Method for determining a cardiac function
A method for determining a cardiac function, comprising (i) determining base anatomical characteristics associated with the subject, (ii) determining pulse delay to a first body site (PD 01 ) and a second body site (PD 02 ) as a function of the anatomical characteristics, wherein the distance via the arterial tree from the aortic valve to the first body site (PD 01 ) is different than the arterial tree distance from the aortic valve to the second body site (PD 02 ), (iii) determining pulse wave velocity between the first body site and the second body site (PWV 12 ), (iv) determining pulse wave velocity between the aortic valve and the first body site (PWV 01 ) as a function of PWV 12 , and the anatomical characteristics; and (v) determining the pre-ejection period (PEP) as a function of PD 01 and PWV 01 .
1. A method for determining a cardiac function associated with a subject, comprising the steps of:
determining base anatomical characteristics associated with the subject;
determining pulse delay to a first body site (PD 01 ) and a second body site (PD 02 ) as a function of the anatomical characteristics, wherein the distance via the arterial tree from the aortic valve to said first body site (PD 01 ) is different than the arterial tree distance from said aortic valve to said second body site (PD 02 );
determining pulse wave velocity between said first body site and said second body site (PWV 12 );
determining pulse wave velocity between said aortic valve and said first body site (PWV 01 ) as a function of said PWV 12 , and said anatomical characteristics; and
determining, using a non-transitory computer readable medium, the pre-ejection period (PEP) as a function of said PD 01 and PWV 01 .
2. The method of claim 1 , wherein said anatomical characteristics comprise the times required for a pressure wave to travel from said aortic valve to said first and second body sites, and said arterial tree distances from said aortic valve to said first and second body sites.
3. The method of claim 1 , wherein said pulse delay to said first body site (PD 01 ) and said second body site (PD 02 ) is determined as a function of said anatomical characteristics and according to the following equations
PD 01 =PEP+ PTT 01
and
PD 02 =PEP+ PTT 02 =PEP+ PTT 01 +( PTT 02 −PTT 01 ),
wherein PEP represents the pre-ejection period, PTT 01 represents the time required for a pressure wave to travel from the aortic valve to the first body site, PTT 02 represents the time required for a pressure wave to travel from the aortic valve to the second body site, and (PTT 02 −PTT 01 ) represents the time required for a pressure wave to travel from the first body site to the second body site.
4. The method of claim 3 , wherein said pulse wave velocity within said arterial region between said first body site and said second body site (PWV 12 ) is determined according to the following equation
PWV
12
=
D
02
-
D
01
PTT
02
-
PTT
01
=
D
02
-
D
01
(
PD
02
-
P
E
P
)
-
(
PD
01
-
P
E
P
)
=
D
02
-
D
01
PD
02
-
PD
01
,
wherein D 01 represents said arterial tree distance from said aortic valve to said first body site, and D 02 represents said arterial tree distance from said aortic valve to said second body site.
5. The method of claim 1 , wherein said pulse wave velocity between said aortic valve and said first body site (PWV 01 ) is determined according to the following equation
PWV 01 =f (PWV 12 ,Patient)
wherein f(PWV 12 ,Patient) represents a patient dependent relationship between said pulse wave velocity between said aortic valve and said first body site and said pulse wave velocity between said first body site and said second body site.
6. The method of claim 1 , wherein said pulse wave velocity between said aortic valve and said first body site (PWV 01 ) is determined according to the following equation
PWV 01 =PWV 12 *α age
wherein α age represents an age dependant relationship between aortic pulse wave velocity and peripheral pulse wave velocity.
7. The method of claim 6 , wherein said age dependant relationship between said aortic pulse wave velocity and said peripheral pulse wave velocity comprises a ratio of said aortic pulse wave velocity to said peripheral pulse wave velocity.
8. The method of claim 5 , wherein said pre-ejection period (PEP) is determined according to the following equation
PEP= PD 01 +PTT 01 ,
wherein
P
T
T
01
=
D
01
P
W
V
01
=
D
01
f
(
P
W
V
12
,
Patient
)
=
D
01
f
(
D
02
-
D
01
P
T
T
02
-
P
T
T
01
,
Patient
)
.
9. The method of claim 7 , wherein said PEP is determined according to the following equation
P
E
P
=
P
D
01
-
D
01
P
W
V
12
*
α
age
=
P
D
01
-
D
01
D
02
-
D
01
P
D
02
-
P
D
01
*
α
age
=
P
D
01
-
(
P
D
02
-
P
D
01
)
*
D
01
(
D
02
-
D
01
)
*
α
age
.
10. A method of determining a cardiac function associated with a subject, comprising the steps of:
determining base anatomical characteristics associated with the subject;
determining pulse delay to a digit (PD Digit ) and an ear (PD Ear ) as a function of said anatomical characteristics;
determining peripheral pulse transit time (PTT Peripheral ) as a function of said PD Digit and PD Ear ;
determining peripheral pulse wave velocity (PWV Peripheral ) as a function of said PTT Peripheral and the arterial distances from the aortic valve to said digit and ear;
determining central pulse wave velocity (PWV Central ) as a function of said PTT Peripheral and a standard ratio of PWV Peripheral to PWV Central (α v ); and
determining, using a non-transitory computer readable medium, the pre-ejection period (PEP) as a function of PWV Central and the arterial said distance from said aortic valve to said ear.
11. The method of claim 10 , wherein said base anatomical characteristics are selected from the group comprising the times required for a pressure wave to travel from the aortic valve to the tip of said digit and a pressure wave to travel from said aortic valve to said ear, and distances from the second intercostal space to suprasternal notch, said suprasternal notch to the base of the right ear, said suprasternal notch to the tip of said digit, and the arterial distances from said aortic valve to said digit and ear.
12. The method of claim 11 , wherein said pulse delay to said digit (PD Digit ) and ear (PD Ear ) on said subject's body is determined as a function of said anatomical characteristics and according to the following equations
PD Digit =PEP+PTT Digit =PEP+PTT Ear +PTT Digit
and
PD Ear =PEP+PTT Ear ,
wherein PEP represents said pre-ejection period, PTT Digit represents said time required for a pressure wave to travel from said aortic valve to said digit, and PTT Ear represents said time required for a pressure wave to travel from said aortic valve to said ear.
13. The method of claim 12 , wherein said PTT Peripheral is determined according to the following equation
PTT Peripheral =PD Digit −PD Ear =PTT Digit −PTT Ear .
14. The method of claim 13 , wherein said peripheral pulse wave velocity (PWV Peripheral ) is determined according to the following equation
PWV
Peripheral
=
D
12
(
PD
Digit
-
PD
Ear
)
,
wherein D 12 represents the difference between the arterial tree distances from said aortic valve to said digit and ear.
15. The method of claim 14 , wherein said central pulse wave velocity (PWV Central ) is determined according to the following equation
PWV
Central
=
α
v
×
PWV
Peripheral
=
D
12
×
α
v
(
PD
Digit
-
PD
Ear
)
.
16. The method of claim 15 , wherein said α v =0.68.
17. The method of claim 15 , wherein said α v is adjusted as a function of age according to the following equation
α
v
=
553
cm
sec
+
(
(
Age
yrs
-
18
yrs
)
×
6.10
cm
sec
/
yrs
817
cm
sec
+
(
(
Age
yrs
-
18
yrs
)
×
0.10
cm
sec
/
yrs
.
18. The method of claim 15 , wherein said PEP is determined according to the following equation
P
E
P
=
PD
Ear
-
D
01
PWV
Peripheral
*
α
v
=
D
01
D
02
-
D
01
PD
Digit
-
PD
Ear
*
α
v
=
(
PD
Digit
-
PD
Ear
)
*
D
01
(
D
02
-
D
01
)
*
α
v
wherein D 01 represents said arterial tree distance from said aortic valve to said ear, and D 02 represents said arterial tree distance from said aortic valve to said digit.
19. A method of determining pre-ejection period (PEP) using a non-transitory computer readable medium, comprising the step of determining PEP according to the following equation
P
E
P
=
PD
Ear
-
D
01
PWV
Peripheral
*
α
v
=
D
01
D
02
-
D
01
PD
Digit
-
PD
Ear
*
α
v
=
(
PD
Digit
-
PD
Ear
)
*
D
01
(
D
02
-
D
01
)
*
α
v
,
wherein PD Ear represents pulse delay to an ear, PD Digit represents pulse delay to a designated digit, D 01 represents arterial tree distance from the aortic valve to said ear, D 02 represents arterial tree distance from said aortic valve to said digit, PWV Peripheral represents peripheral pulse wave velocity, and α v represents a standard ratio of PWV Peripheral to central pulse wave velocity (PWV Central ).