Sec Form 4 Filing - BRISTOW MICHAEL R @ ARCA biopharma, Inc. - 2016-03-01

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person BRISTOW MICHAEL R 2. Issuer Name and Ticker or Trading Symbol ARCA biopharma, Inc. [ ABIO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) See Remarks (Last) (First) (Middle) ARCA BIOPHARMA, INC., 11080 CIRCLEPOINT ROAD, SUITE 140 3. Date of Earliest Transaction (MM/DD/YY) 03/01/2016 (Street) WESTMINSTER, CO80020 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 03/01/2016 S 752 ( 1 ) D $ 3.5 ( 3 ) 45,334 ( 2 ) D Common Stock 19,986 I By Investocor Trust as sole Trustee Common Stock 25,459 I By NFS Custodian for Michael Bristow's IRA

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other BRISTOW MICHAEL R ARCA BIOPHARMA, INC. 11080 CIRCLEPOINT ROAD, SUITE 140 WESTMINSTER, CO80020 X See Remarks Signatures /s/ Brian L. Selby, Attorney-in-Fact 03/02/2016 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents shares of common stock sold pursuant to a Rule 10b5-1 Plan adopted by the Reporting Person for satisfaction of their tax withholding obligation with respect to the vesting of previously reported Restricted Stock Units ("RSUs") granted to the Reporting Person under the Issuer's 2013 Equity Incentive Plan (the "Plan"). ( 2 )Includes (i) remaining 5,952 previously reported shares issued as RSUs under the Plan that vests on 9/17/16, (ii) remaining 4,050 previously reported shares issued as RSUs under the Plan that vest in two equal annual installments beginning on 2/27/17, and (iii) 6,871 previously reported shares issued as RSUs under the Plan that vest in three equal annual installments beginning April 2, 2016, provided that the Reporting Person's continuous service to the Issuer has not been terminated as defined under the Plan; and 28,461 previously reported shares of common stock held directly. ( 3 )The price represents the weighted average sale price for multiple transactions reported on this line. The prices of the transactions ranged from $3.50 to $3.53. Upon request of the SEC staff, ARCA biopharma, Inc. (the "Company") or a security holder of the Company, the reporting person will provide full information regarding the number of shares sold at each separate price.

Remarks: President and Chief Executive Officer

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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