other agreement, document or instrument to which
Guarantor or the Company is or may become a party;

         (b) the absence of any action to enforce this Guaranty, the Purchase
Agreement or any of the Other Agreements or the waiver or consent by a Holder
with respect to any of the provisions thereof;

         (c) the insolvency of Guarantor or the Company; or

         (d) any other action or circumstances which might otherwise constitute
a legal or equitable discharge or defense of a surety or guarantor;

it being agreed by Guarantor that its obligations under this Guaranty shall not
be discharged until all the Guaranteed Obligations are paid in full. Guarantor
shall be regarded, and shall be in the same position, as principal debtor with
respect to the Guaranteed Obligations. Guarantor agrees that any notice or
directive given at any time to a Holder which is inconsistent with the waiver in
the immediately preceding sentence shall be null and void and may be ignored by
each Holder, and, in addition, may not be pleaded or introduced as evidence in
any litigation relating to this Guaranty for the reason that such pleading or
introduction would be at variance with the written terms of this Guaranty,
unless each of the Holders have specifically agreed otherwise in writing. It is
agreed among Guarantor and the Holders that the foregoing waivers are of the
essence of the transaction contemplated by the Purchase Agreement or Other
Agreements and that, but for this Guaranty and such waivers, the Purchasers
would decline to enter into the Purchase Agreement.

     Anything herein or in the Purchase Agreement or in any Other Agreement to
the contrary notwithstanding, the maximum liability of Guarantor hereunder shall
in no event exceed the amount which can be guaranteed by Guarantor under
applicable federal and state laws relating to the insolvency of debtors.
Guarantor agrees that the Obligations may at any time and from time to time
exceed the amount of the liability of Guarantor hereunder without impairing the
guarantee contained herein or affecting the rights and remedies of any Holder
hereunder.

     2.2  Demand by Holders. In addition to the terms of the Guaranty set forth
in Section 2.1 hereof, and in no manner imposing any limitation on such terms,
it is expressly understood and agreed that, if, at any time, the outstanding
principal amount of the Guaranteed Obligations under the Purchase Agreement
(including all accrued interest thereon) is declared to be immediately due and
payable, then Guarantor shall, without demand, pay to each Holder the entire
outstanding Guaranteed Obligations due and owing to such Holders. Payment by
Guarantor shall be made to the Holders in immediately available funds to an
account, designated by the Holders or at the address set forth


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herein for the giving of notice to the Holders or at any other address that may
be specified in writing from time to time by the Holders, and shall be credited
and applied to the Guaranteed Obligations.

     2.3  Enforcement of Guaranty. In no event shall a Holder have any
obligation (although it is entitled, at its option) to proceed against the
Company or any other Subsidiary thereof before seeking satisfaction from
Guarantor.

     2.4  Waiver. In addition to the waivers contained in Section 2.1 hereof,
Guarantor waives and agrees that it shall not at any time insist upon, plead or
in any manner whatever claim or take the benefit or advantage of, any appraisal,
valuation, stay, extension, marshaling of assets or redemption laws, or
exemption, whether now or at any time hereafter in force, which may delay,
prevent or otherwise affect the performance by Guarantor of its Guaranteed
Obligations under, or the enforcement by the Holders of, this Guaranty.
Guarantor hereby waives diligence, presentment and demand (whether for
non-payment or protest or of acceptance, maturity, extension of time, change in
nature or form of the Guaranteed Obligations, acceptance of further security,
release of further security, composition or agreement arrived at as to the
amount of, or the terms of, the Guaranteed Obligations, notice of adverse change
in the Company's financial condition or any other fact which might increase the
risk to Guarantor) with respect to any of the Guaranteed Obligations or all
other demands whatsoever and waives the benefit of all provisions of law which
are or might be in conflict with the terms of this Guaranty. Guarantor
represents, warrants and agrees that, as of the date of this Guaranty, its
obligations under this Guaranty are not subject to any offsets or defenses
against the Holders, the Company or any Subsidiary thereof of any kind.
Guarantor further agrees that its obligations under this Guaranty shall not be
subject to any counterclaims, offsets or defenses against the Holders, the
Company or any Subsidiary thereof of any kind which may arise in the future.

     2.5  Benefit of Guaranty. The provisions of this Guaranty are for the
benefit of the Holders and their respective successors, transferees, endorsees
and assigns, and nothing herein contained shall impair, as between any Holder,
on the one hand, and the Guarantor or the Company, on the other hand, the
obligations of the Company under the Purchase Agreement or any of the Other
Agreements. In the event all or any part of the Guaranteed Obligations are
transferred, indorsed or assigned by any Holder to any Person or Persons, any
reference to "Holder" herein shall be deemed to refer equally to such Person or
Persons.

     2.6  Modification of Guaranteed Obligations, Etc. Guarantor hereby
acknowledges and agrees that each Holder may at any time or from time to time,
with or without the consent of, or notice to, Guarantor, pursuant to the terms
of such Holder's then existing agreements with the Company:

         (a) change or extend the manner, place or terms of payment of, or renew
or alter all or any portion of, the Guaranteed Obligations;

         (b) take any action under or in respect of the Purchase Agreement or
any of the Other Agreements in the exercise of any remedy, power or privilege
contained therein or available to it at law, equity or otherwise, or waive or
refrain from exercising any such remedies, powers or privileges;

         (c) amend or modify, in any manner whatsoever, the Purchase Agreement
or any of the Other Agreements in accordance with their terms;


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         (d) extend or waive the time for the Guarantor's or the Company's
performance of, or compliance with, any term, covenant or agreement on its part
to be performed or observed under the Purchase Agreement or any of the Other
Agreements, or waive such performance or compliance or consent to a failure of,
or departure from, such performance or compliance;

         (e) release anyone who may be liable in any manner for the payment of
any amounts owed by Guarantor or the Company to any Holder;

         (f) modify or terminate the terms of any intercreditor or subordination
agreement pursuant to which claims of other creditors of the Guarantor or the
Company are subordinated to the claims of the Holders; and/or

         (g) apply any sums by whomever paid or however realized to any amounts
owing by Guarantor or the Company to any Holder in such manner as such Holder
shall determine in its discretion;

and the Holders shall not incur any liability to Guarantor as a result thereof,
and no such action shall impair or release the Guaranteed Obligations of
Guarantor under this Guaranty.

     2.7  Reinstatement. This Guaranty shall remain in full force and effect and
continue to be effective should any petition be filed by or against Guarantor or
the Company for liquidation or reorganization, should Guarantor or the Company
become insolvent or make an assignment for the benefit of creditors or should a
receiver or trustee be appointed for all or any significant part of such
Guarantor's or the Company's assets, and shall continue to be effective or be
reinstated, as the case may be, if at any time payment and performance of the
Guaranteed Obligations, or any part thereof, is, pursuant to applicable law,
rescinded or reduced in amount, or must otherwise be restored or returned by the
Holders, whether as a "voidable preference", "fraudulent conveyance", or
otherwise, all as though such payment or performance had not been made. In the
event that any payment, or any part thereof, is rescinded, reduced, restored or
returned, the Guaranteed Obligations shall be reinstated and deemed reduced only
by such amount paid and not so rescinded, reduced, restored or returned.

     2.8  Deferral of Subrogation, Etc. Notwithstanding anything to the contrary
in this Guaranty, the Purchase Agreement or any of the Other Agreements,
Guarantor hereby:

         (a) expressly and irrevocably waives, on behalf of itself and its
successors and assigns (including any surety) until all Guaranteed Obligations
have been paid in full, any and all rights at law or in equity to subrogation,
to reimbursement, to exoneration, to contribution, to indemnification, to set
off or to any other rights that could accrue to a surety against a principal, to
a guarantor against a principal, to a guarantor against a maker or obligor, to
an accommodation party against the party accommodated, to a holder or transferee
against a maker, or to the holder of any claim against any Person, and which
Guarantor may have or hereafter acquire against the Company in connection with
or as a result of Guarantor's execution, delivery and/or performance of this
Guaranty, or any other documents to which Guarantor is a party or otherwise; and

         (b) acknowledges and agrees (i) that this waiver is intended to benefit
each Holder and shall not limit or otherwise effect Guarantor's liability
hereunder or the enforceability of this Guaranty, and (ii) that each Holder and
their respective successors and assigns are intended third


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party beneficiaries of the waivers and agreements set forth in this Section 2.8
and their rights under this Section 2.8 shall survive payment in full of the
Guaranteed Obligations.

3.   FURTHER ASSURANCES.

     Guarantor hereby agrees, upon the written request of any Holder, to execute
and deliver to such Holder, from time to time, any additional instruments or
documents reasonably considered necessary by such Holder to cause this Guaranty
to be, become or remain valid and effective in accordance with its terms.

4.   OTHER TERMS.

     4.1  Entire Agreement. This Guaranty, together with the Purchase Agreement
and the Other Agreements, constitutes the entire agreement between the parties
with respect to the subject matter hereof and supersedes all prior agreements
relating to a guaranty of the loans and advances under the Purchase Agreement
and the Other Agreements and/or the Guaranteed Obligations.

     4.2  Headings. The headings in this Guaranty are for convenience of
reference only and are not part of the substance of this Guaranty.

     4.3  Severability. Whenever possible, each provision of this Guaranty shall
be interpreted in such a manner to be effective and valid under applicable law,
but if any provision of this Guaranty shall be prohibited by or invalid under
applicable law, such provision shall be ineffective to the extent of such
prohibition or invalidity, without invalidating the remainder of such provision
or the remaining provisions of this Guaranty.

     4.4  Notices. Whenever it is provided herein that any notice, demand,
request, consent, approval, declaration or other communication shall or may be
given to or served upon any of the parties by any other party, or whenever any
of the parties desires to give or serve upon another any such communication with
respect to this Guaranty, each such notice, demand, request, consent, approval,
declaration or other communication shall be in writing and shall be addressed to
the party to be notified as follows:

         (a) If to [Name of Subsidiary], at:

             [                        ]
             [                        ]
             [                        ]
             [                        ]
             Attention:
             Telecopy:

             with copies to:

             Stradling Yocca Carlson & Rauth
             660 Newport Center Drive, Suite 1600
             Newport Beach, CA  92660
             Attention:  Shivbir S. Grewal, Esq.
             Telecopy:  (949) 725-4100


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         (b) If to any Holder, at the address of such Holder specified in the
Purchase Agreement,

or at such other address as may be substituted by notice given as herein
provided. The giving of any notice required hereunder may be waived in writing
by the party entitled to receive such notice. Every notice, demand, request,
consent, approval, declaration or other communication hereunder shall be deemed
to have been validly served, given or delivered (i) upon the earlier of actual
receipt and five (5) Business Days after the same shall have been deposited with
the United States mail, registered or certified mail, return receipt requested,
with proper postage prepaid, (ii) upon transmission, when sent by telecopy or
other similar facsimile transmission (with such telecopy or facsimile promptly
confirmed by delivery of a copy by personal delivery or United States mail as
otherwise provided in this Section 4.4), (iii) one (1) Business Day after
deposit with a reputable overnight carrier with all charges prepaid, or (iv)
when delivered, if hand-delivered by messenger.

     4.5  Successors and Assigns. This Guaranty and all obligations of Guarantor
hereunder shall be binding upon the successors and assigns of Guarantor
(including a debtor-in-possession on behalf of Guarantor) and shall, together
with the rights and remedies of the Holders, hereunder, inure to the benefit of
each Holder, all future holders of any instrument evidencing any of the
Obligations and their respective successors and assigns. Guarantor may not
assign, sell, hypothecate or otherwise transfer any interest in or obligation
under this Guaranty.

     4.6  No Waiver; Cumulative Remedies; Amendments. No Holder shall by any
act, delay, omission or otherwise be deemed to have waived any of its rights or
remedies hereunder, and no waiver shall be valid unless in writing, signed by
all Holders and then only to the extent therein set forth. A waiver by any
Holder of any right or remedy hereunder on any one occasion shall not be
construed as a bar to any right or remedy which the Holders would otherwise have
had on any future occasion. No failure to exercise nor any delay in exercising
on the part of the Holders of any right, power or privilege hereunder, shall
operate as a waiver thereof, nor shall any single or partial exercise of any
right, power or privilege hereunder preclude any other or future exercise
thereof or the exercise of any other right, power or privilege. The rights and
remedies hereunder provided are cumulative and may be exercised singly or
concurrently, and are not exclusive of any rights and remedies provided by law.
None of the terms or provisions of this Guaranty may be waived, altered,
modified, supplemented or amended except by an instrument in writing, duly
executed by the Holders and Guarantor.

     4.7  Termination. This Guaranty is a continuing guaranty and shall remain
in full force and effect until all Guaranteed Obligations have been paid in
full. Upon payment and performance in full of the Guaranteed Obligations, each
Holder shall deliver to Guarantor such documents as Guarantor may reasonably
request to evidence such termination.

     4.8  Counterparts. This Guaranty may be executed in any number of
counterparts, each of which shall collectively and separately constitute one and
the same agreement.

     4.9  Governing Law. This Guaranty shall be governed by and construed in
accordance with the laws of the State of New York applicable to agreements made
and to be performed entirely within such State.


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     IN WITNESS WHEREOF, the parties hereto have executed and delivered this
Guaranty as of the date first above written.

                                          [Name of Subsidiary]

                                          By:
                                             -----------------------------------
                                             Name:
                                             Title:


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