ARCA biopharma, Inc. (ARCA) is a biopharmaceutical company principally focused on developing genetically-targeted therapies for cardiovascular diseases. The Company's lead product candidate is Gencaro (bucindolol hydrochloride), a beta-blocker and mild vasodilator. Gencaro is being evaluated in a clinical trial for the treatment of atrial fibrillation (AF) in patients with heart failure and left ventricular systolic dysfunction (HFREF). Gencaro is part of the beta-blocker class of compounds because of its property of blocking both beta-1 and beta-2, receptors in the heart. The blocking of these receptors prevents the receptor from binding with other molecules, primarily the neurotransmitter norepinephrine (NE), which activate these receptors. The Company is conducting a Phase IIB/III clinical trial of Gencaro, known as GENETIC-AF. Data from the Phase III HF trial of Gencaro in 2,708 heart failure (HF) patients, or the BEST trial, suggested that Gencaro reduces or prevents AF.