    <SEC-DOCUMENT>0001564590-18-003257-index.html : 20180226
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    <ACCEPTANCE-DATETIME>20180226165554
    ACCESSION NUMBER:		0001564590-18-003257
    CONFORMED SUBMISSION TYPE:	8-K
    PUBLIC DOCUMENT COUNT:		21
    CONFORMED PERIOD OF REPORT:	20180226
    ITEM INFORMATION:		Results of Operations and Financial Condition
    ITEM INFORMATION:		Other Events
    ITEM INFORMATION:		Financial Statements and Exhibits
    FILED AS OF DATE:		20180226
    DATE AS OF CHANGE:		20180226

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			ARCA biopharma, Inc.
    		CENTRAL INDEX KEY:			0000907654
    		STANDARD INDUSTRIAL CLASSIFICATION:	IN VITRO & IN VIVO DIAGNOSTIC SUBSTANCES [2835]
    		IRS NUMBER:				363855489
    		STATE OF INCORPORATION:			DE
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		8-K
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	000-22873
    		FILM NUMBER:		18641341

    	BUSINESS ADDRESS:
    		STREET 1:		11080 CIRCLEPOINT ROAD
    		STREET 2:		SUITE 140
    		CITY:			WESTMINSTER
    		STATE:			CO
    		ZIP:			80020
    		BUSINESS PHONE:		720-940-2200

    	MAIL ADDRESS:
    		STREET 1:		11080 CIRCLEPOINT ROAD
    		STREET 2:		SUITE 140
    		CITY:			WESTMINSTER
    		STATE:			CO
    		ZIP:			80020

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	NUVELO INC
    		DATE OF NAME CHANGE:	20030203

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	HYSEQ INC
    		DATE OF NAME CHANGE:	19970610
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>8-K
    <SEQUENCE>1
    <FILENAME>abio-8k_20180226.htm
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    <TYPE>EX-99.1
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    <DESCRIPTION>EX-99.1
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