Abstract 650: Animal Study Results Support that Biometal Artificial Muscle Restores Atrial Kick and Could Replace Oral Anticoagulation in Permanent Atrial Fibrillation
Treatment of persistent atrial fibrillation (AF) consists of ventricular rhythm control and the use of anticoagulant agents to decrease the high risk of stroke. However, patients under lifetime anticoagulation therapy are exposed to hemorrhagic stroke (1–3% patients/year). The best treatment to prevent stroke may induce stroke itself. Because decreased flow within the fibrillating atrium is associated with spontaneous echo contrast, thrombus formation and embolic events, any device able to restore the atrial kick (AK) should significantly reduce the risk of stroke and eventually improve cardiac output (CO). A motorless, volume displacement pump based on artificial muscle technology could reproduce the AK when placed onto a fibrillating atrium. This study has been designed to assess mechanical effects of this pump on the right cavities in an animal model of AF. Atripump (Nanopowers SA, Switzerland) is a dome shape silicone coated biometal actuator 5 × 45mm. The biometal is electrically actuated by a pacemaker like control unit. In 10 sheep the right atrium (RA) was surgically exposed and the dome sutured onto it. AF was induced with rapid epicardial pacing (600 beats/min). RA ejection fraction (EF) and spontaneous echo contrast was assessed with intracardiac ultrasound in baseline, AF and assisted AF status. A flow meter placed on pulmonary artery measured CO. Results The dome’s contraction rate was 60/min. Mean temperature on the RA was 39±1.5 °C. RA EF was 30% in baseline, 5% in AF and 22% in assisted AF conditions. During the AF state, spontaneous echo contrast was present in all animals and in 2 a thrombus appeared in the right appendix. Neither spontaneous echo contrast nor thrombi were present in baseline and AF assisted status. Thrombi were washed out when the pump was turned on. CO was 5.3±0.3 l/min in baseline, 4.4±0.6 l/min in AF and 5.1±0.3 l/min in assisted AF status (p<0.01). Placed on the right side, the artificial muscle restores the AK, improves CO and shows a mechanical anti coagulant effect. In patients with permanent AF, if implanted on both sides, it would improve CO and prevent embolism of cardiac origin. The implantation technique could be comparable to that of a pacemaker.