<PAGE>

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                FORM 10-Q/A NO. 1

(Mark One)

[x] QUARTERLY REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF
    1934

For the quarterly period ended     SEPTEMBER 30, 2000
                               --------------------------

                                       OR

[ ] TRANSITION REPORT UNDER SECTION 13 OR 15(d) OF THE EXCHANGE ACT


                         Commission file number 0-19567
                                                -------

                              CARDIAC SCIENCE, INC.
                              ---------------------
        (Exact name of Small Business Issuer as specified in its charter)


      DELAWARE                                     33-0465681
-------------------------------------------------------------------------------
   (State or other jurisdiction of              (I.R.S. Employer
    incorporation or organization)              Identification No.)


      16931 MILLIKAN AVENUE, IRVINE, CALIFORNIA              92606
-------------------------------------------------------------------------------
      (Address of principal executive offices)

Registrant's telephone number, including area code:          (949)  587-0357


Check whether the issuer (1) filed all reports required to be filed by Section
13 or 15(d) of the Exchange Act during the past 12 months (or for such shorter
period that the registrant was required to file such reports), and (2) has been
subject to such filing requirements for the past 90 days.

Yes   X         No
    -----          -----

The number of shares of the Common Stock of the registrant outstanding as of
November 8, 2000 was 24,144,764.

<PAGE>

                              CARDIAC SCIENCE, INC.

                 CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS
                                   (Unaudited)
<TABLE>
<CAPTION>
                                                             Three months ended                        Nine months ended

                                                      September 30,       September 30,       September 30,        September 30,
                                                           2000                1999                2000                1999
                                                     -----------------   -----------------   -----------------    ----------------
<S>                                                  <C>                 <C>                 <C>                  <C>
Sales                                                     $ 1,209,682            $    ---         $ 2,759,286            $    ---
Cost of goods sold                                          1,060,102                 ---           2,452,693                 ---
                                                     -----------------   -----------------   -----------------    ----------------
Gross profit                                                  149,580                 ---             306,593                 ---

Operating expenses:
   Research and development                                 3,066,953           1,126,098           5,490,834           2,795,408
   Selling                                                    957,134             252,871           2,783,600             932,792
   General and administrative                               1,554,174             342,917           2,999,315           1,092,542
   Acquired in-process research and development            13,587,026                 ---          13,587,026                 ---
   Amortization of goodwill and other intangibles             567,952                 ---             567,952                 ---
   Amortization of restricted stock                           775,500                 ---             775,500                 ---
                                                     -----------------   -----------------   -----------------    ----------------

Loss from operations                                      (20,359,159)         (1,721,886)        (25,897,634)         (4,820,742)
Interest income (expense), net                                314,718              (2,918)            338,642              (6,550)
                                                     -----------------   -----------------   -----------------    ----------------

Loss from operations before provision for
   income taxes                                           (20,044,441)         (1,724,804)         25,558,992          (4,827,292)
Provision for income taxes                                        ---                 ---               1,600               1,600
                                                     -----------------   -----------------   -----------------    ----------------

Net loss                                                 $(20,044,441)       $ (1,724,804)       $(25,560,592)       $ (4,828,892)
                                                     =================   =================   =================    ================

Net loss per share (basic and diluted)                      $   (0.88)          $   (0.18)           $  (1.47)          $   (0.52)
                                                     =================   =================   =================    ================

Weighted average number of shares used in the
   computation of net loss per share                       22,884,154           9,517,750          17,391,455           9,208,182
                                                     =================   =================   =================    ================
</TABLE>


    The accompanying notes are an integral part of the finanacial statements.


                                                                               4
<PAGE>

RESULTS OF OPERATIONS

         Sales were $1,209,682 and $2,759,286 respectively, for the three and
nine months ended September 30, 2000, as compared to no sales for the three and
nine months ended September 30, 1999. Sales consisted primarily of Powerheart
defibrillator-monitors that were sold to both Medtronic Physio-Control and our
international distributors.

         Cost of sales were $1,060,102 and $2,452,693 respectively, for the
three and nine months ended September 30, 2000, as compared to no cost of sales
for the three and nine months ended September 30, 1999. This amount was
attributable primarily to the sale of Powerhearts.

         Research and development expenses increased to $3,066,953 and
$5,490,834, respectively, for the three and nine months ended September 30,
2000, from $1,126,098 and $2,795,408, respectively, for the three and nine
months ended September 30, 1999. Increases in research and development expenses
included increased expenditures in project costs and engineering personnel
associated with the development of our Automatic Defibrillation Module, Wearable
Cardioverter Defibrillator as well as ongoing support for our Powerheart
product. In addition to these increases we recognized compensation cost of
$551,442 using a Black-Scholes option pricing model for stock options granted to
consultants.

         Selling expenses increased to $957,134 and $2,783,600, respectively,
for the three and nine months ended September 30, 2000, from $252,871 and
$932,792, respectively, for the three and nine months ended September 30, 1999.
The increase was a result of marketing expenditures relating to the sale of the
Powerheart in the United States and international countries. These increase
included personnel and travel costs associated with five regional sales managers
and five clinical application specialists involved in supporting the Medtronic
Physio-Control efforts to market the Powerheart in the United States. Marketing
expense relating to direct mail, trade shows, marketing literature and marketing
studies also increased in the periods.

         General and administrative expenses increased to $1,554,174 and
$2,999,315, respectively, for the three and nine months ended September 30,
2000, from $342,917 and $1,092,542, respectively, for the three and nine
months ended September 30, 1999. The increase in expenses for the quarter and
nine months ended September 30, 2000 as compared to the same periods in 1999
included personnel costs and related fringes, facility costs, consulting,
professional fees and costs associated with the Cadent facility in Bedford,
Massachusetts. In addition to these increases we recognized compensation cost
of $259,810 using a Black-Scholes option pricing model for stock options
granted to consultants.

         For the quarter and nine months ended September 30, 20000 we recorded
certain non-cash charges in connection with our acquisition of Cadent. These
non-cash charges consisted of: acquired in-process research and development of
$13,587,026; amortization of goodwill and other intangibles of $567,952; and
amortization of restricted stock of $775,500.

         Interest income, net, increased to $314,718 and $338,642 for the three
month and year to date periods ended September 30, 2000 as compared to interest
expense net of $2,918 and $6,550, respectively, for the same periods in the
prior year due to the investment of the proceeds from private placements.

         Net loss increased to $20,044,441 or $0.88 per share and $25,560,592
or $1.47 per share, respectively, for the three month and year to date
periods ended September 30, 2000 as compared to $1,724,804 or $0.18 per share
and $4,828,892 or $0.52 per share, respectively, for the three and nine
months ended September 30, 1999. The net loss for the quarter and nine months
ending September 30, 2000 included non-cash charges associated with the
purchase of Cadent, which aggregated $14,785,571 or $0.65 per share and $0.85
per share, respectively.

                                                                              11
<PAGE>

                                   SIGNATURES

         In accordance with the requirements of the Exchange Act, the registrant
caused this report to be signed on its behalf by the undersigned, hereunto duly
authorized.

                                     CARDIAC SCIENCE, INC.
                                     ---------------------

      Date: NOVEMBER 17, 2000        /s/  Brett L. Scott
           -------------------       --------------------------
                                     Brett L. Scott
                                     (Authorized Officer and Principal
                                        Financial Officer)


                                                                              14