The Design Of Cardiac Rhythm Synchronized Ventricular Assist Device

Change of life style and high-intensity make the incidence of heartdisease increased gradually, the mortality of heart diseases become thebiggest threat to human health rather than cancer. Basic types of heartdiseases often develop into heart failure. Conservative drug therapy cannotfully cure heart failure, the lack of organ donors and transplant rejectionled scientists gradually turn their gaze to the research and development ofventricular assist devices. Left ventricular assist devices (VAD) is amechanical circulatory support device for partially or completely replacingthe pumping function of the ventricle which can be used to maintain thelife of patients with heart failure as well as helping heart patients aftersurgery to recover cardiac muscle, even permanent treatment of heartfailure, the device has become an important means for the treatment ofheart disease and is of great medical and academic value.Left ventricular assist device drivers is basically controlled by doctorsand trained patients themselves, such devices can roughly meet the needsof the clinical requirement, but this control method has many limitations.Either pulsatile or non-pulsatile ventricular assist devices have constantworking frequency; as a result, the pumping action of VAD often overlapswith heart’s systole, which cause the cardiac afterload timely elevated andincrease heart workload. This is not what we want.This design is based on Shanghai Key scientific research projects（09441901300）, which is proposed to make a synchronous leftventricular assist device driven based on the cardiac rhythm, which cansolve the problems encountered in the aforementioned clinical treatment.The design’s hardware is based on ARM9embedded platform using invasive-borne sensors to obtain real-time arterial pressure data and servomotor as the drive cylinder power unit to drive pulsatile blood pump. Thesoftware system based on the Linux operating system, we developed themodular servo motor driver and ADC driver for the system, the userinterface is based on QT graphics library. The software algorithm includesthe pre-processing of the arterial pressure signal and pulse’s feature pointidentification, which is optimizes according to the real-time requirements,and less consumption of resources is suitable for embedded platforms. Thealgorithm is featured by the real-time processing, compatable withembedded platforms, delay compensation, avoiding arterial pressurebaseline drift effects, recognizing heartbeat disorder. The design canachieve the purpose of synchronization therapy.