Re: Employment Terms

Exhibit 10.13

December 12, 2005

Matt Borenzweig

Re: Employment Terms

Dear Matt,

CardioMEMS, Inc. (the “Company”) is pleased to offer you the position of Vice President of Sales, on the following terms:

1. Duties; Office Location.

You will be responsible for developing and implementing the Company’s sales strategy, supervising Company’s sales personnel and managing other resources to attain the Company’s sales and financial performance goals. You will report to the Company’s Chief Executive Officer, David Stern and will be a member of the executive team responsible for overall planning and strategic implementation. It is contemplated that your work will be based out of your home office in LA. And that is acceptable to the company in the VP of sales role and will travel and visit customer sites, respective sales territories and Company’s headquarter in Atlanta, Georgia as necessary to fulfill your responsibility.

2. Compensation and Benefits

Your salary shall be $250,000 per annum, subject to payroll deductions and all required withholdings. Your salary will be paid semi-monthly.

In addition to the above salary, you will be eligible for a bonus payment for the calendar year 2006 calculated as follows:

Variable (commission) portion of compensation will be renegotiated for the calendar year 2007.

Sales for calendar year 2006 X [(Sales for 2006/$million) / (1000)]

For example, if sales for 2006 equals $15MM, you are eligible for a bonus equal to $15MM x (15/1000) = $225,000.

Sales for calendar year is such number as is reflected in the Company’s year-end financial statements. 75% of bonus payments may be paid on a quarterly basis based upon the Company’s sales for the quarter as reflected in the Company’s financial statements. The remaining 25% of the bonus payment shall be paid subject to year-end adjustments and audited financial statements reflecting the sales numbers. The balance of the 25% to be paid no later than February 1 ^st 2007.

You will be eligible for the Company’s general employee benefits in accordance with the terms, conditions and limitations of the benefit plans. The Company may modify compensation and benefits from time to time as it deems necessary.

3. Option Grant

After you commence employment, the Company’s board of directors (the “Board”) will grant you an option (“Initial Grant”) to purchase three hundred thousand (300,000) shares of the Company’s common stock.

In addition to the Initial Grant, you will be eligible for two additional option grants (i) to purchase up to one hundred thousand (100,000) shares of the Company common stock if the Company’s sales for the six month period ending June 30, 2006 are at least $6,775,000.00, and (ii) to purchase up to one hundred thousand (100,000) shares of the Company common stock if the Company’s sales for the calendar year 2006 are at least the target amount of $15,000,000, and (iii) to purchase up to one hundred thousand (100,000) shares of the Company common stock if the Company’s sales for the calendar year 2006 are at least the target amount of $19,000,000. You will be eligible for a pro-rated portion of the option grants provided that at least 75% of the sales target amounts for the respective option grant have been achieved. For example, if the 2006 sales equals $12,000,000 (more than 75% of $15MM), you will be eligible for an option grant equal $12MM/$15MM = 80,000 shares.

All options shall be issued under the Company’s current stock option plan (the “Plan”) at fair market value of the stock on the date of grant as determined by the Board. Subject to the acceleration provision set forth below in paragraph 4 below, all option will vest over four (4) years, contingent on your continued employment with the Company, with 25% of the shares to vest on the one year anniversary of your vesting commencement date, and the remaining shares to vest monthly thereafter. The options will be governed by the terms of the Plan and your stock option agreement.

4. Change of Control, Termination following Change of Control

a. Change of Control Acceleration. Subject to the terms and conditions set forth in this paragraph 4, the following acceleration of vesting of the shares subject to any of your outstanding options (“Options”) shall occur upon a Change of Control (as defined below) provided that such Change of Control occurs within one year of your employment commencement date (“Commencement Date”) and you are an employee of the Company at such time; provided, further, that if your employment with the Company is terminated by the Company without Cause (as defined below) within the 30-day period immediately prior to the effective date of the consummation of the Change of Control, then you shall be entitled to the accelerated vesting as set forth below.

In the event of a Change of Control within one year of your Commencement Date, such number of unvested shares subject to your Options shall accelerate and become vested and immediately exercisable such that at least 25% of the shares subject to your Options are vested notwithstanding any cliff vesting or similar requirements. Such acceleration to be effective as of the closing date of such Change of Control. Thereafter, the remaining unvested shares subject to the Option will continue to vest on a monthly basis as set forth in paragraph 3 and subject to paragraph 4(b) below.

b. Acceleration upon Termination following Change of Control.

In the event that your employment is terminated by the Company without Cause or by you for Good Reason (as defined below), in either case, at any time during the 30-day period immediately prior to the effective date of the consummation or within one year following such Change of Control, and you provide the required release of claims described below, then you shall be entitled to the accelerated vesting under your Options as set forth below:

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(i) Termination Within One Year. If the termination occurs within one (1) year of your Commencement Date, you shall receive the accelerated vesting set forth in paragraph 4(a) above and no other acceleration.

(ii) Termination Following Year One and On or Prior to Year Two. If the termination occurs after the first anniversary of the Commencement Date and on or prior to the second anniversary of the Commencement Date, such number of unvested shares subject to your Options shall accelerate and become vested and immediately exercisable as shall equal to fifty (50%) of all unvested shares subject to your Options.

(iii) Termination Following Year Two and On or Prior to Year Three. If the termination occurs after the second anniversary of the Commencement Date and on or prior to the third anniversary of the Commencement Date, such number of unvested shares subject to your Options shall accelerate and become vested and immediately exercisable as shall equal seventy-five (75%) of all unvested shares subject to your Options.

(iii) Termination Following Year Three. If the termination occurs after the third anniversary of the Commencement Date any and all unvested shares subject to your Options shall accelerate and become vested and immediately exercisable.

(c) Definitions.

(i) “Change of Control” shall mean the consummation of any one of the following events: (a) a sale, lease or other disposition of all or substantially all of the assets of the Company; (b) a consolidation or merger of the Company with or into any other corporation or other entity or person, or any other corporate reorganization, in which the shareholders of the Company immediately prior to such consolidation, merger or reorganization, own less than 50% of the Company’s outstanding voting power of the surviving entity following the consolidation, merger or reorganization; or (c) any transaction (or series of related transactions involving a person or entity, or a group of affiliated persons or entities) in which in excess of fifty percent (50%) of the Company’s outstanding voting power is transferred, excluding any consolidation or merger effected exclusively to change the domicile of the Company and excluding any such change of voting power resulting from bona fide equity financing event or public offering of the stock of the Company.

(ii) “Cause” for the Company (or any acquiror or successor in interest thereto) to terminate your employment shall exist if any of the following occurs: (i) your conviction or a plea of nolo contendere of any felony or any other crime involving fraud, dishonesty or moral turpitude; (ii) your commission or attempted commission of or participation in a fraud or act of dishonesty or misrepresentation against the Company that results (or could reasonably be expected to result) in material harm or injury to the business or reputation of the Company; (iii) your material violation of any contract or agreement between you and the Company or any Company policy, or of any statutory duty you owe to the Company, including without limitation, material breach of your proprietary information and inventions agreement with the Company; or (iv) your conduct that constitutes gross insubordination, incompetence or habitual neglect of duties and that results in (or could reasonably be expected to have resulted in) material harm to the business or reputation of the Company; provided, however, that the action or conduct described in clause (iv) above will constitute “Cause” only if such action or conduct

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continues after the Board has provided you with written notice thereof and thirty (30) days opportunity to cure the same, except that the Company is not obligated to provide such written notice and opportunity to cure if the action or conduct is not reasonably susceptible to cure. The determination that a termination is for Cause shall be made in good faith by the Board in its sole reasonable discretion.

(iii) A resignation for “Good Reason” shall mean a resignation of your employment after the occurrence of any of the following events which is not corrected within 15 days after the Company (or any successor thereto) receives written notice from you that any of the following events have occurred and that you assert that grounds for a voluntary termination for Good Reason exist as a result: (i) without your written consent, a material diminution of your duties, position or responsibilities; provided, or (ii) without your written consent, a reduction by the Company in your Base Salary or Performance Bonus as in effect immediately prior to such or (iii) without your written consent, a requirement that you relocate from your current Los Angeles residence more than sixty miles (unless, as a result of such relocation, your principal place of employment is closer to your primary residence than before the relocation).

5. Release Requirements. To be eligible to receive the vesting acceleration set forth in paragraph 4(b) above, you must (i) first timely execute, make effective, and deliver to the Company a general release of all known and unknown claims, in a form reasonably acceptable to the Company; and (ii) not be in material breach of the Employee Proprietary Agreement or any other agreement or contract between you and the Company at the time of the receipt of such benefits.

6. At Will Employment. Your employment with the Company is an “at-will” arrangement and this offer letter agreement does not constitute a guarantee of employment for any specific period of time. This means that either you or the Company may terminate your employment at any time, with or without Cause, and with or without advance notice. This “at-will” employment relationship cannot be changed except in a written agreement approved by the Board and signed by a duly authorized Company officer.

(a) Proprietary Information. As a Company employee, you will be expected to abide by Company rules and regulations and must sign and comply with the Employee Proprietary Agreement, two originals which are attached hereto as Exhibit A.

(b) Third Party Information. In your work for the Company, you will be expected not to use or disclose any confidential information, including trade secrets, of any former employer or other third party to whom you have an obligation of confidentiality. Rather, you will be expected to use only that information which is generally known and used by persons with training and experience comparable to your own, which is common knowledge in the industry or otherwise legally in the public domain, or which is otherwise provided or developed by the Company. You agree that you will not bring onto Company premises or use in your work for the Company, any unpublished documents or property (including but not limited to proprietary information) belonging to any former employer or other third party that you are not authorized to use or disclose. During our discussions about your proposed job duties, you assured us that you would be able to perform those duties within the guidelines just described. By entering into this offer letter agreement, you represent that you will be able to perform your job duties within these guidelines.

(c) Exclusive Property. You agree that all business procured by you and all Company-related business opportunities and plans made known to you while you are employed by the Company, shall remain the permanent and exclusive property of the Company.

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