Adjustment of long term intraindividual changes in precordial ECG amplitudes
The present disclosure lies in the general field of clinical electrocardiography (ECG), more specifically in ECG methods comprising precordial ECG amplitude measurements. The present invention relates to methods of determining a subject's corrected precordial ECG amplitude from an ECG measurement, which corrections are based on intraindividual changes such as the rotation position of the heart on the horizontal plane, and/or changes in body mass index. The methods are thus useful for adjustment of intraindividual changes over time in precordial ECG amplitudes, such as between two ECG measurements. The present invention further relates to a device, an apparatus and a computer program product, and to uses of said device, apparatus and computer program product in a method of determining a subject's corrected precordial ECG amplitude from an ECG measurement, and for improving the accuracy of electrocardiographic methods depending on precordial ECG amplitude measurements. For example, the methods and the device, apparatus or product can be advantageously used in a method of diagnosing left ventricular hypertrophy and/or hypertension in a subject.
1 . An apparatus ( 601 ) for determining a subject's corrected precordial ECG amplitude in an ECG measurement, comprising:
at least one processor ( 620 ), and
at least one memory ( 630 ) for storing instructions ( 631 ) to be executed by the at least one processor ( 620 ), wherein the at least one memory ( 630 ) and the instructions are configured to, with the at least one processor ( 620 ), cause the apparatus ( 601 ) at least to perform:
maintaining ( 301 ), in said at least one memory, said subject's ECG data obtained from a first ECG measurement made at a first time point, wherein said ECG was recorded using a standardized and reproducible electrode placement method, and wherein said ECG data comprises data for a six lead V 1 -V 6 precordial ECG;
maintaining ( 302 ), in said at least one memory, said subject's ECG data obtained from a second ECG measurement made at a second time point, which is after the first time point, wherein said ECG was recorded using a standardized and reproducible electrode placement method, and wherein said ECG data comprises data for a six lead V 1 -V 6 precordial ECG and a precordial ECG amplitude A;
determining ( 303 ) a percentage correction value R by determining the position of the transition zone in said data of a six lead V 1 -V 6 precordial ECG from said first ECG measurement and assigning ( 303 ) to it a percentage correlation value R1, and determining ( 303 ) the position of the transition zone in said data of a six lead V 1 -V 6 precordial ECG from said second ECG measurement and assigning ( 303 ) to it a percentage correlation value R2, wherein R1 or R2 is independently
(i) about −30% in case the transition zone is between lead V 1 and lead V 2 ,
(ii) about −20% in case the transition zone is around lead V 2 ,
(iii) about −10% in case the transition zone is between lead V 2 and lead V 3 ,
(iv) about 0 in case the transition zone is around lead V 3 or between lead V 3 and lead V 4 ,
(v) about 10% in case the transition zone is around lead V 4 ,
(vi) about 20% in case the transition zone is between lead V 4 and lead V 5 ,
(vii) about 30% in case the transition zone is around lead V 5 , and
(viii) about 40% in case the transition zone is between lead V 5 and lead V 6 ; and calculating ( 303 ) the percentage correction value R using formula (1)
R
=
R
2
-
R
1
;
and
(
1
)
calculating ( 304 ) a subject's corrected precordial ECG amplitude A* from a precordial ECG amplitude value A from said ECG measurement from said second time point, and the percentage correction value R, using formula (2)
A
*
=
A
+
(
R
×
A
)
;
(
2
)
thereby determining said subject's corrected precordial ECG amplitude in the ECG measurement; and
outputting ( 305 ) said subject's corrected precordial ECG amplitude.
2 . The apparatus ( 601 ) of claim 1 , wherein the at least one memory ( 630 ) and the instructions ( 631 ) are configured to, with the at least one processor ( 620 ), cause the apparatus ( 601 ) to further perform:
maintaining ( 501 ), in said at least one memory, a first BMI value of a subject, wherein said first BMI value is obtained from a first time point of a first ECG measurement;
maintaining ( 502 ), in said at least one memory, a second BMI value of said subject, wherein said second BMI value is obtained from a second time point of a second ECG measurement which is after said first time point;
maintaining ( 503 ), in said at least one memory, said subject's ECG data obtained from said first ECG measurement, wherein said ECG was recorded using a standardized and reproducible electrode placement method, and wherein said ECG data comprises data for a six lead V 1 -V 6 precordial ECG;
maintaining ( 504 ), in said at least one memory, said subject's ECG data obtained from said second ECG measurement, wherein said ECG was recorded using a standardized and reproducible electrode placement method, and wherein said ECG data comprises data for a six lead V 1 -V 6 precordial ECG and a precordial ECG amplitude A;
determining ( 505 ) a first percentage correction value B by assigning said first BMI value a first percentage correction value B1, and said second BMI value a second percentage correction value B2, wherein B1 and B2 are independently assigned according to the following table
B1 or B2
BMI
in %
17 or 18
−15
19 or 20
−10
21 or 22
−5
23
0
24 or 25
5
26 or 27
10
28 or 29
15
30 or 31
20
32 or 33
25
34 or 35
30
36 or 37
35
38 or 39
40
40 or 41
45
42 or 43
50
44 or 45
55
46 or 47
60
48 or 49
65
50 or 51
70,
and calculating ( 505 ) the percentage correction value B using formula (3)
B
=
B
2
-
B
1
;
(
3
)
determining ( 506 ) a second percentage correction value R by determining the position of the transition zone in said data of a six lead V 1 -V 6 precordial ECG from said first ECG measurement and assigning ( 506 ) to it a percentage correlation value R1, and determining ( 506 ) the position of the transition zone in said data of a six lead V 1 -V 6 precordial ECG from said second ECG measurement and assigning ( 506 ) to it a percentage correlation value R2, wherein R1 or R2 is independently
(i) about −30% in case the transition zone is between lead V 1 and lead V 2 ,
(ii) about −20% in case the transition zone is around lead V 2 ,
(iii) about −10% in case the transition zone is between lead V 2 and lead V 3 ,
(iv) about 0 in case the transition zone is around lead V 3 or between lead V 3 and lead V 4 ,
(v) about 10% in case the transition zone is around lead V 4 ,
(vi) about 20% in case the transition zone is between lead V 4 and lead V 5 ,
(vii) about 30% in case the transition zone is around lead V 5 , and
(viii) about 40% in case the transition zone is between lead V 5 and lead V 6 ; and calculating ( 506 ) the percentage correction value R using formula (1)
R
=
R
2
-
R
1
;
and
(
1
)
calculating ( 507 ) a subject's corrected precordial ECG amplitude A* from a precordial ECG amplitude value A from said second ECG measurement using formula (5)
A
*
=
A
+
[
(
B
+
R
)
×
A
]
;
(
5
)
thereby determining a subject's corrected precordial ECG amplitude from an ECG measurement; and
outputting ( 508 ) said subject's corrected precordial ECG amplitude.
3 . The apparatus ( 601 ) according to claim 1 , wherein the at least one memory ( 630 ) and the instructions ( 631 ) are configured to, with the at least one processor ( 620 ), cause the apparatus ( 601 ) to perform the outputting ( 305 , 508 ) by:
causing displaying said subject's corrected precordial ECG amplitude in the ECG measurement to a user via a display comprised in or electrically connected to the apparatus; or
outputting said subject's corrected precordial ECG amplitude in the ECG measurement to a second apparatus for displaying said subject's corrected precordial ECG amplitude in the ECG measurement to a user, wherein said second apparatus is connected to the apparatus via at least one communication link and/or at least one communication network.
4 . A computer program product, embodied on a non-transitory computer readable medium, comprising program instructions, that when run is adapted to determine a subject's corrected precordial ECG amplitude in an ECG measurement by performing:
maintaining ( 301 ), in said at least one memory, said subject's ECG data obtained from a first ECG measurement made at a first time point, wherein said ECG data was recorded using a standardized and reproducible electrode placement method, and wherein said ECG data comprises data for a six lead V 1 -V 6 precordial ECG;
maintaining ( 302 ), in said at least one memory, said subject's ECG data obtained from a second ECG measurement made at a second time point, which is after the first time point, wherein said ECG was recorded using a standardized and reproducible electrode placement method, and wherein said ECG data comprises data for a six lead V 1 -V 6 precordial ECG and a pre-cordial ECG amplitude A;
determining ( 303 ) a percentage correction value R by determining the position of the transition zone in said data of a six lead V 1 -V 6 precordial ECG from said first ECG measurement and assigning ( 303 ) to it a percentage correlation value R1, and determining ( 303 ) the position of the transition zone in said data of a six lead V 1 -V 6 precordial ECG from said second ECG measurement and assigning ( 303 ) to it a percentage correlation value R2, wherein R1 or R2 is independently
(i) about −30% in case the transition zone is between lead V 1 and lead V 2 ,
(ii) about −20% in case the transition zone is around lead V 2 ,
(iii) about −10% in case the transition zone is between lead V 2 and lead V 3 ,
(iv) about 0 in case the transition zone is around lead V 3 or between lead V 3 and lead V 4 ,
(v) about 10% in case the transition zone is around lead V 4 ,
(vi) about 20% in case the transition zone is between lead V 4 and lead V 5 ,
(vii) about 30% in case the transition zone is around lead V 5 , and
(viii) about 40% in case the transition zone is between lead V 5 and lead V 6 ; and calculating ( 303 ) the percentage correction value R using formula (1)
R
=
R
2
-
R
1
;
and
(
1
)
calculating ( 304 ) a subject's corrected precordial ECG amplitude A* from a precordial ECG amplitude value A from said ECG measurement from said second time point, and the percentage correction value R, using formula (2)
A
*
=
A
+
(
R
×
A
)
;
(
2
)
thereby determining said subject's corrected precordial ECG amplitude in the ECG measurement; and
causing ( 305 ) outputting said subject's corrected precordial ECG amplitude.