Direct Epicardial Assist Device using Artificial Rubber Muscle in a Swine Model of Pediatric Dilated Cardiomyopathy

PURPOSE: Ventricular assist devices are a potent alternative or bridge therapy to heart transplants for dilated cardiomyopathy patients. However, ventricular assist devices have problems related to biocompatibility, hemocompatibility, and thromboembolic events, especially in younger patients. The present study examined the hemodynamic effects of a direct cardiac compression device using circumferential artificial rubber muscles in a young swine model of dilated cardiomyopathy. METHODS: Dilated cardiomyopathy was established in 6 pigs (6-8 weeks of rapid right ventricular pacing; average weight, 22.6 ± 2.1 kg). The device was designed using pneumatic rubber muscles (Fluidic Muscle, Festo). Hemodynamic parameters were monitored under baseline conditions, after the assistance, and after inducing ventricular fibrillation. Hemodynamic data were acquired using a PiCCO, multilumened thermodilution catheter in the pulmonary artery, left ventricular pressure monitoring, and epicardial echocardiography. RESULTS: Direct epicardial assistance resulted in a significant improvement in hemodynamic data. Cardiac output improved from 1.39 ± 0.24 L/min to 1.96 ± 0.46 (p = 0.02). Stroke volume (14.5 ± 3.2 mL versus 20.1 ± 4.3 ml, p<0.01) and ejection fraction (25.2 ± 3.6% versus 47.7 ± 7.8%, p<0.01) also improved after assistance. After inducing ventricular fibrillation, cardiac output was maintained at 1.33 ± 0.28 L/min. CONCLUSIONS: Use of a circumferential direct epicardial assistant device resulted in improvement in hemodynamic data in a dilated cardiomyopathy model. Although there is still a need for improvements in device components, the direct cardiac assist device may be a good alternative to recent heart failure device therapies.