Heart beat identification and pump speed synchronization

Patent metadata

Field	Value
Publication number	US-10506935-B2
Application number	US-201816050889-A
Country	US
Kind code	B2
Filing date	Jul 31, 2018
Priority date	Feb 11, 2015
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

A method for synchronizing operation of a heart assist pump device to a patient's cardiac cycle includes obtaining a signal from a motor of a heart assist pump device and filtering the signal to remove noise. The method also includes determining a speed synchronization start point at which time the motor of the heart assist pump device will begin a change in speed of operation based on the filtered signal. The method further includes modulating a speed of the motor of the heart assist pump device to a target speed at the speed synchronization start point, thereby synchronizing the change in speed of operation with a patient's cardiac cycle.

First claim

The invention claimed is:

1. A method comprising:
receiving a signal from a motor of a heart assist pump device;
determining a speed synchronization start point at which time the motor will begin a change in speed of operation based on the signal, wherein determining the speed synchronization start point comprises determining, for at least two prior pulses, whether each of the at least two prior pulses are complete; and
changing a speed of the motor to a target speed at the speed synchronization start point.

2. The method of claim 1 , wherein the signal comprises:
a current signal or a power signal.

3. The method of claim 1 , further comprising filtering the signal, wherein filtering the signal comprises:
employing a second order impulse response filter, an infinite impulse response filter, or a finite impulse response filter.

4. The method of claim 1 , wherein determining whether a pulse is complete is based on at least one selection from a group consisting of:
a mean amplitude of three or more previous pulses;
a maximum amplitude of the pulse;
a minimum amplitude of the pulse;
t f (first falling-crossing time);
t r (first rising-crossing time);
t min (minimum peak time point); and
t max (maximum peak time point).

5. The method of claim 1 , wherein determining whether a pulse is complete comprises:
determining that Diff max2Mean [i] is (1) greater than a first product of c 1 and Diff max2Min [i]; and (2) is lesser than a second product of c 2 and Diff max2Min [i]; and
determining that four pulse periods comprising T f2f [i], T r2r [i], T min2min [i], and T max2max [i] are each (1) greater than T cyc_min , and (2) less than T cyc_max , wherein:
Diff max2Mean [i] is the difference between maximum amplitude and mean data at pulse [i];
c 1 is a first constant coefficient;
c 2 is a second constant coefficient;
T f2f [i] is a pulse period from a last falling-crossing time point to a current falling-crossing time point;
T r2r [i] is a pulse period from a last rising-crossing time point to the current rising-crossing time point;
T min2min [i] is a pulse period from a last minimum time point to a current minimum time point;
T max2max [i] is a pulse period from a last maximum time point to a current maximum time point;
T cyc_min is a minimum limitation of a pulse period of a heart beat;
T cyc_max is a maximum limitation of a pulse period of the heart beat.

6. The method of claim 5 , wherein determining a pulse period comprises:
determining the median of T f2f [i], T r2r [i], T min2min [i], and T max2max [i].

7. The method of claim 1 , wherein determining the speed synchronization start point comprises:
using a maximum amplitude time point as a reference when T max2max [i] is most close to T cyc [i] such that the speed synchronization start point is equal to t max [i]+T cyc [i]−T sp , where T sp is the duration of the increase in speed of operation;
using a minimum amplitude time point as the reference when T min2min [i] is most close to T cyc [i] such that the speed synchronization start point is equal to t min [i]+T cyc [i]+T k1 , where T k1 =k 1 T min2max , and k 1 ≈0.25 to 0.4, which depends on the T sp ;
using a falling-crossing time point as the reference when T f2f [i] is most close to T cyc [i] such that the speed synchronization start point is equal to t f [i+1]+τ f2min +T k1 , where τ f2min is the average of T f2min , and T k1 =k 1 T min2max ; or
using a rising-crossing time point as the reference when T r2r [i] is most close to T cyc [i] such that the speed synchronization start point is equal to t r [i]+T cyc [i]−T k2 where T k2 =k 2 T min2max , and k 2 ≈0.125 to 0.3, which depends on the T sp , wherein:
T max2max [i] is a pulse period from a last maximum time point to a current maximum time point;
T cyc [i] is a period of pulse [i];
t max [i] is a maximum peak time point of pulse [i];
T min2min [i] is a pulse period from a last minimum time point to a current minimum time point;
t min [i] is a minimum peak time point of pulse [i];
T min2max a pulse period from the last minimum time point to the current maximum time point;
T f2f [i] is a pulse period from a last falling-crossing time point to a current falling-crossing time point;
t f [i+1] is a second falling-crossing time;
T f2min is a pulse period from a last falling-crossing to the minimum peak time point;

T r2r [i] is a pulse period from a last rising-crossing time point to the current rising-crossing time point; and
t r [i] is a point at which pulse [i] crosses a mean value on an upslope.

8. The method of claim 1 , wherein the method further comprises:
increasing the speed of operation of the heart assist pump device at additional speed synchronization start points as determined by t sync [j]=t sync [0]−T offset +(j−1)*T cyc [i], where T offset <T min2max and T offset ≈40˜80 ms, wherein:
t sync [j] is
t sync [0] is
T cyc [i] is a period of pulse [i]; and
T min2max a pulse period from the last minimum time point to the current maximum time point.

9. The method of claim 1 , wherein the heart assist pump device comprises:
a left ventricular assist device or a right ventricular assist device.

10. A heart assist pump device, comprising:
a motor; and
a controller, wherein the controller is configured to:
receive frequency range data from the motor;
determine a speed synchronization start point at which time the motor will begin a change in speed of operation based on the frequency range data, wherein determining the speed synchronization start point comprises determining, for at least two prior pulses, whether each of the at least two prior pulses are complete; and
change a speed of the motor to a target speed at the speed synchronization start point.

11. The heart assist pump device of claim 10 , wherein determining whether a pulse is complete is based on at least one selection from a group consisting of:
a mean amplitude of three or more previous pulses;
a maximum amplitude of the pulse;
a minimum amplitude of the pulse;
t f (first falling-crossing time);
t r (first rising-crossing time);
t min (minimum peak time point); and
t max (maximum peak time point).

12. The heart assist pump device of claim 10 , wherein determining whether a pulse is complete comprises:
determining that Diff max2Mean [i] is (1) greater than a first product of c 1 and Diff max2Min [i], and (2) is lesser than a second product of c 2 and Diff max2Min [i]; and
determining that four pulse periods comprising T f2f [i], T r2r [i], T min2min [i], and T max2max [i] are each (1) greater than T cyc_min , and (2) less than T cyc_max , wherein:
Diff max2Mean [i] is the difference between maximum amplitude and mean data at pulse [i];
c 1 is a first constant coefficient;
c 2 is a second constant coefficient;
T f2f [i] is a pulse period from a last falling-crossing time point to a current falling-crossing time point;
T r2r [i] is a pulse period from a last rising-crossing time point to the current rising-crossing time point;
T min2min [i] is a pulse period from a last minimum time point to a current minimum time point;
T max2max [i] is a pulse period from a last maximum time point to a current maximum time point;
T cyc_min is a minimum limitation of a pulse period of a heart beat;
T cyc_max is a maximum limitation of a pulse period of the heart beat.

13. The heart assist pump device of claim 12 , wherein determining a pulse period comprises:
determining the median of T f2f [i], T r2r [i], T min2min [i], and T max2max [i].

14. The heart assist pump device of claim 10 , wherein

Assignees

• Tc1 Llc

Inventors

• Medvedev Alexander
• Yu Shunzhou
• You Ren

Classifications

• A61M1/00

  Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems (catheters A61M25/00; tube connectors, tube couplings, valves or branch units specially adapted for medical use A61M39/00; devices for taking samples of blood A61B5/15; filters implantable into blood vessels A61F2/01) · CPC title

• A61B5/024 Primary

  Measuring pulse rate or heart rate · CPC title

• A61M2205/3334

  Measuring or controlling the flow rate · CPC title

• A61B5/02438 Primary

  with portable devices, e.g. worn by the patient · CPC title

• A61M2230/04

  Heartbeat characteristics, e.g. ECG, blood pressure modulation · CPC title