Cardiac pump with speed adapted for ventricle unloading
A blood pump system is implantable in a patient for ventricular support. A pumping chamber has an inlet for receiving blood from a ventricle of the patient. An impeller is received in the pumping chamber. A motor is coupled to the impeller for driving rotation of the impeller. A motor controller is provided for tracking systolic and diastolic phases of a cardiac cycle of the patient and supplying a variable voltage signal to the motor in a variable speed mode to produce a variable impeller speed linked to the cardiac cycle. The impeller speed comprises a ramping up to an elevated speed during the diastolic phase in order to reduce a load on the ventricle at the beginning of the systolic phase.
1. A blood pump, comprising:
a chamber;
an impeller disposed within the chamber;
a motor that is configured to drive the impeller; and
at least one processor that:
determines a timing of a cardio cycle of a user; and
varies a speed of the motor based on the timing of the cardio cycle of the user such that a speed of the motor begins ramping down during a systolic phase of the cardio cycle.
2. The blood pump of claim 1 , wherein:
varying the speed of the motor comprises reducing a current level applied to the motor.
3. The blood pump of claim 1 , wherein:
an average speed of the motor is determined based on a physiological state of the user.
4. The blood pump of claim 1 , wherein:
determining the timing of the cardio cycle comprises measuring a time between current peaks.
5. The blood pump of claim 4 , wherein:
the speed of the motor begins ramping down starts at a time after one of the current peaks and before a current minimum value is detected.
6. The blood pump of claim 1 , wherein:
determining the timing of the cardio cycle is based on a signal from a pacemaker.
7. The blood pump of claim 1 , wherein:
the processor varies the speed of the motor based on the timing of the cardio cycle of the user such that a speed of the motor begins ramping up during a diastolic phase of the cardio cycle.
8. A blood pump, comprising:
a chamber;
an impeller disposed within the chamber;
a motor that is configured to drive the impeller; and
at least one processor that:
determines a time period of one or both of a diastolic phase or a time period of a systolic phase of a cardio cycle of a user; and
ramps down a speed of the motor during the systolic phase.
9. The blood pump of claim 8 , wherein:
the speed of the motor is ramped down beginning at a time between about 50% and 90% into the systolic phase.
10. The blood pump of claim 8 , wherein:
the speed of the motor is ramped down to a speed that is based on a physiological state of the user.
11. The blood pump of claim 8 , wherein:
the speed of the motor is ramped down to a substantially constant reduced speed.
12. The blood pump of claim 8 , wherein:
the speed of the motor is ramped down by reducing a current level applied to the motor.
13. The blood pump of claim 8 , wherein:
the time period of one or both of the diastolic phase or the time period of the systolic phase is determined by measuring a time between current peaks.
14. A method for controlling a motor of a blood pump, comprising:
determining a timing of a cardio cycle of a user; and
varying a speed of the motor of the blood pump based on the timing of the cardio cycle of the user such that a speed of the motor begins ramping down during a systolic phase of the cardio cycle.
15. The method for controlling a motor of a blood pump of claim 14 , further comprising:
ramping up a speed of the motor during a diastolic phase of the cardio cycle.
16. The method for controlling a motor of a blood pump of claim 15 , further comprising:
maintaining the speed of the motor for a period of time during the diastolic phase prior to ramping up the speed of the motor.
17. The method for controlling a motor of a blood pump of claim 15 , wherein:
ramping up the speed of the motor begins at a moment between about 50% and 90% into the diastolic phase.
18. The method for controlling a motor of a blood pump of claim 15 , wherein:
the speed of the motor completes ramping up during the systolic phase of the cardio cycle.
19. The method for controlling a motor of a blood pump of claim 14 , wherein:
the speed of the motor completes ramping down during a diastolic phase of the cardio cycle.
20. The method for controlling a motor of a blood pump of claim 14 , wherein:
determining the timing of the cardio cycle is based on a signal from a current sensor of the motor.