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<SEC-DOCUMENT>0001209191-09-006981.txt : 20090205
<SEC-HEADER>0001209191-09-006981.hdr.sgml : 20090205
<ACCEPTANCE-DATETIME>20090205171557
ACCESSION NUMBER:		0001209191-09-006981
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20090127
FILED AS OF DATE:		20090205
DATE AS OF CHANGE:		20090205

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Fidler Josh E
		CENTRAL INDEX KEY:			0001300594

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22873
		FILM NUMBER:		09573886

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		410-998-3114

	MAIL ADDRESS:	
		STREET 1:		4750 OWINGS MILLS BLVD.
		CITY:			OWINGS MILLS
		STATE:			MD
		ZIP:			21117

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			JONES ANDREW E
		CENTRAL INDEX KEY:			0001119346

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22873
		FILM NUMBER:		09573885

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		4047208301

	MAIL ADDRESS:	
		STREET 1:		C/O INTERLAND INC
		STREET 2:		101 MARIETTA ST. #200
		CITY:			ATLANTA
		STATE:			GA
		ZIP:			30303

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Roshko Peter
		CENTRAL INDEX KEY:			0001455295

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22873
		FILM NUMBER:		09573882

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		303-444-6950

	MAIL ADDRESS:	
		STREET 1:		C/O BOULDER VENTURES
		STREET 2:		1900 NINTH STREET, STE 200
		CITY:			BOULDER
		STATE:			CO
		ZIP:			80302

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Macks Lawrence M
		CENTRAL INDEX KEY:			0001455470

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22873
		FILM NUMBER:		09573883

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		303-444-6950

	MAIL ADDRESS:	
		STREET 1:		C/O BOULDER VENTURES
		STREET 2:		1900 NINTH STREET, STE 200
		CITY:			BOULDER
		STATE:			CO
		ZIP:			80302

ISSUER:		

	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

	BUSINESS ADDRESS:	
		STREET 1:		8001 ARISTA PLACE
		STREET 2:		SUITE 200
		CITY:			BROOMFIELD
		STATE:			CO
		ZIP:			80021
		BUSINESS PHONE:		720-940-2200

	MAIL ADDRESS:	
		STREET 1:		8001 ARISTA PLACE
		STREET 2:		SUITE 200
		CITY:			BROOMFIELD
		STATE:			CO
		ZIP:			80021

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

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	HYSEQ INC
		DATE OF NAME CHANGE:	19970610

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BOULDER VENTURES IV LP
		CENTRAL INDEX KEY:			0001165196
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22873
		FILM NUMBER:		09573888

	BUSINESS ADDRESS:	
		STREET 1:		1900 NINTH STREET, SUITE 200
		CITY:			BOULDER
		STATE:			CO
		ZIP:			80302
		BUSINESS PHONE:		3034446950

	MAIL ADDRESS:	
		STREET 1:		1900 NINTH STREET, SUITE 200
		CITY:			BOULDER
		STATE:			CO
		ZIP:			80302

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BOULDER VENTURES IV ANNEX LP
		CENTRAL INDEX KEY:			0001165197
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22873
		FILM NUMBER:		09573889

	BUSINESS ADDRESS:	
		STREET 1:		1900 NINTH STREET, SUITE 200
		CITY:			BOULDER
		STATE:			CO
		ZIP:			80302
		BUSINESS PHONE:		3034446950

	MAIL ADDRESS:	
		STREET 1:		1900 NINTH STREET, SUITE 200
		CITY:			BOULDER
		STATE:			CO
		ZIP:			80302

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LEFKOFF KYLE
		CENTRAL INDEX KEY:			0001191818

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22873
		FILM NUMBER:		09573884

	BUSINESS ADDRESS:	
		STREET 1:		BOULDER VENTURES LTD
		STREET 2:		1941 PEARL STREET #300
		CITY:			BOULDER
		STATE:			CO
		ZIP:			80302
		BUSINESS PHONE:		303-381-6600

	MAIL ADDRESS:	
		STREET 1:		3200 WALNUT ST
		CITY:			BOULDER
		STATE:			CO
		ZIP:			80301

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BV PARTNERS IV, L.L.C.
		CENTRAL INDEX KEY:			0001455393
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22873
		FILM NUMBER:		09573887

	BUSINESS ADDRESS:	
		STREET 1:		1900 NINTH STREET, SUITE 200
		CITY:			BOULDER
		STATE:			CO
		ZIP:			80302
		BUSINESS PHONE:		303 444 6950

	MAIL ADDRESS:	
		STREET 1:		1900 NINTH STREET, SUITE 200
		CITY:			BOULDER
		STATE:			CO
		ZIP:			80302

	FORMER NAME:	
		FORMER CONFORMED NAME:	BV Partners IV, L.L.C.
		DATE OF NAME CHANGE:	20090204
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>c80385_3x1.xml
<DESCRIPTION>MAIN DOCUMENT DESCRIPTION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0203</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2009-01-27</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000907654</issuerCik>
        <issuerName>ARCA biopharma, Inc.</issuerName>
        <issuerTradingSymbol>ABIO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001165197</rptOwnerCik>
            <rptOwnerName>BOULDER VENTURES IV ANNEX LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1900 NINTH STREET, STE 200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOULDER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80302</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001165196</rptOwnerCik>
            <rptOwnerName>BOULDER VENTURES IV LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1900 NINTH STREET, STE 200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOULDER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80302</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001455393</rptOwnerCik>
            <rptOwnerName>BV PARTNERS IV, L.L.C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1900 NINTH STREET, STE 200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOULDER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80302</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001300594</rptOwnerCik>
            <rptOwnerName>Fidler Josh E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1900 NINTH STREET, STE 200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOULDER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80302</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001119346</rptOwnerCik>
            <rptOwnerName>JONES ANDREW E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1900 NINTH STREET, STE 200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOULDER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80302</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001191818</rptOwnerCik>
            <rptOwnerName>LEFKOFF KYLE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1900 NINTH STREET, STE 200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOULDER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80302</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001455470</rptOwnerCik>
            <rptOwnerName>Macks Lawrence M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1900 NINTH STREET, STE 200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOULDER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80302</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001455295</rptOwnerCik>
            <rptOwnerName>Roshko Peter</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1900 NINTH STREET, STE 200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOULDER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80302</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>725111</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>48007</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Boulder Ventures IV, L.P.</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Warrant (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>9.7406</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-10-10</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>28651</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Warrant (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>9.7406</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-10-10</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1897</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Boulder Ventures IV, L.P.</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The shares are owned by Boulder Ventures IV (Annex), L.P. (&quot;BV IV Annex&quot;) which is under common control with Boulder Ventures IV, L.P. (&quot;BV IV LP&quot;).  BV Partners IV, L.L.C. (&quot;BV IV LLC&quot;) serves as the sole General Partner of BV IV Annex, and has sole voting and investment control over the respective shares owned by BV IV Annex, and may be deemed to own beneficially the shares held by BV IV Annex.  BV IV LLC however owns no securities of the Issuer directly.  Josh E. Fidler (&quot;Fidler&quot;), Andrew E. Jones (&quot;Jones&quot;), Kyle Lefkoff (&quot;Lefkoff&quot;), Lawrence M. Macks (&quot;Macks&quot;) and Peter Roshko (&quot;Roshko&quot;) are Managing Members of BV IV LLC and share voting and dispositive power over the shares held by BV IV Annex and BV IV LP.  Each of these individuals disclaims beneficial ownership of the shares reported herein, except to the extent of his respective pecuniary interest therein.</footnote>
        <footnote id="F2">The shares are owned by BV IV LP which is under common control with Boulder IV Annex.  BV IV LLC serves as the sole General Partner, and has sole voting and investment control over the respective shares owned by BV IV LP, and may be deemed to own beneficially the shares held by BV IV LP.  BV IV LLC however owns no securities of the Issuer directly.  Fidler, Jones, Lefkoff, Macks and Roshko are Managing Members of BV IV LLC and share voting and dispositive power over the shares held by BV IV LP.  Each of these individuals disclaims beneficial ownership of the shares reported herein, except to the extent of his respective pecuniary interest therein.</footnote>
        <footnote id="F3">Immediately exercisable.</footnote>
    </footnotes>

    <remarks>This report is being filed jointly by Boulder Ventures IV (Annex), L.P., Boulder Ventures IV, L.P., BV Partners IV, L.L.C., Josh E.
Fidler, Andrew E. Jones, Kyle Lefkoff, Lawrence M. Macks and Peter Roshko as of the date hereof and relates to the same transaction.
Exhibit 99.1 Joint Filer Information</remarks>

    <ownerSignature>
        <signatureName>BOULDER VENTURES IV (ANNEX), L.P. By: BV Partners IV, L.L.C., its General Partner By: /s/ Kyle Lefkoff, Managing Member</signatureName>
        <signatureDate>2009-02-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>BOULDER VENTURES IV, L.P. By: BV Partners IV, L.L.C., its General Partner By:/s/ Kyle Lefkoff, Managing Member</signatureName>
        <signatureDate>2009-02-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>BV PARTNERS IV, L.L.C. By:/s/ Kyle Lefkoff, Managing Member</signatureName>
        <signatureDate>2009-02-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Josh E. Fidler</signatureName>
        <signatureDate>2009-02-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Andrew E. Jones</signatureName>
        <signatureDate>2009-02-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Kyle Lefkoff</signatureName>
        <signatureDate>2009-02-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Lawrence M. Macks</signatureName>
        <signatureDate>2009-02-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Peter Roshko</signatureName>
        <signatureDate>2009-02-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
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<DOCUMENT>
<TYPE>EX-99
<SEQUENCE>2
<FILENAME>c80385_99x1.htm
<DESCRIPTION>ADDITIONAL EXHIBITS
<TEXT>
<html>
<head><title>Exhibit 99.1</title></head>
<body><DIV style="font-family: 'Times New Roman',Times,serif; margin-left: .25in; width: 7.20in">

<DIV align="right" style="font-size: 10pt; margin-top: 10pt"><B>Exhibit&nbsp;99.1</B>
</DIV>


<DIV align="center" style="font-size: 10pt; margin-top: 10pt"><B>FORM 3 JOINT FILER INFORMATION</B>
</DIV>

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head --><TR valign="bottom">
    <TD width="30%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="65%">&nbsp;</TD>
</TR>

<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Name of</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&#147;Reporting Persons&#148;:
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Boulder Ventures IV (Annex), L.P. (&#147;BV IV Annex&#148;)</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Boulder Ventures IV, L.P. (&#147;BV IV LP&#148;)</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">BV Partners IV, L.L.C. (&#147;BV IV LLC&#148;)</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Josh E. Fidler (&#147;Fidler&#148;)</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Andrew E. Jones (&#147;Jones&#148;)</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Kyle Lefkoff (&#147;Lefkoff&#148;)</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Lawrence M. Macks (&#147;Macks&#148;)</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Peter Roshko (&#147;Roshko&#148;)</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Address:
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">c/o Boulder Ventures</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">1900 Ninth Street, Suite&nbsp;200</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Boulder, Colorado 80302</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Designated Filer:
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Boulder Ventures IV (Annex), L.P.</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Issuer and</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Ticker Symbol:
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">ARCA biopharma, Inc. (ABIO)</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Date of Event:
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">January&nbsp;27, 2009</TD>
</TR>
<!-- End Table Body --></TABLE>
</DIV>


<DIV align="justify" style="font-size: 10pt; margin-top: 10pt">Each of the following is a Joint Filer with BV IV Annex and may be deemed to share indirect
beneficial ownership in the securities set forth on the attached Form&nbsp;3:
</DIV>

<DIV align="justify" style="font-size: 10pt; margin-top: 10pt">BV IV LLC serves as the sole general partner of BV IV Annex. BV IV LLC has sole voting and
investment control over the respective shares owned by BV IV Annex and may be deemed to own
beneficially the shares held by BV IV Annex. BV IV LLC owns no securities of the Issuer directly.
Fidler, Jones, Lefkoff, Macks and Roshko are Managing Members of BV IV LLC and share voting and
dispositive power over the shares held by BV IV Annex.
</DIV>

<DIV align="justify" style="font-size: 10pt; margin-top: 10pt">BV IV LLC serves as the sole general partner of BV IV LP. BV IV LLC has sole voting and investment
control over the respective shares owned by BV IV LP, and may be deemed to own beneficially the
shares held by BV IV LP. BV IV LLC owns no securities of the Issuer directly. Fidler, Jones,
Lefkoff, Macks and Roshko are Managing Members of BV IV LLC and share voting and dispositive power
over the shares held by BV IV LP.
</DIV>

<DIV align="justify" style="font-size: 10pt; margin-top: 10pt">Each reporting person disclaims beneficial ownership of the shares reported herein, except to the
extent of his respective pecuniary interest therein. The filing of this statement shall not be
deemed an admission that, for purposes of Section&nbsp;16 of the Securities Exchange Act of 1934, or
otherwise, any of the Reporting Persons are the beneficial owner of all of the equity securities
covered by this statement.
</DIV>

</DIV>

<!-- PAGEBREAK -->

<DIV style="font-family: 'Times New Roman',Times,serif; margin-left: .25in; width: 7.20in">

<DIV align="justify" style="font-size: 10pt; margin-top: 10pt">Each of the Reporting Persons listed above has designated Boulder Venture IV (Annex), L.P. as its
designated filer of Forms 3, 4 and 5 in accordance with Section 16(a) of the Securities Exchange
Act of 1934 and the rules thereunder.
</DIV>

<DIV align="justify" style="font-size: 10pt; margin-top: 10pt">BOULDER VENTURES IV, L.P.
</DIV>

<DIV align="justify" style="font-size: 10pt; margin-top: 10pt">By: BV Partners IV, LLC<BR>
Its: General Partner
</DIV>
<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head --><TR valign="bottom">
    <TD width="2%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="32%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="65%">&nbsp;</TD>
</TR>

<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">By:
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">/s/ Kyle Lefkoff
</TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR style="font-size: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top" style="border-top: 1px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Kyle Lefkoff, Managing Member</TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<!-- End Table Body --></TABLE>
</DIV>


<DIV align="justify" style="font-size: 10pt; margin-top: 10pt">BV PARTNERS IV, LLC
</DIV>

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head --><TR valign="bottom">
    <TD width="2%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="32%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="65%">&nbsp;</TD>
</TR>

<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">By:
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">/s/ Kyle Lefkoff
</TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR style="font-size: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top" style="border-top: 1px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Kyle Lefkoff, Managing Member</TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<!-- End Table Body --></TABLE>
</DIV>

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head --><TR valign="bottom">
    <TD width="35%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="60%">&nbsp;</TD>
</TR>

<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">/s/ Josh E. Fidler
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR style="font-size: 1px">
    <TD valign="top" style="border-top: 1px solid #000000"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Josh E. Fidler</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">/s/ Andrew E. Jones</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR style="font-size: 1px">
    <TD valign="top" style="border-top: 1px solid #000000"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Andrew E. Jones</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">/s/ Kyle Lefkoff</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR style="font-size: 1px">
    <TD valign="top" style="border-top: 1px solid #000000"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Kyle Lefkoff</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">/s/ Lawrence M. Macks</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR style="font-size: 1px">
    <TD valign="top" style="border-top: 1px solid #000000"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Lawrence M. Macks</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom" style="padding-top: 1px">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">/s/ Peter Roshko</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR style="font-size: 1px">
    <TD valign="top" style="border-top: 1px solid #000000"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Peter Roshko</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<!-- End Table Body --></TABLE>
</DIV>



<P align="center" style="font-size: 10pt">&nbsp;

<P align="center" style="font-size: 10pt"><!-- Folio -->&nbsp;<!-- /Folio -->
</DIV>





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