Minimally Invasive Monitoring of Cardiac Function for Patients with Rotary VAD Support, a Frequency Domain Approach.

A new cardiac function estimation algorithm has been developed to monitor a patient's myocardial contractility while supported by a rotary ventricular device (VAD). This algorithm uses the raw air pressure signal from the cuff pressure sensor, filters the signal with a bandpass filter, and then processes the signal through the Fast Fourier Transform to detect the first and second highest magnitude components. A systematic study by using a computer model to simulate the interaction between the cardiovascular system and the rotary VAD under different contractual states of the heart (failure, recovery, and healthy) demonstrated that these two magnitude components increased when the healthy status of the heart improved. Determination of these two magnitude components does not need any indwelling sensor but an air pressure cuff sensor. Performing this test does not require any interruption of regular rotary VAD operation or cardiac care facility. Successful development of this algorithm would allow more frequent monitoring for patients with less concerns of safety or examination cost, which could potentially improve the outcome of weaning patients from VAD support.