<PAGE>   1
 
      AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MAY 20, 1998
 
                                            REGISTRATION NO. 333-
================================================================================
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            ------------------------
 
                                    FORM S-3
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                            ------------------------
 
                                INCONTROL, INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)
 
<TABLE>
<S>                                              <C>
                    DELAWARE                                        91-1501619
            (STATE OF INCORPORATION)                 (I.R.S. EMPLOYER IDENTIFICATION NUMBER)
</TABLE>
 
                            6675 - 185TH AVENUE N.E.
                           REDMOND, WASHINGTON 98052
                                 (425) 861-9800
   (ADDRESS AND TELEPHONE NUMBER OF REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
 
                                KURT C. WHEELER
                 CHAIRMAN, PRESIDENT & CHIEF EXECUTIVE OFFICER
                                INCONTROL, INC.
                            6675 - 185TH AVENUE N.E.
                           REDMOND, WASHINGTON 98052
                                 (425) 861-9800
           (NAME, ADDRESS AND TELEPHONE NUMBER OF AGENT FOR SERVICE)
 
                                   COPIES TO:
 
                               STEPHEN M. GRAHAM
                                 ALAN C. SMITH
                               PERKINS COIE, LLP
                         1201 THIRD AVENUE, 40TH FLOOR
                         SEATTLE, WASHINGTON 98101-3099
                                 (206) 583-8888
 
        Approximate date of commencement of proposed sale to the public:
     FROM TIME TO TIME AFTER THIS REGISTRATION STATEMENT BECOMES EFFECTIVE.
 
    If the only securities being registered on this form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box.  [ ]
 
    If any of the securities being registered on this form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, as amended, other than securities offered only in connection with dividend
or interest reinvestment plans, check the following box.  [X]
 
    If this form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering.  [ ]
                                                             ---------
 
    If this form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering.  [ ]
                            ---------
 
    If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box.  [ ]
                                     ---------
 
                        CALCULATION OF REGISTRATION FEE
 
<TABLE>
<S>                             <C>                       <C>                  <C>                  <C>
=======================================================================================================================
                                                           PROPOSED MAXIMUM     PROPOSED MAXIMUM
    TITLE OF SECURITIES TO            AMOUNT TO BE          OFFERING PRICE     AGGREGATE OFFERING        AMOUNT OF
        BE REGISTERED                  REGISTERED            PER SHARE(1)           PRICE(1)         REGISTRATION FEE
-----------------------------------------------------------------------------------------------------------------------
Common Stock, $.01 par value
per share(2)..................    4,733,142 shares(3)           $4.219             $19,969,126            $5,891
=======================================================================================================================
</TABLE>
 
(1) Estimated solely for the purpose of calculating the registration fee
    pursuant to Rule 457(c), based on the high and low sales prices of the
    Common Stock on May 18, 1998.
 
(2) Includes associated preferred stock purchase rights. Prior to the occurrence
    of certain events, such rights will not be evidenced or traded separately
    from the Common Stock.
 
(3) Pursuant to Rule 416 under the Securities Act, there are also being
    registered such indeterminate number of additional shares of Common Stock as
    may be issuable upon conversion of the Preferred Stock described herein and
    payment of dividends thereon pursuant to the provisions of the Preferred
    Stock regarding determination of the applicable conversion price and
    dividend rate.
 
    THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF
THE SECURITIES ACT OF 1933 OR UNTIL THIS REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(A),
MAY DETERMINE.
================================================================================
<PAGE>   2
 
INFORMATION CONTAINED HEREIN IS SUBJECT TO COMPLETION OR AMENDMENT. A
REGISTRATION STATEMENT RELATING TO THESE SECURITIES HAS BEEN FILED WITH THE
SECURITIES AND EXCHANGE COMMISSION. THESE SECURITIES MAY NOT BE SOLD NOR MAY
OFFERS TO BUY BE ACCEPTED PRIOR TO THE TIME THE REGISTRATION STATEMENT BECOMES
EFFECTIVE. THIS PROSPECTUS SHALL NOT CONSTITUTE AN OFFER TO SELL OR THE
SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE SECURITIES
IN ANY STATE IN WHICH SUCH OFFER, SOLICITATION OR SALE WOULD BE UNLAWFUL PRIOR
TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS OF ANY SUCH STATE.
 
                    SUBJECT TO COMPLETION DATED MAY 20, 1998
PROSPECTUS
 
                        4,733,142 SHARES OF COMMON STOCK
                                       OF
 
                                INCONTROL, INC.
 
     This Prospectus relates to up to 4,733,142 shares (together with a
presently indeterminate number of additional shares, as described below, the
"Shares") of Common Stock, $.01 par value per share (the "Common Stock"), of
InControl, Inc. (the "Company"). The Shares may be offered by certain
stockholders of the Company (the "Selling Stockholders") from time to time in
transactions in the over-the-counter market through the Nasdaq National Market
("Nasdaq"), or on one or more other securities markets and exchanges, in
privately negotiated transactions, or otherwise, at fixed prices that may be
changed, at market prices prevailing at the time of sale, at prices relating to
such prevailing market prices or at negotiated prices. The Selling Stockholders
may effect such transactions by selling the Shares to or through broker-dealers,
and such broker-dealers may receive compensation in the form of discounts,
concessions or commissions from the Selling Stockholders and/or the purchasers
of the Shares for whom such broker-dealers may act as agents or to whom they may
sell as principals, or both (which compensation as to a particular broker-dealer
may be in excess of customary commissions). See "Selling Stockholders" and "Plan
of Distribution."
 
     None of the proceeds from the sale of the Shares by the Selling
Stockholders will be received by the Company. The Company has agreed to bear all
expenses (other than selling commissions and fees and stock transfer taxes) in
connection with the registration and sale of the Shares being offered by the
Selling Stockholders. The Company has agreed to indemnify the Selling
Stockholders and any broker-dealers who act in connection with the sale of the
Shares hereunder against certain liabilities, including liabilities under the
Securities Act of 1933, as amended (the "Securities Act").
 
     On April 20, 1998, the Company sold 7,500 shares of its Series B
Convertible Preferred Stock, $.01 par value (the "Series B Stock") to the
Selling Stockholders in a private transaction. Pursuant to the terms of the
Certificate of Designations of the Series B Stock regarding payment of
dividends, the Company may, from time to time, issue additional shares of Series
B Stock to the Selling Stockholders in payment of dividends on the Series B
Stock. The Company also entered into a letter agreement (the "Commitment
Letter") dated April 16, 1998, pursuant to which one of the Selling Stockholders
committed to purchase an additional $7.5 million of convertible preferred stock
with terms substantially equivalent to the Series B Stock (together with the
Series B Stock, the "Preferred Stock"). The additional $7.5 million transaction
will be completed at the Company's option, provided certain conditions are met.
 
     The Shares being offered hereby by the Selling Stockholders may be
acquired, from time to time, upon conversion of the Preferred Stock. The Shares
include such presently indeterminate number of additional shares of Common Stock
as may be issued on conversion of the Preferred Stock held by the Selling
Stockholders pursuant to the provisions of the Certificate of Designations of
the Series B Stock and the Certificate of Designations to be filed in connection
with the transaction contemplated by the Commitment Letter regarding
determination of the applicable conversion price. The actual number of shares of
Common Stock issued or issuable upon conversion of the Preferred Stock is
subject to adjustment depending on factors which cannot be predicted by the
Company at this time, including, among others, the future market prices of the
Common Stock, the payment of dividends on the Preferred Stock in additional
shares of Preferred Stock and the completion of the transaction contemplated by
the Commitment Letter.
 
     The Common Stock is quoted on Nasdaq under the symbol "INCL." On May 18,
1998, the closing sales price for the Common Stock as reported on Nasdaq was
$4.4375 per share.
                            ------------------------
 
        THE COMMON STOCK OFFERED HEREBY INVOLVES A HIGH DEGREE OF RISK.
                    SEE "RISK FACTORS" BEGINNING ON PAGE 4.
                            ------------------------
  THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
 EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE SECURITIES
   AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED UPON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
                               CRIMINAL OFFENSE.
                            ------------------------
                THE DATE OF THIS PROSPECTUS IS MAY      , 1998.
<PAGE>   3
 
                             AVAILABLE INFORMATION
 
     The Company is subject to the informational requirements of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), and in accordance
therewith files reports, proxy statements and other information with the
Securities and Exchange Commission (the "Commission"). Such reports, proxy
statements and other information filed by the Company may be inspected and
copied (at prescribed rates) at the public reference facilities maintained by
the Commission in Washington, D.C. (450 Fifth Street, N.W., Judiciary Plaza,
Washington, D.C. 20549) and at the Commission's Regional Offices in New York (7
World Trade Center, 13th Floor, New York, New York 10048) and Chicago (Citicorp
Center, 500 West Madison Street, Suite 1400, Chicago, Illinois 60661). The
Company is an electronic filer and the Commission maintains a web site that
contains reports, proxy and information statements and other information
regarding registrants that file electronically with the Commission. The address
of the web site is "http://www.sec.gov." The Company's reports, proxy statements
and other information may also be inspected at the offices of the National
Association of Securities Dealers, Inc., 1735 K Street, N.W., Washington, D.C.
20006.
 
     This Prospectus is part of a Registration Statement on Form S-3 (together
with all amendments and exhibits thereto, the "Registration Statement") filed
with the Commission under the Securities Act with respect to the Shares offered
hereby. This Prospectus does not contain all the information set forth in the
Registration Statement, certain portions of which have been omitted in
accordance with the Commission's rules and regulations. For further information
with respect to the Company and the Shares offered hereby, reference is made to
the Registration Statement and the exhibits thereto. The statements in this
Prospectus are qualified in their entirety by reference to the contents of any
agreement or other document incorporated herein by reference, a copy of which is
filed as an exhibit to either the Registration Statement or other filings by the
Company with the Commission.
 
                           FORWARD-LOOKING STATEMENTS
 
     This Prospectus includes "forward-looking statements" within the meaning of
the Private Securities Litigation Reform Act of 1995 (the "PSLRA"). The PSLRA
provides a "safe harbor" for such statements to encourage companies to provide
prospective information about themselves so long as such information is
identified as forward-looking and is accompanied by meaningful cautionary
statements identifying important factors that could cause actual results to
differ materially from those projected in the information. All statements other
than statements of historical fact made in this Prospectus or incorporated by
reference are forward-looking. In particular, the statements herein regarding
the availability of adequate funding, progress in the Company's clinical trials,
the granting and timing of regulatory approval for the Company's primary
product, the METRIX System, the status of competitive treatments and products
for the treatment of atrial fibrillation, and the availability and adequacy of
third-party reimbursement for the Company's products are forward-looking
statements. Forward-looking statements represent management's current
expectations and are inherently uncertain. Investors are warned that the
Company's actual results may differ significantly from management's expectations
and, therefore, from the results discussed in such forward-looking statements.
Factors that might cause such differences include, but are not limited to, the
"Risk Factors" described herein.
 
                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
 
     The Company will provide without charge to each person, including any
beneficial owner, to whom a copy of this Prospectus is delivered, upon such
person's written or oral request, a copy of any and all of the documents
incorporated by reference herein (other than exhibits to such documents, unless
such exhibits are specifically incorporated by reference into the information
that this Prospectus incorporates). Requests should be directed to InControl,
Inc., 6675 - 185th Avenue N.E., Redmond, Washington 98052, Attention: Secretary,
telephone: (425) 861-9800.
 
                                        2
<PAGE>   4
 
     The following documents filed with the Commission by the Company are
incorporated by reference into this Prospectus:
 
     (1) The Company's Annual Report on Form 10-K for the year ended December
31, 1997;
 
     (2) The Company's Quarterly Report on Form 10-Q for the quarter ended March
31, 1998;
 
     (3) The Company's Current Report on Form 8-K dated April 20, 1998;
 
     (4) The description of the Common Stock contained in the Company's
         Registration Statement on Form 8-A as of September 8, 1994, including
         any amendment or report filed for the purpose of updating such
         description; and
 
     (5) The description of the Company's rights contained in the Company's
         Registration Statement on Form 8-A filed with the Commission on March
         1, 1996, including any amendment or report filed for the purpose of
         updating such description.
 
     All documents filed with the Commission by the Company pursuant to Section
13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date of this
Prospectus and prior to the termination of the offering of the Shares shall be
deemed to be incorporated by reference into this Prospectus and to be a part
hereof from the respective dates of filing such documents. Any statement
contained in a document incorporated or deemed to be incorporated by reference
herein shall be deemed modified, superseded or replaced for purposes of this
Prospectus to the extent that a statement contained herein or in any
subsequently filed document that also is or is deemed to be incorporated by
reference herein modifies, supersedes or replaces such statement. Any statement
so modified, superseded or replaced shall not be deemed, except as so modified,
superseded or replaced, to constitute a part of this Prospectus.
 
                            ------------------------
 
     The Company's principal executive offices are located at 6675 - 185th
Avenue N.E., Redmond, Washington 98052, telephone: (425) 861-9800.
 
                                        3
<PAGE>   5
 
                                  RISK FACTORS
 
     THIS PROSPECTUS AND THE DOCUMENTS INCORPORATED HEREIN BY REFERENCE CONTAIN
FORWARD-LOOKING STATEMENTS THAT INVOLVE RISKS AND UNCERTAINTIES. THE STATEMENTS
CONTAINED IN THIS PROSPECTUS THAT ARE NOT PURELY HISTORICAL ARE FORWARD-LOOKING
STATEMENTS WITHIN THE MEANING OF SECTION 27A OF THE SECURITIES ACT AND SECTION
21E OF THE EXCHANGE ACT, INCLUDING, WITHOUT LIMITATION, STATEMENTS REGARDING THE
COMPANY'S EXPECTATIONS, BELIEFS, ESTIMATES, INTENTIONS AND STRATEGIES ABOUT THE
FUTURE. WORDS SUCH AS "ANTICIPATES," "EXPECTS," "INTENDS," "PLANS," "BELIEVES,"
"SEEKS," ESTIMATES," VARIATIONS OF SUCH WORDS AND SIMILAR EXPRESSIONS ARE
INTENDED TO IDENTIFY SUCH FORWARD-LOOKING STATEMENTS, BUT THEIR ABSENCE DOES NOT
MEAN THE STATEMENT IS NOT FORWARD-LOOKING. THESE STATEMENTS ARE NOT GUARANTEES
OF FUTURE PERFORMANCE AND ARE SUBJECT TO CERTAIN RISKS, UNCERTAINTIES AND
ASSUMPTIONS THAT ARE DIFFICULT TO PREDICT; THEREFORE, ACTUAL RESULTS MAY DIFFER
MATERIALLY FROM THOSE EXPRESSED OR FORECASTED IN ANY SUCH FORWARD-LOOKING
STATEMENTS AS A RESULT OF CERTAIN FACTORS, INCLUDING THOSE SET FORTH IN THE
FOLLOWING RISK FACTORS, ELSEWHERE IN THIS PROSPECTUS AND IN THE DOCUMENTS
INCORPORATED HEREIN BY REFERENCE. THE COMPANY UNDERTAKES NO OBLIGATION TO UPDATE
PUBLICLY ANY FORWARD-LOOKING STATEMENTS, WHETHER AS A RESULT OF NEW INFORMATION,
FUTURE EVENTS OR OTHERWISE. POTENTIAL INVESTORS SHOULD CONSIDER CAREFULLY THE
FOLLOWING FACTORS, AS WELL AS THE MORE DETAILED INFORMATION CONTAINED ELSEWHERE
IN THIS PROSPECTUS AND IN THE DOCUMENTS INCORPORATED BY REFERENCE, BEFORE MAKING
A DECISION TO INVEST IN THE SHARES OFFERED HEREBY.
 
MARKET ACCEPTANCE; SUBSTANTIAL DEPENDENCE ON SINGLE PRODUCT
 
     Regulatory approval is required in all important markets in which the
Company plans to sell the METRIX System. There can be no assurance, however,
that such approval will be obtained in a timely manner, if at all. Even if
regulatory approval is obtained in each market, there can be no assurance that
the METRIX System will gain market acceptance in any area. Moreover, in Europe,
market acceptance will depend upon the successful completion of various
post-regulatory approval protocols designed to demonstrate the clinical benefits
of the METRIX System, including improvements in patients' quality of life and
the cost-effectiveness of the therapy.
 
     The METRIX System is a new invasive approach to the treatment of atrial
fibrillation ("AF"). Currently, the METRIX System may be marketed only in
Europe, and there are no other implantable devices to treat AF on the market
anywhere in the world. The timing and rate of adoption of new medical technology
cannot be predicted. Substantial clinical experience with the METRIX System will
be required to address patients' and physicians' concerns, including potential
ventricular proarrhythmia, potential shock discomfort and early recurrence of
atrial fibrillation, a condition involving the recurrence of AF within the first
two minutes following a successful cardioversion shock. There can be no
assurance that these concerns will be adequately addressed so as to permit the
successful commercialization of the METRIX System. Since the Company anticipates
that for the foreseeable future it will be substantially dependent on the
successful development and commercialization of the METRIX System and related
future products, failure of the Company to successfully develop and
commercialize the METRIX System and related future products would have a
material adverse effect on the Company's business, financial condition and
results of operations.
 
HISTORY OF LOSSES; FUTURE LOSSES
 
     The design and development of an implantable medical device has required
the Company to make significant investments in research and development
activities since its incorporation in November 1990 and, as such, the Company
has accumulated a deficit of $138.8 million as of March 31, 1998. The Company
 
                                        4
<PAGE>   6
 
expects to incur substantial additional losses in the near future. The Company
expects that revenues from clinical trials and sales of the Company's products
will increase, which increases will moderate future deficit growth. Future
increases in expenses are expected to be primarily due to the Company's
continuing investment in research and development efforts, increases in clinical
trial activities, the maintenance of the European sales organization, the
expansion of domestic marketing and sales capabilities and increasing domestic
manufacturing activity. The amount and timing of the Company's future revenues
and, as a result, the amount and timing of the Company's future losses will be
affected by, among other things, the availability of adequate funding, the
progress and costs of preclinical studies and clinical trials, including the
recruitment of suitable patients, the timing of regulatory approvals, the rate
of market acceptance and adoption of the METRIX System and related future
products, the availability of third-party reimbursement for the Company's
products, the ability to obtain and defend patent and intellectual property
rights and to market the Company's products and the status of competing
products. There can be no assurance that the Company will ever achieve
profitability or generate product revenues sufficient to offset the Company's
losses.
 
NEED FOR SUBSTANTIAL ADDITIONAL CAPITAL
 
     The Company expects its cash needs to continue at their present levels in
future periods due to the Company's planned investment in research and
development, anticipated increases in spending on clinical studies and trial
activities and expansion of marketing, sales and manufacturing capabilities. The
Company's future capital requirements will depend on many factors, including the
progress and costs of preclinical studies and clinical trials, the recruitment
of suitable patients, the timing of regulatory approvals, the rate of market
acceptance and the adoption of the METRIX System and related future products,
the availability of third-party reimbursement for the Company's products, the
ability to obtain and defend patent and intellectual property rights and to
market the Company's products and the status of competing products.
 
     In April 1998, the Company raised $7.5 million through the sale of 7,500
shares of the Preferred Stock in a private transaction. The Company raised an
additional $2.5 million through the sale of 400,000 shares of Common Stock in a
private transaction. In addition, pursuant to the Commitment Letter, one of the
Selling Stockholders has committed to purchase an additional $7.5 million of
convertible preferred stock with terms substantially equivalent to the Series B
Stock. This additional $7.5 million transaction may be completed at the
Company's option if the Company gives such Selling Stockholder notice thereof
during July 1998, provided certain conditions are met.
 
     The Company estimates that, at its planned rate of spending, its existing
cash, cash equivalents, securities available-for-sale, and interest income
thereon, including the $10 million in capital that was raised in April 1998,
will be sufficient to meet its capital requirements into the third quarter of
1998. The additional $7.5 million commitment, if secured, would allow the
Company to continue to fund operations into the fourth quarter of 1998. There
can be no assurance that circumstances in July 1998 will permit the Company to
exercise its option under the Commitment Letter. In addition, there can be no
assurance that the underlying assumed levels of revenue and expense will prove
to be accurate. Whether or not these assumptions prove to be accurate, the
Company will need to raise substantial additional capital in 1998 to fund
operations. The Company intends to seek additional funding through public or
private financing, including equity financing. Adequate funds for these
purposes, whether obtained through financial markets or from other sources, may
not be available when needed or may not be available on terms favorable to the
Company, if at all. If additional funds are raised by issuing equity securities,
dilution to existing shareholders will result. If funding is insufficient at any
time in the future, the Company will be forced to delay, reduce or eliminate
some or all of its research and development activities, clinical studies and
trials and manufacturing and administrative programs, dispose of assets or
technology, or cease operations.
 
DEPENDENCE ON REIMBURSEMENT
 
     Successful sales of the METRIX System in the United States and Europe will
depend on the availability of reimbursement from third-party payors such as
government and private insurance plans. There is significant uncertainty
concerning third-party reimbursement of investigational and newly approved
healthcare products, and there can be no assurance that third-party
reimbursement will be made available for the METRIX
 
                                        5
<PAGE>   7
 
System or that any third-party reimbursement that is obtained will be adequate.
Government and other third-party payors are increasingly scrutinizing patient
indications for medical device therapy and limiting coverage. In Europe,
post-regulatory approval study protocols are required before a device will be
eligible for reimbursement through the various national and local health care
financing authorities. There can be no assurance that these European study
protocols will be completed successfully or that reimbursement will be available
in a timely manner, if at all. If adequate coverage and reimbursement levels are
not provided by government and third-party payors for the METRIX System, the
Company's business and financial condition would be materially adversely
affected.
 
EXTENSIVE GOVERNMENTAL REGULATION AND UNCERTAINTY OF PRODUCT APPROVALS
 
     The Company is subject to significant regulation by authorities in the
United States and Europe regarding the approval of devices and the subsequent
marketing, manufacture and distribution of approved devices.
 
     In the United States, the Company's products have and will continue to
undergo clinical testing followed by an extensive Food and Drug Administration
("FDA") approval process. At the end of the first quarter of 1998, the METRIX
System was in clinical trials in the United States in 25 centers, the number
approved by the FDA. The Company currently has 37 patients enrolled in those
trials, with approval to implant up to a maximum of 170 METRIX atrial
defibrillators. There can be no assurance that the clinical trials will
demonstrate that the METRIX System is safe and effective, or that the Company
will receive FDA approval in a timely manner, if at all. The time required to
complete the U.S. trials is dependent on the rate of patient recruitment, the
performance of the device during the trials and the number of times therapy is
applied to patients enrolled in the study. In addition, delays or rejections may
be encountered based on changes in FDA policy that occur during the development
and approval process. FDA approvals may also be limited, which could limit the
patient population to which the Company's products may be marketed and
distributed. Delays, setbacks or approval limitations related to any of the
factors listed above may have a material adverse effect on the Company's
business and financial condition.
 
     After completing the clinical trials, the Company must submit a Pre-Market
Approval ("PMA") application that is supported by extensive data, including
preclinical and clinical trial data, relating to the safety and effectiveness of
the device. As part of the PMA application process the Company will be required
to submit a full description of its facilities, manufacturing methods and
manufacturing controls. The Company must also fully describe the METRIX System
and the System's components in the PMA application. The Company will then be
required to undergo an initial audit, including a facility inspection, to ensure
that the Company is in compliance with the FDA's Quality System Requirements
regulations (formerly known as Good Manufacturing Practices) and the Medical
Device Reporting regulations and other regulations under the Federal Food, Drug
and Cosmetic Act ("FDC Act") and FDA regulations. There can be no assurance that
the Company will be able to comply with such regulations in a timely fashion,
particularly given the Company's limited manufacturing experience.
 
     Once a PMA application is filed, the FDA may accept it and call for an
advisory panel recommendation or may reject it for insufficient data. Such a
rejection could have significant negative consequences for the Company,
including forcing more costly studies, adversely impacting the market acceptance
of the METRIX System and forcing a possible product recall. After the PMA is
reviewed by the advisory panel, the FDA may approve or reject the product. This
process is lengthy and unpredictable. If the METRIX System PMA application is
approved and the Company markets the METRIX System, the Company will be required
to register with the FDA and to submit device listing information for products
in commercial distribution. The Company and its facilities will then be
periodically re-inspected by the FDA for compliance with the FDC Act and FDA
regulations, including those described above. Labeling and promotional
activities will be subject to scrutiny by the FDA and, in certain circumstances,
by the Federal Trade Commission.
 
     If the FDA determines during the initial audit or during any subsequent
audit that the Company is not in compliance, the FDA has the authority to take
actions that it deems appropriate for any infractions. Such penalties include,
but are not limited to, monetary fines, product recalls, withdrawal of product
approvals, "cease distribution" orders for both domestic and international
products, product seizure and the slowing or
 
                                        6
<PAGE>   8
 
stopping of future product approval processes. In addition, the FDA may
institute civil or criminal legal proceedings against the Company or its
officers. Any such action by the FDA could result in the disruption of the
Company's operations for an indeterminate time, which may have a material
adverse effect on the Company's business and financial condition.
 
     In Europe, the Company has received the needed certifications required in
order to declare compliance with the European Active Implantable Device
Directive ("AIMDD") and affix the conformite europeenne ("CE") mark to the
METRIX System components. While the CE mark allows the Company to distribute and
market the METRIX System throughout the European Community ("EC"), the Company
will need to complete studies regarding the cost benefits of the therapy before
it will be eligible to receive reimbursement approvals from the medical
reimbursing authorities in various EC member countries. There can be no
assurance that such approvals from the reimbursing authorities will be obtained
in a timely manner, if at all. Failure to obtain such approvals could
significantly delay or prevent the adoption of the METRIX System in Europe and
thereby have a material adverse effect on the Company's business and financial
condition.
 
     As part of the CE mark approval process the Company was required to obtain
certifications of its quality system under the AIMDD from TUV Product Services
of Munich, Germany (the "Notified Body"), an organization accredited to provide
such quality system certification. The Notified Body will perform periodic
audits to ascertain whether the Company has maintained its quality system and is
in compliance with the certification requirements under the AIMDD. If
certification is revoked, the Company may be prevented from distributing its
product in the EC. In addition, if an individual EC country's regulatory
authority deems the METRIX System to be "unsafe" for any reason, the Company may
find it impossible to distribute its product throughout the EC. A
de-certification of the Company's quality system or an "unsafe" determination by
any regulatory authority would have a material adverse effect on the Company's
business and financial condition.
 
SIGNIFICANT COMPETITION
 
     The METRIX System is a new technology that must compete with the
established treatments for AF: pharmaceuticals, external electrical
cardioversion, atrioventricular node ablation accompanied by pacemaker
implantation and open-heart surgical ablation. Furthermore, although currently
no implantable device is being marketed to treat AF (with the exception of the
METRIX atrial defibrillator in Europe), certain manufacturers of implantable
ventricular defibrillators and pacemakers are developing dual-chamber
defibrillator systems that will be used to treat patients with both ventricular
and atrial arrhythmias and may be marketed to patients who have only AF. One
such dual chamber defibrillator system has started clinical trials in Europe.
Some of the Company's competitors are also researching other approaches to the
treatment of AF, including endocardial ablation and preventative pacing
techniques. In addition, other companies and research organizations, academic
institutions and governmental agencies may be pursuing alternative approaches
for the treatment of AF. These entities may market products to treat AF either
on their own or through collaborative efforts. Many of the Company's competitors
have substantially greater financial and other resources, larger research and
development staffs and more experience and capabilities in conducting research
and development activities, testing products in clinical trials, obtaining
regulatory approvals and manufacturing, marketing and distributing products than
the Company. The Company's competitors may develop new technologies and products
that are available for sale prior to the METRIX System or that are more
effective than the METRIX System. In addition, competitive products may be
manufactured and marketed more successfully than the METRIX System. Such
developments could render the METRIX System less competitive or obsolete and
could have a material adverse effect on the Company's business and financial
condition. In addition, the Company intends for its future products to include
bradycardia pacing technology. Any such products are likely to face direct
competition from more established medical device companies with financial and
other resources significantly greater than those of the Company.
 
DEPENDENCE ON SOLE SOURCES OF SUPPLY
 
     The Company relies on outside vendors to manufacture certain major
components used in the METRIX System. A number of significant components, such
as hybrid circuits, batteries, integrated circuits, capacitors and transformers,
are supplied by sole source vendors. For certain of these components, there are
relatively few
 
                                        7
<PAGE>   9
 
alternative sources of supply, and establishing additional or replacement
suppliers for such components, particularly hybrid circuits and batteries,
cannot be accomplished quickly. In addition, each supplier and each component
must be qualified with the FDA, and the time required for such qualification may
be lengthy. The establishment of additional or replacement sources of supply
would require the Company to certify the new suppliers, which, in the case of
certain components, would cause a delay in the Company's ability to manufacture
its products. The Company's inability to obtain acceptable components in a
timely manner or find and maintain suitable replacement suppliers would have a
material adverse effect on the Company's ability to manufacture the METRIX
System and therefore on its business and financial condition.
 
INDUSTRY HISTORY OF PATENT LITIGATION; DEPENDENCE ON PATENTS AND PROPRIETARY
RIGHTS
 
     The segment of the medical device industry that includes implantable
defibrillator systems has been characterized by extensive litigation regarding
patents and other intellectual property rights. Litigation may be necessary to
enforce patents issued to the Company, to protect trade secrets or know-how
owned by the Company or to determine the enforceability, scope and validity of
proprietary rights of others. Such litigation may result in substantial expense
to the Company and significant diversion of effort by the Company's technical
and management personnel. An adverse determination in any such litigation could
subject the Company to significant liability to third parties or require the
Company to seek licenses from third parties. Although patent and intellectual
property disputes in the medical device industry have often been settled through
licensing or similar arrangements, costs associated with such arrangements may
be substantial and could include ongoing royalties. Moreover, there can be no
assurance that necessary licenses would be available to the Company on
satisfactory terms, if at all. If such licenses could not be obtained on
acceptable terms, the Company could be prevented from marketing certain devices
in the METRIX System family or future related products. Accordingly, an adverse
determination in such litigation could have a material adverse effect on the
Company's business and financial condition. The Company's success will depend in
part on its ability to obtain and maintain patent protection for its
technologies. There can be no assurance that issued patents or pending
applications will not be challenged or circumvented by competitors, or that the
rights granted thereunder will provide competitive advantages to the Company.
 
LIMITED MANUFACTURING AND MARKETING EXPERIENCE
 
     The METRIX System has never been manufactured on a commercial scale and
there can be no assurance that it can be manufactured at a cost or in quantities
necessary to make it commercially viable. There can be no assurance that the
Company's reliance on others for the manufacture of its components will not
result in problems with product supply. Interruptions in the availability of
components would delay or prevent the development and commercialization of the
METRIX System. The Company expects to expand its domestic manufacturing capacity
and its European and domestic marketing and sales capabilities. There can be no
assurance that the Company will be able to recruit and retain skilled sales,
marketing and manufacturing management, direct salespersons or distributors, or
that the Company's expansion efforts will be successful. In markets where the
Company has entered or enters into distribution arrangements for the sale of the
METRIX System, the Company will depend on the efforts of third parties. There
can be no assurance that such efforts will be successful.
 
DEPENDENCE ON KEY PERSONNEL
 
     The Company is highly dependent on certain members of its scientific and
professional staff, the loss of whose services might impede the achievement of
its research and development or strategic objectives. Competition among medical
device companies for highly skilled and uniquely experienced scientific and
professional personnel is intense. The Company's currently limited financial
resources may compromise its ability to compete effectively for such skilled
personnel. The Company's anticipated growth and expansion in areas and
activities requiring additional expertise, such as marketing and sales, clinical
trials and manufacturing, are expected to place significant increased demands on
the Company's resources. These demands are expected to require the addition of
new professional personnel and the development of additional expertise by
existing personnel. The failure to recruit such personnel, loss of such existing
personnel or failure to develop
 
                                        8
<PAGE>   10
 
such expertise would have a material adverse effect on the Company's business
and financial condition. There can be no assurance that the Company will be able
to retain or recruit needed scientific and professional expertise, particularly
given the Company's currently limited financial resources.
 
PRODUCT LIABILITY AND PRODUCT RECALL
 
     The testing, manufacture, marketing and sale of medical devices entail the
inherent risk of liability claims or product recalls. Although the Company has
not been subject to liability claims or product recalls to date, there can be no
assurances that the Company will not be subject to liability claims or product
recalls for products that have already been distributed or on products to be
distributed in the future. Although the Company maintains product liability
insurance in the United States and in other countries in which the Company
intends to conduct business, including clinical trials and product marketing and
sales, there can be no assurance that such coverage is adequate or will continue
to be available. Product liability insurance is expensive and in the future may
not be available on acceptable terms, if at all. In addition, the Company has
agreed to indemnify certain of its component suppliers for certain potential
product liability. A successful product liability claim or product recall could
inhibit or prevent commercialization of the METRIX System, or cause a
significant financial burden on the Company, or both, and could have a material
adverse effect on the Company's business and financial condition.
 
SHARES ELIGIBLE FOR FUTURE SALE
 
     Sale of substantial amounts of the Company's Common Stock in the public
market or the prospect of such sales could materially and adversely affect the
market price of the Common Stock. As of May 15, 1998, the Company had
outstanding 19,248,193 shares of Common Stock, 7,500 shares of Preferred Stock
convertible into certain of the shares offered hereby and warrants to purchase
102,901 shares of Common Stock. In addition, as of such date, the Company had
granted options to purchase 3,384,984 shares of Common Stock under its 1990
Restated Stock Option Plan, 1994 Stock Option Plan for Nonemployee Directors and
1996 Stock Option Plan for Nonemployee Directors (collectively, the "Stock
Option Plans"). Almost all of the Company's outstanding shares of Common Stock
may be sold without substantial restrictions. Moreover, the Company has filed
with the Commission another registration statement on Form S-3, which registers
for resale an aggregate of 400,000 shares of Common Stock sold in a private
placement. All of the shares purchased under the Stock Option Plans are
available for sale in the public market, subject in some cases to volume and
other limitations.
 
     Sales in the public market of substantial amounts of Common Stock,
including sales of Common Stock issued upon conversion of the Preferred Stock,
or the perception that such sales could occur, could depress prevailing market
prices for the Common Stock. The existence of the private warrants and any other
options or warrants may prove to be a hindrance to future equity financing by
the Company. Further, the holders of such warrants and options may exercise them
at a time when the Company would otherwise be able to obtain additional equity
capital on terms more favorable to the Company.
 
                                        9
<PAGE>   11
 
                              SELLING STOCKHOLDERS
 
     The following table provides certain information regarding the Selling
Stockholders and the number of Shares being offered by them.
 
<TABLE>
<CAPTION>
                                                                                    SHARES BENEFICIALLY OWNED
                                                       SHARES THAT MAY BE SOLD            AFTER OFFERING
                                                    -----------------------------   --------------------------
                             SHARES BENEFICIALLY                  PERCENTAGE OF                  PERCENTAGE OF
                               OWNED PRIOR TO                     COMMON STOCK                   COMMON STOCK
     NAME AND ADDRESS            OFFERING(1)         AMOUNT     OUTSTANDING(1)(2)   AMOUNT(3)     OUTSTANDING
     ----------------        -------------------    ---------   -----------------   ----------   -------------
<S>                          <C>                    <C>         <C>                 <C>          <C>
Advantage Fund II Ltd. ....       1,420,000(4)      1,420,000          6.9%            -0-            -0-
  c/o CITCO
  Kaya Flamboyan 9
  Curacao, Netherlands
  Antilles
 
Koch Industries, Inc.......         946,571           946,571          4.7%            -0-            -0-
  4111 East 37th Street
  North
  Wichita, Kansas 67220
</TABLE>
 
---------------
(1) On April 20, 1998, Advantage Fund II Ltd. and Koch Industries, Inc. acquired
    4,500 and 3,000 shares, respectively, of the Series B Stock in a private
    transaction. Pursuant to the terms of the Certificate of Designations of the
    Series B Stock regarding payment of dividends, the Company may, from time to
    time, issue additional shares of Series B Stock to the Selling Stockholders
    in payment of dividends on the Series B Stock. The number of shares of
    Common Stock shown as beneficially owned and offered by the Selling
    Stockholders represents the number of shares issuable upon conversion of the
    Series B Stock, assuming that the Selling Stockholders do not convert any
    shares of Series B Stock for two years and determined as if the Series B
    Stock and the maximum number of dividend shares issuable during such
    two-year period were converted in full on the date the Registration
    Statement of which this Prospectus forms a part was first filed with the
    Commission. Pursuant to Rule 416 under the Securities Act, the number of
    shares of Common Stock offered by the Selling Stockholders hereby and
    included in the Registration Statement of which this Prospectus is a part
    also includes such presently indeterminate number of additional shares as
    may be issued on conversion of the Preferred Stock pursuant to the
    provisions of the Certificate of Designations of the Series B Stock and the
    Certificate of Designations to be filed for the Preferred Stock issuable
    pursuant to the Commitment Letter regarding determination of the applicable
    conversion price. Accordingly, the actual number of shares of Common Stock
    issued or issuable upon conversion of the Preferred Stock is subject to
    adjustment depending upon factors which cannot be predicted by the Company
    at this time, including, among others, the future market prices of the
    Common Stock, the payment of dividends on the Preferred Stock in additional
    shares of Preferred Stock and the completion of the transaction contemplated
    by the Commitment Letter. Pursuant to the terms of the Certificate of
    Designations of the Series B Stock, the Series B Stock is convertible by
    each holder thereof only to the extent that the number of shares of Common
    Stock then beneficially owned by such holder and its related persons (not
    including shares underlying unconverted shares of Series B Stock) would not
    exceed 4.9% of the then outstanding shares of Common Stock as determined in
    accordance with Sections 13(d) and 16 of the Exchange Act. Accordingly, the
    number of shares of Common Stock set forth for the Selling Stockholder may
    exceed the actual number of shares of Common Stock that the Selling
    Stockholder could own beneficially at any given time through its ownership
    of the Preferred Stock.
 
(2) Computed in accordance with Rule 13d-3(d)(i) promulgated under the Exchange
    Act, and based upon 19,248,193 shares of Common Stock outstanding as of May
    15, 1998, treating as outstanding the number of shares issuable upon the
    assumed conversion by the named Selling Stockholder of the full amount of
    such Selling Stockholders Series B Stock, but not assuming the conversion of
    the Series B Stock of any other Selling Stockholder.
 
(3) Assumes the sale of all the Shares offered by each of the Selling
    Stockholders.
 
(4) Does not include an additional 2,366,571 Shares registered pursuant to the
    Registration Statement of which this Prospectus forms a part, which Shares
    may be issuable upon conversion of the Preferred Stock
 
                                       10
<PAGE>   12
 
    to be issued pursuant to the Commitment Letter. In the event such shares are
    issued as contemplated by the Commitment Letter, an additional 2,366,571
    Shares would be offered pursuant to this Prospectus, together with an
    indeterminate number of additional Shares as may be issued pursuant to the
    Certificate of Designations for such Preferred Stock in accordance with Rule
    416 under the Securities Act.
 
     Neither of the Selling Stockholders has had any material relationship with
the Company, or any of its affiliates, within the past three years.
 
     The Selling Stockholders have represented to the Company that they
purchased the Shares for their own account for investment only and not with a
view towards the public sale or distribution thereof, except pursuant to sales
registered under the Securities Act or exemptions therefrom. In recognition of
the fact that the Selling Stockholders, even though purchasing the Shares for
investment, may wish to be legally permitted to sell their Shares when they deem
appropriate, the Company agreed with the Selling Stockholders to file with the
Commission under the Securities Act the Registration Statement with respect to
the resale of the Shares from time to time in transactions described under "Plan
of Distribution" below, and has agreed to prepare and file such amendments and
supplements to the Registration Statement as may be necessary to keep the
Registration Statement effective until the Shares are no longer required to be
registered for the sale thereof by the Selling Stockholders.
 
                              PLAN OF DISTRIBUTION
 
     All of the Shares offered hereby may be sold from time to time by the
Selling Stockholders, or by their pledgees, donees, transferees or other
successors-in-interest. The sale of the Shares by the Selling Stockholders may
be effected from time to time in transactions in the over-the-counter market
through Nasdaq, or on one or more other securities markets and exchanges, in
privately negotiated transactions, or through a combination of such methods of
sale, at fixed prices that may be changed, at market prices prevailing at the
time of sale, at prices relating to such prevailing market prices or at
negotiated prices. The Selling Stockholders may effect the above-mentioned
transactions by selling the Shares to or through broker-dealers; including block
trades in which brokers or dealers will attempt to sell the Shares to or through
broker-dealers and block trades in which brokers or dealers will attempt to sell
the Shares as agent but may position and resell the block as principal to
facilitate the transaction, or in one or more underwritten offerings on a firm
commitment or best efforts basis. In addition, any of the Shares that qualify
for sale pursuant to Rule 144 promulgated under the Securities Act may be sold
in transactions complying with such Rule 144, rather than pursuant to this
Prospectus.
 
     In order to comply with the securities laws of certain states, if
applicable, the Shares will be sold in such jurisdictions only through
registered or licensed brokers or dealers. In addition, in certain states the
Shares may not be sold unless they have been registered or qualified for sale in
the applicable state or an exemption from the registration or qualification
requirement is available and is complied with.
 
     Any broker-dealers who act in connection with the sale of the Shares
hereunder may be deemed to be "underwriters" within the meaning of Section 2(11)
of the Securities Act, and any commissions received by them and profit on any
resale of the Shares as principal may be deemed to be underwriting discounts and
commissions under the Securities Act. None of the proceeds from the sale of the
Shares by the Selling Stockholders will be received by the Company. The Company
has agreed to bear all expenses (other than selling commissions and fees and
stock transfer taxes) in connection with the registration and sale of the Shares
being offered by the Selling Stockholders. The Company has agreed to indemnify
the Selling Stockholders and broker-dealers who act in connection with the sale
of the Shares hereunder against certain liabilities, including liabilities under
the Securities Act.
 
     To the extent required under the Securities Act, the aggregate amount of
Selling Stockholders' Shares being offered and the terms of the offering, the
names of any such agents, brokers, dealers or underwriters and any applicable
commission with respect to a particular offering will be set forth in an
accompanying Prospectus supplement. Any underwriters, dealers, brokers or agents
participating in the distribution of the Shares may receive compensation in the
form of underwriting discounts, concessions or commissions from the
 
                                       11
<PAGE>   13
 
Selling Stockholders or the purchasers of the Shares for whom such underwriters
or broker-dealers may act as agent or to whom they sell as principal, or both
(which compensation to a particular underwriter or broker-dealer might be in
excess of customary commissions). The Selling Stockholders will be responsible
for all brokerage commissions and other amounts payable with respect to any sale
of Shares with respect to such Selling Stockholders and any legal, accounting or
other expenses incurred.
 
     From time to time, one or more of the Selling Stockholders may transfer,
pledge, hypothecate, donate, assign or grant a security interest in some or all
of the Shares owned by them to lenders or others, and each such person will be
deemed to be a "Selling Stockholder" for purposes of this Prospectus. The number
of Selling Stockholders' Shares beneficially owned by those Selling Stockholders
who so transfer, pledge, donate or assign Selling Stockholders' Shares will
decrease as and when they take such actions. The plan of distribution for
Selling Stockholders' Shares sold hereunder will otherwise remain unchanged,
except that the transferees, pledgees, donees or other successors will be
Selling Stockholders hereunder.
 
     A Selling Stockholder may enter into hedging transactions with
broker-dealers and the broker-dealers may engage in short sales of the Common
Stock in the course of hedging the position they assume with such Selling
Stockholder, including, without limitation, in connection with distributions of
the Common Stock by such broker-dealers. In addition, a Selling Stockholder may,
from time to time, sell short the Common Stock of the Company, and in such
instances, this Prospectus may be delivered in connection with such short sales
and the Shares offered hereby may be used to cover such short sales. A Selling
Stockholder may also enter into options or other transactions with
broker-dealers that involve the delivery of the Common Stock to the
broker-dealers, who may then resell or otherwise transfer such Common Stock. A
Selling Stockholder may also loan or pledge the Common Stock to a broker-dealer
and the broker-dealer may sell the Common Stock so loaned or, upon a default,
may sell or otherwise transfer the pledged Common Stock.
 
     Under applicable rules and regulations under the Exchange Act, any person
engaged in the distribution of the Shares may not bid for or purchase shares of
Common Stock during a period which commences one business day (five business
days if the Company's public float is less than $25 million or its average daily
trading volume is less than $100,000) prior to such person's participation in
the distribution, subject to exceptions for certain passive market making
activities. In addition and without limiting the foregoing, each Selling
Stockholder will be subject to applicable provisions of the Exchange Act and the
rules and regulations thereunder, including without limitation, Regulation M,
which provisions may limit the timing of purchases and sales of shares of the
Company's Common Stock by such Selling Stockholder.
 
     There can be no assurance that the Selling Stockholders will sell any or
all of the Shares offered by them hereunder.
 
                                 LEGAL MATTERS
 
     The validity of the Common Stock offered hereby has been passed upon for
the Company by Perkins Coie, Seattle, Washington.
 
                                    EXPERTS
 
     The consolidated financial statements of the Company appearing in the
Company's Annual Report (Form 10-K) for the year ended December 31, 1997, have
been audited by Ernst & Young LLP, independent auditors, as set forth in their
report thereon (which contains an explanatory paragraph describing conditions
that raise substantial doubt about the Company's ability to continue as a going
concern as described in Note 1 to the consolidated financial statements)
included therein and incorporated herein by reference. Such consolidated
financial statements are incorporated herein by reference in reliance upon such
report given upon the authority of such firm as experts in accounting and
auditing.
 
                                       12
<PAGE>   14
 
======================================================
 
     NO DEALER, SALESPERSON OR OTHER PERSON HAS BEEN AUTHORIZED TO GIVE ANY
INFORMATION OR TO MAKE ANY REPRESENTATIONS OTHER THAN THOSE CONTAINED IN THIS
PROSPECTUS IN CONNECTION WITH THE OFFERING HEREIN CONTAINED AND, IF GIVEN OR
MADE, SUCH INFORMATION OR REPRESENTATIONS MUST NOT BE RELIED UPON AS HAVING BEEN
AUTHORIZED BY THE COMPANY. THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO SELL,
OR A SOLICITATION OF AN OFFER TO BUY, THE SHARES OFFERED HEREBY IN ANY
JURISDICTION TO ANY PERSON TO WHOM IT IS UNLAWFUL TO MAKE AN OFFER OR
SOLICITATION. NEITHER THE DELIVERY OF THIS PROSPECTUS NOR ANY SALE MADE
HEREUNDER SHALL, UNDER ANY CIRCUMSTANCES, CREATE AN IMPLICATION THAT THERE HAS
BEEN NO CHANGE IN THE AFFAIRS OF THE COMPANY SINCE THE DATE HEREOF.
 
                            ------------------------
 
<TABLE>
<CAPTION>
                                        PAGE
                                        ----
<S>                                     <C>
Available Information.................    2
Forward-Looking Statements............    2
Incorporation of Certain Documents by
  Reference...........................    2
Risk Factors..........................    4
Selling Stockholders..................    9
Plan of Distribution..................   10
Legal Matters.........................   12
Experts...............................   12
</TABLE>
 
======================================================
======================================================
 
                                INCONTROL, INC.
 
                              4,733,142 SHARES OF
                                  COMMON STOCK
 
                            ------------------------
 
                                   PROSPECTUS
                            ------------------------
                                  MAY   , 1998
 
======================================================
<PAGE>   15
 
                                    PART II
 
                     INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION
 
     The following table sets forth the estimated expenses of the registrant in
connection with the issuance and distribution of the securities being registered
(all amounts are estimated except the Securities and Exchange Commission
registration fee). Selling commissions and fees and stock transfer taxes are
payable individually by the Selling Stockholders.
 
<TABLE>
<S>                                                           <C>
Securities and Exchange Commission registration fee.........  $ 5,891
Blue sky filing fees and expenses...........................    5,000
Legal fees and expenses.....................................   10,000
Accountants' fees and expenses..............................    3,000
Miscellaneous expenses......................................    1,109
                                                              -------
          Total.............................................  $25,000
                                                              =======
</TABLE>
 
ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
     Section 145 of the Delaware General Corporation Law (the "DGCL") provides
that a corporation may indemnify directors and officers as well as other
employees and individuals against expenses (including attorneys' fees),
judgments, fines and amounts paid in settlement in connection with specified
actions, suits or proceedings, whether civil, criminal, administrative or
investigative (other than an action by or in the right of the corporation, i.e.,
a "derivative action") if they acted in good faith and in a manner they
reasonably believed to be in, or not opposed to, the best interests of the
corporation, and, with respect to any criminal action or proceeding, had no
reasonable cause to believe their conduct was unlawful. A similar standard is
applicable in the case of derivative actions, except that (i) indemnification
only extends to expenses (including attorneys' fees) incurred in connection with
the defense or settlement of such actions and (ii) the statute requires court
approval before there can be any indemnification where the person seeking
indemnification has been found liable to the corporation. The statute provides
that it is not exclusive of other indemnification that may be granted by a
corporation's charter, bylaws, disinterested director vote, stockholder vote or
otherwise.
 
     Section 10 of the registrant's Amended and Restated Bylaws (the "Bylaws")
requires indemnification to the fullest extent permitted under Delaware law as
from time to time in effect. Subject to any restrictions imposed by Delaware
law, the Bylaws provide an unconditional right to indemnification for all
expense, liability and loss (including attorneys' fees, judgments, fines, ERISA
excise taxes or penalties and amounts paid in settlement) actually and
reasonably incurred or suffered by any person in connection with any actual or
threatened action, suit or proceeding, whether civil, criminal, administrative
or investigative, by reason of the fact that such person is or was serving as a
director or officer of the registrant or that, being or having been a director
or officer or an employee of the registrant, such person is or was serving at
the request of the registrant as a director, officer, employee or agent of
another corporation, partnership, joint venture, trust or other enterprise,
including an employee benefit plan. The Bylaws also provide that the registrant
may, by action of its Board of Directors, provide indemnification to its
employees and agents with the same scope and effect as the foregoing
indemnification of directors and officers.
 
     Section 102(b)(7) of the DGCL permits a corporation to provide in its
certificate of incorporation that a director of the corporation shall not be
personally liable to the corporation or its stockholders for monetary damages
for breach of fiduciary duty as a director, except for liability for (i) any
breach of the director's duty of loyalty to the corporation or its stockholders,
(ii) acts or omissions not in good faith or that involve intentional misconduct
or a knowing violation of law, (iii) payments of unlawful dividends or unlawful
stock repurchases or redemptions, or (iv) any transaction from which the
director derived an improper personal benefit.
 
                                      II-1
<PAGE>   16
 
     Article 10 of the registrant's Restated Certificate of Incorporation
provides that, to the fullest extent that the DGCL, as it now exists or may
hereafter be amended, permits the limitation or elimination of the liability of
directors, a director of the registrant shall not be liable to the registrant or
its stockholders for monetary damages for breach of fiduciary duty as a
director. Any amendment to or repeal of such Article 10 shall not adversely
affect any right or protection of a director of the registrant for or with
respect to any acts or omissions of such director occurring prior to such
amendment or repeal.
 
     The registrant has entered into an Indemnification Agreement with each of
its executive officers and directors in which the registrant agrees to hold
harmless and indemnify the officer or director to the fullest extent permitted
by Delaware law. Under these Indemnification Agreements, the officer or director
is not indemnified for any action, suit, claim or proceeding instituted by or at
the direction of the officer or director unless such action, suit, claim or
proceeding is or was authorized by the registrant's Board of Directors or unless
the action is to enforce the provisions of the Indemnification Agreement.
 
     No indemnity pursuant to the Indemnification Agreements shall be provided
by the registrant on account of any suit in which a final unappealable judgment
is rendered against an executive officer or director for an accounting of
profits made from the purchase or sale of the registrant's securities by the
executive officer or director in violation of the provisions of Section 16(b) of
the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or for
damages that have been paid directly to the executive officer or director by an
insurance carrier under a directors' and officers' liability insurance policy
maintained by the registrant.
 
ITEM 16. EXHIBITS
 
<TABLE>
<CAPTION>
    EXHIBIT
    NUMBER                            DESCRIPTION
    -------                           -----------
    <C>       <S>
      3.1     Certificate of Designation of Series B Convertible Preferred
              Stock (filed as Exhibit 3.1 to the registrant's Current
              Report on Form 8-K dated April 20, 1998 and incorporated
              herein by reference)
      4.1     Registration Rights Agreement between InControl, Inc. and
              Advantage Fund II Ltd., dated April 16, 1998 (filed as
              Exhibit 4.1 to the registrant's Current Report on Form 8-K
              dated April 20, 1998 and incorporated herein by reference).
      4.2     Registration Rights Agreement between InControl, Inc. and
              Koch Industries, Inc. dated April 16, 1998 (filed as Exhibit
              4.2 to the registrant's Current Report on Form 8-K dated
              April 20, 1998 and incorporated herein by reference).
      5.1     Opinion of Perkins Coie, counsel to the registrant,
              regarding the legality of the Shares.
     23.1     Consent of Ernst & Young LLP, Independent Auditors.
     23.2     Consent of Perkins Coie (contained in Exhibit 5.1).
     24.1     Power of Attorney (contained on signature page).
</TABLE>
 
ITEM 17. UNDERTAKINGS
 
     The undersigned registrant hereby undertakes:
 
          (1) To file, during any period in which offers or sales are being
     made, a post-effective amendment to this registration statement;
 
             (i) To include any prospectus required by Section 10(a)(3) of the
        Securities Act of 1933, as amended (the "Securities Act");
 
             (ii) To reflect in the prospectus any facts or events arising after
        the effective date of the registration statement (or the most recent
        post-effective amendment thereof) which, individually or in the
        aggregate, represent a fundamental change in the information set forth
        in the registration statement; and
 
                                      II-2
<PAGE>   17
 
             (iii) To include any material information with respect to the plan
        of distribution not previously disclosed in the registration statement
        or any material change to such information in the registration
        statement.
 
          (2) That, for the purpose of determining any liability under the
     Securities Act, each such post-effective amendment shall be deemed to be a
     new registration statement relating to the securities offered therein, and
     the offering of such securities at that time shall be deemed to be the
     initial bona fide offering thereof.
 
          (3) To remove from registration by means of a post-effective amendment
     any of the securities being registered that remain unsold at the
     termination of the offering.
 
          (4) That, for purposes of determining any liability under the
     Securities Act, each filing of the registrant's annual report pursuant to
     Section 13(a) or 15(d) of the Exchange Act (and, where applicable, each
     filing of an employee benefit plan's annual report pursuant to Section
     15(d) of the Exchange Act), that is incorporated by reference in the
     registration statement shall be deemed to be a new registration statement
     relating to the securities offered therein, and the offering of such
     securities at that time shall be deemed to be in the initial bona fide
     offering thereof.
 
     Insofar as indemnification for liabilities arising under the Securities Act
may be permitted to directors, officers and controlling persons of the
registrant pursuant to the foregoing provisions, or otherwise, the registrant
has been advised that in the opinion of the Securities and Exchange Commission
such indemnification is against public policy as expressed in the Securities Act
and is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the registrant of expenses
incurred or paid by a director, officer or controlling person of the registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question of whether such indemnification by it is against
public policy as expressed in the Securities Act and will be governed by the
final adjudication of such issue.
 
                                      II-3
<PAGE>   18
 
                                   SIGNATURES
 
     Pursuant to the requirements of the Securities Act of 1933, as amended, the
registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-3 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunder duly
authorized, in the City of Redmond, State of Washington, on the 20th day of May,
1998.
 
                                          INCONTROL, INC.
 
                                          /s/       KURT C. WHEELER
 
                                          --------------------------------------
                                                     Kurt C. Wheeler
                                              Chairman, President and Chief
                                                    Executive Officer
 
                               POWER OF ATTORNEY
 
     Each person whose individual signature appears below hereby authorizes and
appoints Kurt C. Wheeler as attorney-in-fact with full power of substitution, to
execute in the name and on the behalf of each person, individually and in each
capacity stated below, and to file, any and all amendments to this Registration
Statement, including any and all post-effective amendments, and any related Rule
462(b) Registration Statement and any amendment thereto.
 
     Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed by the following persons in the
capacities indicated below on the 20th day of May, 1998.
 
<TABLE>
<CAPTION>
                  SIGNATURE                                        TITLE
                  ---------                                        -----
<C>                                            <S>
 
             /s/ KURT C. WHEELER               Chairman, President and Chief Executive
---------------------------------------------  Officer (Principal Executive Officer)
               Kurt C. Wheeler
 
          /s/ DONALD F. SEATON III             Vice President, Finance, Chief Financial
---------------------------------------------  Officer and Secretary (Principal Financial
            Donald F. Seaton III               and Accounting Officer)
 
             /s/ ALAN D. FRAZIER               Director
---------------------------------------------
               Alan D. Frazier
 
           /s/ DONALD C. HARRISON              Director
---------------------------------------------
             Donald C. Harrison
 
             /s/ MARK B. KNUDSON               Director
---------------------------------------------
               Mark B. Knudson
 
          /s/ MICHAEL J. LEVINTHAL             Director
---------------------------------------------
            Michael J. Levinthal
</TABLE>
 
                                      II-4
<PAGE>   19
 
                                 EXHIBIT INDEX
 
<TABLE>
<CAPTION>
    EXHIBIT
    NUMBER                            DESCRIPTION
    -------                           -----------
    <C>       <S>
      3.1     Certificate of Designation of Series B Convertible Preferred
              Stock (filed as Exhibit 3.1 to the registrant's Current
              Report on Form 8-K dated April 20, 1998 and incorporated
              herein by reference).
      4.1     Registration Rights Agreement between InControl, Inc. and
              Advantage Fund II Ltd., dated April 16, 1998 (filed as
              Exhibit 4.1 to the registrant's Current Report on Form 8-K
              dated April 20, 1998 and incorporated herein by reference).
      4.2     Registration Rights Agreement between InControl, Inc. and
              Koch Industries, Inc. dated April 16, 1998 (filed as Exhibit
              4.2 to the registrant's Current Report on Form 8-K dated
              April 20, 1998 and incorporated herein by reference).
      5.1     Opinion of Perkins Coie, counsel to the registrant,
              regarding the legality of the Shares.
     23.1     Consent of Ernst & Young LLP, Independent Auditors.
     23.2     Consent of Perkins Coie (contained in Exhibit 5.1).
     24.1     Power of Attorney (contained on signature page).
</TABLE>