US Patent 7520850 Feedback control and ventricular assist devices

Various devices, systems and methods for providing effective, long term and reliable use of pressure feedback in VADs. Exemplary embodiments are described which provide for direct LV pressure measurement, non-invasive calibration techniques to detect ventricular collapse and recalibrate the feedback mechanism, improved pressure sensor designs with reduced drift, and barometric pressure correction schemes. These devices and methods may be used alone or in combination with each other, and may also be combined with other feedback mechanisms.