<PAGE>



                                                                    Exhibit 10.3


          Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.



CONFIDENTIAL

COPY ONE OF TWO

September 10, 2002

Cambridge Heart, Inc.
One Oak Park Drive
Bedford, MA 01730

Attention: Mr. David Chazanovitz
           President and Chief Executive Officer

Ladies & Gentlemen:

This letter agreement (the "Agreement") will confirm our understanding of the
terms and conditions under which Adams, Harkness & Hill, Inc. (together with its
affiliates, control persons, directors, officers, employees and agents, "AH&H")
is engaged by Cambridge Heart, Inc. ("Cambridge Heart") to provide certain
investment banking and financial advisory services to Cambridge Heart with
respect to consummating one or several possible business combinations, through
purchase, sale, merger, joint venture or otherwise and whether in one or more
transactions through the purchase of an organization's equity, debt securities
or assets, or by means of a merger, consolidation, reorganization, spin-off,
joint venture, partnership, tender offer, exchange offer, purchase, lease,
licensing, arrangement, strategic alliance, or any other transaction of a like
nature, regardless of form (a "Transaction") with another organization
(individually, together with each such organization's respective subsidiaries
and affiliates, the "Target").

1.       SERVICES. Cambridge Heart hereby engages AH&H to act as its financial
         advisor and participate and assist in negotiations with respect to
         exploring, negotiating and consummating a Transaction. As financial
         advisor, AH&H shall perform such financial advisory and investment
         banking services as Cambridge Heart may reasonably request and that
         AH&H deems necessary or appropriate in connection with the Transaction.

         In conjunction with this role, if so requested by the Cambridge Heart
         Board of Directors (the "Board"), AH&H will deliver a written opinion
         (the "Opinion") to the Board as to the fairness, from a financial point
         of view, to the shareholders of Cambridge Heart of the consideration to
         be paid or the exchange ratio to be employed, as the case may be, in
         connection with a Transaction. The Opinion


<PAGE>


CONFIDENTIAL                                                     COPY ONE OF TWO

                                                           Cambridge Heart, Inc.
                                                               September 5, 2002
                                                                          Page 2


          shall be in such form, have such scope and substance and contain such
          assumptions (financial or otherwise), detail, information,
          limitations, qualifications and provisions as AH&H shall determine in
          its sole discretion. The nature and scope of the investigation AH&H
          would conduct to be able to render the Opinion will be such as AH&H
          considers appropriate and consistent with the generally accepted
          standards of practice in the investment banking industry for such
          opinions. The Opinion may be included in any disclosure document filed
          by Cambridge Heart with the Securities and Exchange Commission with
          respect to a proposed Transaction, provided that it is reproduced in
          full, and that any description of or reference to AH&H or summary of
          the Opinion in the disclosure document is in a form reasonably
          acceptable to AH&H and its counsel. It is understood and agreed that
          the Opinion will be addressed to, and be prepared solely for the use
          and benefit of the Board, or a committee thereof, if applicable, and
          may not be relied upon by any other person, and, except as provided
          herein, the Opinion will not be reproduced, summarized or referred to
          in any public document or given to any other person without the prior
          written consent of AH&H.

          Cambridge Heart will furnish and will request the Target to furnish
          AH&H such information as AH&H reasonably requests in connection with
          the performance of its services hereunder (all such information so
          furnished is referred to herein as the "Information"). Cambridge Heart
          understands and agrees that AH&H, in performing its services
          hereunder, will use and rely upon the Information as well as publicly
          available information regarding Cambridge Heart and the Target and
          that AH&H does not assume responsibility for independent verification
          of any information, whether publicly available or otherwise furnished
          to it, including without limitation any financial information,
          forecasts or projections considered by AH&H in connection with the
          rendering of its services. Accordingly, AH&H shall be entitled to
          assume and rely upon the accuracy and completeness of all such
          information and is not required to conduct a physical inspection of
          any of the properties or assets, or to prepare or obtain any
          independent evaluation or appraisal of any of the assets or
          liabilities of Cambridge Heart or the Target. With respect to any
          financial forecasts and projections made available to AH&H by
          Cambridge Heart or the Target and used by AH&H in its analysis, AH&H
          shall be entitled to assume that such forecasts and projections have
          been reasonably prepared on bases reflecting the best currently
          available estimates and judgments of the management of Cambridge Heart
          or the Target, as the case may be, as to the matters covered thereby.

          AH&H agrees that any non-public information relating to Cambridge
          Heart or the Target received by AH&H from or at the direction of
          Cambridge Heart will be used by AH&H solely for the purpose of
          performing its Services and that AH&H


<PAGE>


CONFIDENTIAL                                                     COPY ONE OF TWO

                                                           Cambridge Heart, Inc.
                                                               September 5, 2002
                                                                          Page 3


          will maintain the confidentiality thereof except to the extent (a)
          such information is or becomes otherwise publicly available; (b)
          disclosure thereof is required by law or requested by any governmental
          agency or body (including through a subpoena or other valid legal
          process); or (c) AH&H discloses such information to a party that is
          bound by a confidentiality agreement acceptable to Cambridge Heart.

2.        FEES. In consideration for its services hereunder, Cambridge Heart
          shall pay AH&H, by wire transfer of immediately available funds at the
          time due, the following fees:

          (a)  $[**] payable on October 1, 2002

          (b)  $[**] payable upon delivery to the Board of the Opinion (for a
               specific Transaction involving a specific Target) and $[**]upon
               delivery of each formal affirmation of such Opinion thereof as
               requested by Cambridge Heart;

          (c)  in the event the Board requests, subsequent to the delivery of
               the Opinion described immediately above in subsection (b), an
               opinion associated with a different Transaction involving a
               different Target (the "New Opinion"), $[**] payable upon delivery
               to the Board of the New Opinion and $[**] upon delivery of each
               formal affirmation of the New Opinion thereof as requested by
               Cambridge Heart;

          (d)  upon the Closing of a Transaction, a "Success Fee", which shall
               be payable by wire transfer of immediately available funds equal
               to:

               [**]% of Aggregate Consideration in the case that Aggregate
               Consideration is, when calculated on a per-share basis, less than
               or equal to [**]% of the average closing bid price for Cambridge
               Heart stock for the ten trading days prior to the public
               announcement of a Transaction, or

               [**]% of Aggregate Consideration in the case that Aggregate
               Consideration is, when calculated on a per-share basis, greater
               than [**]% of the average closing market price for Cambridge
               Heart stock for the 15 trading days prior to the public
               announcement of a Transaction; less any amounts previously paid
               specific to that transaction under 2(a), 2(b), and 2(c) above.

          (e)  in the event that funds, identified through Adams Harkness & Hill
               Inc. and derived from investors others than company directors,
               are raised through a debt or equity financing with or without a
               concomitant Transaction, a


<PAGE>


CONFIDENTIAL                                                     COPY ONE OF TWO

                                                           Cambridge Heart, Inc.
                                                               September 5, 2002
                                                                          Page 4


               "Financing Fee" of [**]% of the total gross amount of such debt
               or equity financing.

          Under no circumstances will the Success Fee be less than $[**].

          For purposes of this Agreement, "Closing" shall refer to that date at
          which the final legal transfer of ownership, as set forth in the
          executed definitive asset purchase, stock purchase, merger agreement,
          joint venture, partnership or similar definitive agreement associated
          with the Transaction (the "Definitive Agreement") occurs.

          For purposes of this Agreement, "Aggregate Consideration" shall mean
          the cumulative value of the Transaction, representing the total value
          of Cambridge Heart or the Target, as the case may be, implied by the
          sum of all cash paid or payable and the fair market value of all
          property or securities transferred or transferable directly or
          indirectly, in connection with a Transaction, including (i) cash
          amounts paid or securities issued (or otherwise exchanged or
          transferred) to holders of any warrants, options or stock appreciation
          rights, whether or not vested, or other securities convertible or
          exchangeable for any shares of capital stock; (ii) the total amount of
          indebtedness for borrowed money or similar non-trade liabilities or
          obligations (including pension liabilities, guarantees, capitalized
          leases and the like) repaid, retired, extinguished or assumed in
          connection with a Transaction; and (iii) the fair market value of any
          assets distributed to stockholders or affiliates, at any time after
          the execution of the Definitive Agreement; provided, however, that
          this clause (iii) shall not include or apply to any distribution of
          assets made to stockholders to satisfy tax obligations or liabilities.
          Aggregate Consideration also shall include, in the case of a joint
          venture or similar collaborative undertaking, the total amount of cash
          and fair market value (on the date of Closing) of all property
          contributed by third parties to the joint venture.

          For purposes of calculating Aggregate Consideration: (i) all shares
          will be deemed transferred when a Transaction is effected at Closing
          by the transfer of shares, (A) constituting [**]% or more of the then
          outstanding equity securities of, or equity interest in, the Target or
          Cambridge Heart, as the case may be, or (B) possessing [**]% or more
          of the then outstanding voting power of the outstanding equity
          securities of or equity interest in the Target or Cambridge Heart, as
          the case may be; (ii) the value of any security (as that term is
          defined in the Securities Act of 1933, as amended) issuable in
          connection with a Transaction will be determined, if a publicly-traded
          security, on the basis of the average of the closing prices for the 20
          trading days prior to the Closing, or, if the security is not freely
          tradable (or having no established public market) on the basis of the
          fair market value of such security at Closing as determined in good
          faith by AH&H; and (iii)


<PAGE>


CONFIDENTIAL                                                     COPY ONE OF TWO

                                                           Cambridge Heart, Inc.
                                                               September 5, 2002
                                                                          Page 5


          the value of any property transferred in connection with a Transaction
          will be determined on the basis of the fair market value of such
          property at Closing as determined in good faith by AH&H.

          In the event the terms of a Transaction provide for escrowed,
          contingent or installment payments, AH&H and Cambridge Heart shall
          determine the present value of such payments (discounted at a discount
          rate acceptable to both AH&H and Cambridge Heart) based upon financial
          projections developed in connection with the proposed Transaction, and
          that portion of AH&H's fees payable in respect of such escrowed,
          contingent or installment payments shall be calculated based upon this
          calculated present value of such future payments and shall be paid at
          the Closing. Under no circumstances will any portion of the Success
          Fee be deferred or otherwise not paid in its entirety at Closing.

          While during the course of the engagement contemplated herein, AH&H
          may estimate, for whatever reason, including development of financial
          models for use in negotiations with Target, the amount of the Success
          Fee, the actual amount of the Success Fee will be calculated only at
          Closing and only using the methodology set forth in this Section 2.

          If, in connection with a Transaction that is not completed, Cambridge
          Heart receives a break-up fee, topping fee or other termination fee
          (collectively, a "Termination Fee"), Cambridge Heart will pay AH&H a
          fee equal to [**]% of such Termination Fee at the time such
          Termination Fee is received by Cambridge Heart.

3.        EXPENSES. In addition to any fees that may be payable to AH&H
          hereunder and regardless of whether any Transaction is proposed or
          closed, Cambridge Heart hereby agrees, from time to time upon request,
          to reimburse AH&H for: (a) all reasonable fees and disbursements of
          independent counsel retained by AH&H up to $[**]. Fees greater than
          $[**] may be incurred after prior approval by Cambridge Heart; (b) all
          of AH&H's reasonable travel and related expenses arising out of AH&H's
          engagement hereunder; and (c) all of AH&H's reasonable out-of-pocket
          expenses incurred in connection with any actual or proposed
          Transaction or otherwise arising out of AH&H's engagement hereunder.
          Such expenses are to be paid on a current basis within 30 days of
          receipt of a statement therefore from AH&H.

4.        SCOPE OF RESPONSIBILITY. AH&H shall not be liable to Cambridge Heart
          or to any other person claiming through Cambridge Heart for any claim,
          loss, damage, liability, cost or expense suffered by Cambridge Heart
          or any such other person arising out of or related to AH&H's
          engagement hereunder except for any claim, loss or expense that arises
          primarily out of, or is based primarily upon, any action


<PAGE>


CONFIDENTIAL                                                     COPY ONE OF TWO

                                                           Cambridge Heart, Inc.
                                                               September 5, 2002
                                                                          Page 6


          or failure to act by AH&H that constitutes bad faith, willful
          misconduct or gross negligence on the part of AH&H, other than any
          action or failure to act undertaken at the request, or with the
          consent, of Cambridge Heart. Under no circumstances shall this
          paragraph be modified or amended.

5.        INDEMNIFICATION; CONTRIBUTION. Cambridge Heart agrees to indemnify and
          hold harmless AH&H (together with its affiliates and their respective
          control persons, directors, officers, employees and agents,
          "Indemnified Persons") to the full extent lawful against any and all
          claims, losses, damages, liabilities, costs and expenses as incurred
          (including all reasonable fees and disbursements of counsel and all
          reasonable travel and other out-of-pocket expenses reasonably incurred
          in connection with the investigation of, preparation for and defense
          of any pending or threatened claim, action, proceeding or
          investigation and any litigation or other proceeding arising
          therefrom, to which an Indemnified Person may become subject)
          (collectively, "Damages") arising out of or related to any actual or
          proposed Transaction or AH&H's engagement hereunder; provided,
          however, that there shall be excluded from such indemnification any
          such portion of such Damages as are found in a final judgment by a
          court of competent jurisdiction to have resulted from the willful
          misconduct or gross negligence on the part of the Indemnified Person,
          other than any action undertaken at the request or with the consent of
          Cambridge Heart. The foregoing indemnification obligation is in
          addition to, and not in limitation of, any other rights AH&H may have,
          including but not limited to any right of contribution. In the event
          that the foregoing indemnity is unavailable or insufficient to hold
          harmless an Indemnified Person, then Cambridge Heart shall contribute
          to amounts paid or payable by an Indemnified Person in respect of such
          Damages in such proportion as appropriately reflects the relative
          benefits received by it on the one hand and AH&H on the other. If
          applicable law does not permit allocation solely on the basis of
          benefits, then such contribution shall be made in such proportion as
          appropriately reflects both the relative benefits and relative fault
          of the parties and other relevant equitable considerations. The
          foregoing is subject to the limitation that in no event shall AH&H's
          aggregate contributions in respect of Damages exceed the amount of
          fees actually received by AH&H pursuant to this Agreement. For
          purposes hereof, relative benefits to Cambridge Heart and AH&H of the
          Transaction or other similar transaction shall be deemed to be in the
          same proportion that the total value paid or received or contemplated
          to be paid or received by Cambridge Heart and/or its security holders
          in connection with the Transaction or other similar transaction bears
          to the fees paid to AH&H pursuant to its engagement in respect of such
          Transaction. AH&H shall promptly notify Cambridge Heart of any claim
          or threatened claim being asserted against AH&H which would give rise
          to an indemnification hereunder, and agrees that Cambridge Heart shall
          have the right to participate in the defense of any such


<PAGE>


CONFIDENTIAL                                                     COPY ONE OF TWO

                                                           Cambridge Heart, Inc.
                                                               September 5, 2002
                                                                          Page 7


          claim and, to the extent that Cambridge Heart shall wish, to assume
          the defense thereof and shall pay as incurred the fees and
          disbursements of such counsel related to such proceeding. In any such
          proceeding, AH&H shall have the right to retain its own counsel at
          Cambridge Heart's expense. Cambridge Heart will not enter into any
          waiver, release or settlement with respect to any threatened or
          pending claim, action, proceeding or investigation or settle any
          litigation arising therefrom in respect of which indemnification
          hereunder may be sought (whether or not Indemnified Persons are a
          formal party thereto) without the prior written consent of AH&H (which
          consent shall not be unreasonably withheld or delayed), unless such
          waiver, release or settlement includes an unconditional release of
          AH&H from any and all liability arising out of such threatened or
          pending claim, action, proceeding, investigation or litigation. Under
          no circumstances shall this paragraph be modified or amended.

6.        TERM; TERMINATION OF ENGAGEMENT. The term of this engagement shall be
          for a period of 12 months from the date of this letter, but if at the
          end of such period negotiations or discussions are in progress
          regarding a Transaction, then this engagement shall be automatically
          extended until such time as all negotiations or discussions cease.
          Notwithstanding the foregoing, AH&H's engagement hereunder may be
          terminated by either Cambridge Heart or AH&H at any time, with or
          without cause, upon written notice to that effect to the other party;
          provided, however, that if terminated without Cause:

          (a)  AH&H will be entitled to its full fee under Section 2 hereof in
               the event that (i) at any time prior to the expiration of 12
               months after such termination by Cambridge Heart, a Transaction
               is consummated with a third party identified by AH&H during the
               term of this agreement; or (ii) Cambridge Heart enters into an
               agreement during the term of this Agreement or during such
               subsequent 12 month period contemplating a Transaction with a
               third party identified by AH&H during the term of this agreement
               and such Transaction is ultimately consummated; and

          (b)  the provisions of this Section 6 and of Sections 3, 4 and 5
               hereof shall survive such termination.

          "Cause" shall mean a material breach of this Agreement on the part of
          AH&H, which breach shall not have been cured within a reasonable
          period following written notice to AH&H thereof by Cambridge Heart.

7.        RIGHT OF FIRST REFUSAL. In consideration of AH&H's entering into this
          agreement, Cambridge Heart hereby grants AH&H a right of first refusal
          under which AH&H shall have right of first refusal to provide all
          financial advisory and investment banking services to Cambridge Heart
          during the term of this Agreement and,


<PAGE>


CONFIDENTIAL                                                     COPY ONE OF TWO

                                                           Cambridge Heart, Inc.
                                                               September 5, 2002
                                                                          Page 8


          provided that the agreement has not been terminated by either AH&H or
          Cambridge Heart pursuant to Section 6, for an eight month period
          hereafter, which services shall include but not be limited to: (i)
          acting as financial advisor in connection with any mergers,
          acquisitions, divestitures, spin-offs, and other transactions commonly
          known as mergers and acquisitions transactions; (ii) acting as lead
          underwriter of any public offerings of any form of security relating
          to Cambridge Heart alone and acting as co-lead or co-managing
          underwriter of any public offerings of any form of security relating
          to a successor or merged entity which includes Cambridge Heart Inc.,
          resulting from a Transaction, under economic terms no less favorable
          than any other co-lead or managing underwriter; (iii) acting as
          financial advisor for any private placements of any form of security;
          (iv) delivering fairness opinions and valuations; (v) acting as
          financial advisor for any other extraordinary corporate transactions
          for which Cambridge Heart may engage a financial advisor, such as
          licensing agreements or joint ventures; and (vi) providing other
          general financial advisory and investment banking services as may be
          required by Cambridge Heart during such period. As used herein, a
          right of first refusal shall mean, prior to offering any party other
          than AH&H the right to provide financial advisory and investment
          banking services to Cambridge Heart during the period provided above,
          Cambridge Heart shall be obligated to make an offer to AH&H under
          which AH&H would provide such services, which offer shall clearly
          identify its terms and conditions, and AH&H shall have ten (10)
          business days to accept such offer. If AH&H does not accept such
          offer, then Cambridge Heart shall be free to negotiate and contract
          with any other party with respect to such rights on any terms and
          conditions that are no less favorable to Cambridge Heart than those
          offered to and rejected by AH&H. If Cambridge Heart does not
          consummate an agreement on such terms and conditions as were
          previously offered to AH&H or terms and conditions that are more
          favorable to Cambridge Heart, then the preceding sentence shall again
          apply to any subsequent offer. Any engagement of AH&H to provide
          financial advisory or investment banking services arising from any
          such circumstances is subject to the negotiation and execution by AH&H
          and Cambridge Heart of a separate letter agreement setting forth the
          terms and conditions with respect to AH&H's engagement for that
          transaction. However, unless specifically covered by a separate
          agreement setting forth such arrangement, the
          Indemnification/Assignment Provisions shall apply to each such
          engagement.

8.        GOVERNING LAW; JURISDICTION. This Agreement shall be governed by and
          construed in accordance with the laws of the Commonwealth of
          Massachusetts without regard to the conflicts of law provisions
          thereof. Any right to trial by jury with respect to any claim, action,
          suit or proceeding arising out of this Agreement or any of the matters
          contemplated hereby is waived by Cambridge Heart and AH&H. Cambridge
          Heart hereby submits to the non-exclusive jurisdiction of the


<PAGE>


CONFIDENTIAL                                                     COPY ONE OF TWO

                                                           Cambridge Heart, Inc.
                                                               September 5, 2002
                                                                          Page 9


          Federal and State courts located in Boston, Massachusetts, in
          connection with any dispute related to this Agreement or any of the
          matters contemplated hereby.

9.        RELIANCE ON OTHERS. Cambridge Heart confirms that it will rely on its
          own independent counsel and independent accountants for legal, tax and
          accounting advice.

10.       NO RIGHTS IN SHAREHOLDERS, ETC. Cambridge Heart recognizes that AH&H
          has been engaged only by Cambridge Heart, and that this engagement of
          AH&H is not deemed to be on behalf of and is not intended to confer
          rights upon any shareholder, partner or other owner of Cambridge Heart
          or any other person not a party hereto as against AH&H. Unless
          otherwise expressly agreed, no one other than Cambridge Heart is
          authorized to rely upon this engagement of AH&H or to rely upon any
          statements, advice, opinions or conduct by AH&H. Without limiting the
          foregoing, any opinions or advice rendered to the Board or Cambridge
          Heart's management in the course of this engagement of AH&H hereunder
          are for the purpose of assisting the Board or Cambridge Heart's
          management, as the case may be, in evaluating the Transaction
          contemplated hereby and such opinions or advice do not constitute a
          recommendation to any shareholder of Cambridge Heart concerning action
          that such shareholder might or should take in connection with the
          Transaction contemplated hereby. AH&H's role herein is that of an
          independent contractor and nothing contained herein is intended to
          create or shall be construed as creating a fiduciary relationship
          between Cambridge Heart and AH&H.

11.       ATTORNEY FEES. In the event of any dispute or litigation or other
          proceeding between the parties with respect to any provision of this
          Agreement or arising from the engagement contemplated under this
          Agreement, the prevailing party shall be entitled to recover from the
          non-prevailing party any and all of the reasonable fees and
          disbursements of the prevailing party's attorney to the extent that
          they relate to such dispute, litigation, or other proceeding.

12.       MISCELLANEOUS. Nothing in this Agreement is intended to obligate or
          commit AH&H to provide any services other than as set forth above.
          This Agreement may be executed in counterparts, each of which shall be
          deemed an original, but which together shall be considered a single
          instrument. This Agreement constitutes the entire agreement between
          the parties hereto, and supersedes all prior agreements and
          understandings (both written and oral) of the parties hereto with
          respect to the subject matter hereof, and cannot be amended or
          otherwise modified except in writing executed by the parties hereto.
          The provisions hereof shall inure to the benefit of and be binding
          upon the successors and assigns of Cambridge Heart and AH&H. AH&H may
          refer to the Transaction, after it is public knowledge, in traditional
          "tombstone" announcements or any of its other


<PAGE>


CONFIDENTIAL                                                     COPY ONE OF TWO

                                                           Cambridge Heart, Inc.
                                                               September 5, 2002
                                                                         Page 10


          professional promotional materials. If requested by AH&H, Cambridge
          Heart shall include a mutually acceptable reference to AH&H in any
          press release or other public announcement made by Cambridge Heart
          regarding the Transaction.

If you are in agreement with the foregoing, please sign both copies, retain Copy
One for your records and return Copy Two, whereupon the Agreement shall become
effective as of the date hereof.

Sincerely,

ADAMS, HARKNESS & HILL, INC.

By:  /s/ Jonathan P. Gertler
   -------------------------------------
Jonathan P. Gertler, M.D.
Principal, Group Head - Biomedical Devices and Technology



ACCEPTED AND AGREED:

CAMBRIDGE HEART, INC.

By:    /s/ David Chazanovitz
   -------------------------------------
Mr. David Chazanovitz
President, Chief Executive Officer and Chief Operating Officer