Position detection for a circulatory support device

A circulatory support device, comprising:

• a rotor;
• a motor configured to drive rotation of the rotor at one or more speeds;
• a pressure sensor configured to detect a pressure signal;
• and
• at least one controller configured to:
• receive a motor current signal from the motor;
• receive a pressure signal from the pressure sensor;
• generate a normalized motor current signal based, at least in part, on the pressure signal;
• determine a pulsatility of the normalized motor current signal;
• determine whether the circulatory support device is correctly positioned in the heart of the patient based, at least in part, on the pulsatility of the normalized motor current signal;
• and
• output an alarm when it is determined that the circulatory support device is not correctly positioned in the heart of the patient.

A method of determining whether a circulatory support device is correctly positioned in a heart of a patient, the method comprising:

• receiving a motor current signal from a motor of the circulatory support device;
• filtering the motor current signal with a bandpass filter to generate a filtered motor current signal;
• receiving a pressure signal from a pressure sensor arranged on the circulatory support device;
• filtering the pressure signal to generate a filtered pressure signal;
• generating a normalized motor current signal based, at least in part, on the filtered motor current signal and the filtered pressure signal;
• determining a pulsatility of the normalized motor current signal;
• determining a pulsatility of the filtered pressure signal;
• determining a differential pressure signal based, at least in part, on the filtered pressure signal;
• determining that the circulatory support device is not correctly positioned in the heart of the patient when
• (i) the pulsatility of the normalized motor current signal is less than a first threshold value;
• (ii) the pulsatility of the filtered pressure signal is less than a second threshold value;
• (iii) a maximum value of the differential pressure signal within a time window of predetermined length is greater than a third threshold value;
• or
• (iv) a minimum value of the differential pressure signal within the time window is greater than a fourth threshold value;
• and
• outputting an alarm when it is determined that the circulatory support device is not correctly positioned in the heart of the patient.