Surgical treatment of persistent atrial fibrillation often fails to restore the transport function of the atrium. This study first introduces the concept of an atrial assist device to restore the pump function of the atrium. A micro motorless pump based on artificial muscle technology, is positioned on the external surface of the atrium to compress it and restore its muscular activity. A bench model reproduces the function of fibrillating atrium to assess the circulatory support that this pump can provide.The Atripump is a dome shape silicone coated nitinol actuator mounted on a plastic ring. A pacemaker-like control unit drives the actuator, which compresses the atrium, providing the mechanical support to the blood circulation. The bench model consists of an open circuit made of latex bladder 60 mm in diameter filled with water. The Atripump is placed on the outer surface of the bladder. Pressure, volume, and temperature changes were recorded.The contraction rate was 1 Hz with power supply of 12 V, 400 mA for 200 milliseconds. Preload ranged from 15 to 21 cm H20. The pump produced a maximal work of 16 x 10(-3) J. Maximal volume pumped was 492 ml/min. This artificial muscle pump is compact, and reproduces the hemodynamic performances of normal atrium.