Estimating cardiac parameters when performing an activity using a personalized cardiovascular hemodynamic model

Patent metadata

Field	Value
Publication number	US-2022287572-A1
Application number	US-202117490425-A
Country	US
Kind code	A1
Filing date	Sep 30, 2021
Priority date	Mar 15, 2021
Publication date	Sep 15, 2022
Grant date	—

Abstract

The present disclosure enables personalized cardiac rehabilitation guidance and care continuum using a personalized cardiovascular hemodynamic model that effectively simulates cardiac parameters when the patient performs an activity using a wearable device like a digital watch that can help capture Electrocardiogram (ECG) signal, Photoplethysmogram (PPG) signal and accelerometer signal. The cardiovascular hemodynamic models of the art are not personalized and cannot be input with real time parameters from the subject being monitored. Input parameters including Systemic Vascular Resistance (SVR) using Metabolic EquivalenT (MET) levels associated with an activity level of the subject, unstressed blood volume using an autoregulation method, total blood volume in a body of the subject, and heart rate of the subject are estimated and input to the personalized cardiovascular hemodynamic model to estimate cardiac parameters including cardiac output, ejection fraction and mean arterial pressure.

First claim

What is claimed is:

1 A processor implemented method comprising the steps of:
estimating, via one or more hardware processors, a plurality of input parameters for a personalized cardiovascular hemodynamic model associated with a subject being monitored, the plurality of input parameters comprising (i) Systemic Vascular Resistance (SVR), (ii) unstressed blood volume, (iii) total blood volume in a body of the subject, and (iv) heart rate of the subject, the step of estimating comprises:
estimating the SVR using Metabolic EquivalenT (MET) levels associated with an activity level of the subject; and
updating the unstressed blood volume estimated when the subject is at rest, using an autoregulation method, when an activity is performed by the subject, wherein the autoregulation method comprises:
sensing aortic pressure by baroreceptors located at carotid sinus and aortic arch;
converting the sensed aortic pressure into a neural firing frequency via afferent sympathetic pathways;
generating sympathetic and parasympathetic nervous activities via a central nervous system and efferent pathway depending on the neural firing frequency; and
updating an additional blood demand representing the unstressed blood volume during the activity using the generated sympathetic and parasympathetic nervous activities; and

estimating, via the personalized cardiovascular hemodynamic model, cardiac parameters including cardiac output, ejection fraction and mean arterial pressure, using the estimated plurality of input parameters.

2 . The processor implemented method of claim 1 , wherein the step of estimating a plurality of input parameters is preceded by personalizing a cardiovascular hemodynamic model to obtain the personalized cardiovascular hemodynamic model, the personalizing being based on one or more of (i) cardiac parameters obtained from an echocardiogram, (ii) ECG signal obtained from a wearable device worn by the subject when performing the activity and (iii) metadata of the subject including height and weight associated thereof.

3 . The processor implemented method of claim 2 , wherein the step of estimating a plurality of input parameters comprises sequential activation of a right atrium ra, a left atrium la, a right ventricle rv and a left ventricle lv of the personalized cardiovascular hemodynamic model using compliance functions C ra (t), C la (t), C rv (t) and C lv ,(t) respectively, the compliance functions being defined as:
the compliance function to actuate ra,

C
ra

(
t
)

=

C

min
,
ra

+

0.5
×

(

C

max
,
ra

-

C

min
,
ra

)

⁢

u
⁡
(
t
)

,
wherein

u
⁡
(
t
)

=

{

0
,

0
≤
t
<

T
a

1
-

cos
⁡
(

2
⁢
π
⁢

t
-

T
a

T
-

T
a

)

,

T
a

≤
t
<
T

,

C

min
,
ra

and C max,ra are the minimum and maximum values of the ra compliance, u(t) is the activation function, time t is considered over a complete cardiac cycle, T a is the start of the activation of ra and T is the end of the cardiac cycle;
(ii) the compliance function to actuate la, C la (t)=C min,la +0.5×(C max,la −C min,la )u(t−d la ), wherein C min,la and C max,la are the minimum and maximum values of the la compliance and d la represents a time delay between activation of the ra and the la; and
(iii) the compliance functions to actuate rv and lv are represented as

C
i

(
t
)

=

Assignees

• Tata Consultancy Services Ltd

Inventors

• Roy Dibyendu
• Mazumder Oishee
• Sinha Aniruddha
• Khandelwal Sundeep
• Ghose Avik

Classifications

• A61B5/02438

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

• A61B5/4035

  Evaluating the autonomic nervous system · CPC title

• A61B8/0883

  for diagnosis of the heart · CPC title

• G16H50/50 Primary

  for simulation or modelling of medical disorders · CPC title

• G16H40/63

  for local operation · CPC title