X0303 4 2009-07-17 1 0000907654 ARCA biopharma, Inc. ABIO 0001392094 Lowe David George C/O SKYLINE VENTURES 525 UNIVERSITY AVENUE, STE 250 PALO ALTO CA 94301 1 0 0 0 Common Stock 2009-07-17 4 S 0 25000 4.1916 D 310400 I See Footnote Common Stock 2009-07-20 4 S 0 102000 4.4370 D 208400 I See Footnote Common Stock 2009-07-21 4 S 0 78800 3.9387 D 129600 I See Footnote The shares are owned directly by Skyline Venture Partners Qualified Purchaser Fund IV, L.P. John G. Freund and Yasunori Kaneko are the Managing Members of Skyline Venture Management IV, LLC, which is the general partner of Skyline Venture Partners Qualified Purchaser Fund IV, L.P. and as such Drs. Freund and Kaneko may be deemed to share voting and dispositive power with respect to all shares of common stock held by Skyline Venture Partners Qualified Purchaser Fund IV, L.P. In addition, Dr. Lowe, one of ARCA's former directors, is a Managing Director of Skyline Ventures and as such may be deemed to share voting and dispositive power with respect to all shares of common stock held by Skyline Venture Partners Qualified Purchaser Fund IV, L.P. Each of Drs. Freund, Kaneko and Lowe disclaim beneficial ownership of such shares except to the extent of his pecuniary interest, if any. /s/ David George Lowe 2009-07-22