Journal of Human Hypertension (2004) 18, 33–40
& 2004 Nature Publishing Group All rights reserved 0950-9240/04 $25.00
www.nature.com/jhh
ORIGINAL ARTICLE
Electrocardiographic assessment of
left ventricular hypertrophy with
time–voltage QRS and QRST-wave areas
L Oikarinen1,2, M Karvonen2,3, M Viitasalo1, P Takala2,3, M Kaartinen1, J Rossinen1,
I Tierala1,2, H Hänninen1,2, T Katila2,3, MS Nieminen1 and L Toivonen1
1
Division of Cardiology, Helsinki University Central Hospital, Helsinki, Finland; 2BioMag Laboratory,
Helsinki University, Central Hospital, Helsinki, Finland; 3Laboratory of Biomedical Engineering, Helsinki
University of Technology, Helsinki, Finland
The sum of time–voltage QRS areas in the 12-lead
electrocardiogram (ECG) has outperformed other 12lead ECG indices for detection of left ventricular
hypertrophy (LVH). We assessed indices of time–voltage
QRS and T-wave (QRST) areas from body surface
potential mapping (BSPM) for detection of and quantitation of the degree of LVH. We studied 42 patients with
echocardiographic LVH (LVH group) and 11 healthy
controls (controls). QRST area sums were calculated
from 123-lead BSPM and from the 12-lead ECG for
comparison. Leadwise discriminant indices and correlation coefficients were used to identify optimal recording
locations for QRST area-based LVH assessment. BSPM
QRS area sum was greater in the LVH group than in
controls (3752 7 1259 vs 2278 7 627 lV s, respectively;
Po0.001) and at 91% specificity showed 74% sensitivity
for LVH detection. The 12-lead QRS area sum performed
similarly. Taking T-wave areas into account did not
improve the results. QRS area sum from two most
informative leads (located in the upper and lower right
precordium) also separated the LVH group from controls (61.1 7 23.5 vs 27.8 7 6.5 lV s, respectively;
Po0.00001). This 2-lead QRS area sum showed 90%
sensitivity with 100% specificity for LVH detection and
maintained high correlation to indexed left ventricular
mass (r ¼ 0.732; Po0.001). In conclusion, the BSPM QRS
area sum compared to 12-lead QRS area sum does not
substantially improve LVH assessment. The 2-lead QRS
area sum may improve ECG QRS area-based LVH
assessment.
Journal of Human Hypertension (2004) 18, 33–40.
doi:10.1038/sj.jhh.1001631
Keywords: body surface potential mapping; electrocardiogram; left ventricular hypertrophy
Introduction
Both identification of patients with left ventricular
(LV) hypertrophy (LVH) and assessment of the
degree of LVH are clinically important, because
detection of LVH independently predicts cardiovascular morbidity as well as mortality and the relative
risk of these events increases with increasing LV
mass.1–3 Echocardiography and magnetic resonance
imaging, in particular, provide accurate estimates of
anatomic LV mass, but neither of these methods is
applicable to wide-scale screening of LVH.4–6
According to the solid-angle theory, LVH augments QRS voltages on the body surface electrocardiogram (ECG),7 but for clinical purposes QRS
Correspondence: Dr Lasse Oikarinen, Division of Cardiology,
Department of Medicine, Helsinki University Central Hospital,
Haartmaninkatu 4, 00290 Helsinki, Finland.
E-mail: [email protected]
Received 25 February 2003; revised 9 May 2003; accepted 3
August 2003
voltage-based LVH indices fail to identify LVH
patients with sufficient accuracy.8 In the orthogonal-lead signal-averaged ECG, the QRS time–voltage
area in the horizontal plane significantly improves
ECG detection of LVH.9,10 Even better performance
for eccentric LVH detection can be achieved by
summing all the QRS time–voltage areas in the 12lead ECG.11 However, the electrode positioning used
in the 12-lead ECG may not be optimal for QRS areabased LVH detection.12 In addition, the T-wave may
contain information of LV mass not revealed by
restricting the measurements to the QRS complex.12–15
In the present study, our first aim was to assess the
capability of body surface potential mapping
(BSPM) QRS area analysis for detection and quantification of pressure overload-induced LVH compared to the 12-lead ECG QRS area sum as well as to
the Sokolow–Lyon index,16 and to study if calculating QRST areas improves the BSPM methodology.
Our second aim was to identify the optimal
electrode positioning for QRS area-based LVH
ECG detection of left ventricular hypertrophy
L Oikarinen et al
34
assessment and thereby derive a simple, but informative ECG LVH index.
Subjects and methods
Study population
The study population (n ¼ 53) consisted of two
groups. The LVH group (n ¼ 42) included patients
with haemodynamically significant aortic valve
stenosis (n ¼ 27) and patients with essential arterial
hypertension (n ¼ 15), all of whom showed echocardiographic LVH by gender-specific criteria (see
below). The patients with aortic valve stenosis were
being invasively evaluated in the Helsinki University Central Hospital. None of these patients showed
X70% stenosis of luminal diameter of epicardial
coronary arteries in routine coronary angiography.
No patient with essential arterial hypertension had a
history of effort angina. No patient in the LVH group
showed pathological Q-waves in the ECG or regional
wall-motion abnormalities in LV cineangiography or
two-dimensional echocardiography suggesting a
previous myocardial infarction. Patients with a right
or left bundle branch block were not included.
The control subjects (n ¼ 11; controls) were
healthy middle-aged volunteers who were recruited
with a newspaper advertisement. Consecutive subjects who had no major cardiovascular risk factors
and who had no history or signs of cardiovascular
disease were further examined. If they showed a
normal routine echocardiogram and a symptomlimited bicycle exercise test without angina or STsegment changes, they were included as controls.
All patients in both study groups were in sinus
rhythm and none was under medication known to
influence QRS or T-wave morphology. The study
complied with the Declaration of Helsinki. Informed
consent was obtained from all participants and the
study protocol was approved by the ethical review
committee of the Helsinki University Central Hospital.
LV mass) from M-mode measurements made according to the Penn convention.4 Calculated LV mass and
also LV mass indexed to body surface area (to
account for the effect of physiological variation in
LV mass) were both used in the analyses. The
patients included in the LVH group showed indexed
LV mass 4116 g/m2 in men and 4104 g/m2 in
women.18 In patients with echocardiographic LVH,
the LV geometric pattern was considered as concentric if the relative wall thickness19 exceeded 0.43;
otherwise, it was considered to be eccentric.
BSPM
Measurement protocol: The BSPM recording device
and procedure have been described in detail elsewhere.20–22 In brief, the BSPM device records
unipolar potentials with 120 electrodes placed on
the subject’s thorax (Figure 1), and three standard
limb potentials. The recorded signals were digitized
with a sampling frequency of 1 kHz, and selectively
averaged off-line.
LVH measures: From the signal-averaged BSPM
data, the time instants of QRS onset, QRS offset, and
T-wave offset in each lead were determined as
described previously.23,24 The following BSPM indices were calculated in each lead: (1) QRS area by
integrating the absolute value of the BSPM signal
over the QRS complex.11 (2) T-wave area by
integrating the value of the BSPM signal from the
QRS offset to the T-wave offset. To relate this index
Echocardiography
A skilled cardiologist (MaK) performed a standard
M-mode and two-dimensional echocardiography to
all study subjects. Two-dimensionally guided Mmode tracings were recorded from the parasternal
long-axis view with particular care taken to ensure
proper orientation of the ultrasonic beam. Endsystolic and end-diastolic LV wall thicknesses and
dimensions were then measured on a digitizing
table by the cardiologist who was blinded to any
clinical data according to the recommendations of
the American Society of Echocardiography.17 An
average of up to five measurements from consecutive cardiac cycles for each measure was used in the
final analyses. LV mass was calculated with an
anatomically validated formula (r ¼ 0.90 vs autopsy
Journal of Human Hypertension
Figure 1 The electrode layout of the 123-lead body surface
potential mapping system. The electrodes are mounted on 18
strips with a vertical interelectrode distance of 5 cm. The
horizontal spacing of the strips is defined by the individual
thoracic dimensions. The vertical line indicates the level of the
fourth intercostal space. The squares show the locations of the
conventional 12-lead ECG precordial leads V1–V6. The three limb
leads (leads 1–3) are not shown.
ECG detection of left ventricular hypertrophy
L Oikarinen et al
35
value to QRS-T discordance (opposite polarity of
main QRS deflection and T-wave), areas of the Twave in leads with discordant QRS and T waves
were considered negative (Figure 2). (3) QRS-T area
by subtracting the T-wave area parameter from the
QRS area parameter. The rationale of calculating
QRS and T-wave areas differently was based on a
previous study showing that the ECG response to
LVH is flattening of the T-wave or polarity reversal of
the T-wave in relation to the main QRS deflection.13
QRS area sum, T-wave area sum, and QRS-T area
sum were derived by calculating the sum of
respective values from all leads.
Optimal recording locations for QRS area: To
identify the recording locations with the best
discriminative power for LVH detection, we used
the discriminant index (DI).12 In each lead and for
each index, DIs were calculated by subtracting the
control group mean value from the LVH group mean
value. The obtained difference was then divided by
the pooled standard deviation of the study groups to
derive leadwise DIs.12,25 The pooled standard deviation (s) was derived from pooled variance (s2)
calculated by the equation s2 ¼ [(n11)s21+(n21)s22]/
[n1+n22], where s1 and s2 are the standard deviations of the two groups of sizes n1 and n2.12,25,26 A
large DI value indicates good performance of that
lead in separating the LVH patients from the
controls. We then constructed discriminant maps12
displaying DI value distributions over the thorax.
As the DI uses groups based on dichotomized
values, it does not necessarily identify informative
leads for quantification of a continuous parameter,
such as LV mass. Therefore, we also constructed
correlation coefficient maps displaying the correlation coefficient between QRS area and LV mass
index in each lead. In an attempt to derive a simple
index for LVH detection and quantification, we
searched for particularly informative leads with
both good discriminative power between LVH group
and controls as well as with a good correlation
between QRS area and LV mass index for further
analysis.
12-lead ECG
A 12-lead digital ECG was recorded before the BSPM
measurement. However, because in some of the
ECGs there were a few missing leads, we used a
derived 12-lead ECG from the BSPM measurement
in all study subjects. Precordial leads V1–V2 and V4–
V6, as well as bipolar limb leads are part of the
BSPM layout (Figure 1). The signal in precordial
lead V3 was interpolated from four neighbouring
leads (distances E2 cm) and the signals in unipolar
augmented limb leads were calculated according to
standard equations.27
From the averaged 12-lead ECG signal, we
measured the Sokolow–Lyon index (SV1+RV5/V6
(whichever is taller)).16 In each lead, the time–
voltage QRS area was calculated similarly as in the
BSPM leads, and the areas from the 12 leads were
summed (12-lead QRS area sum).11 In patients with
complete measurements, the QRS area sum from the
BSPM-derived 12-lead ECG correlated extremely
closely with that obtained from the original 12-lead
ECG (r ¼ 0.956).
Statistical methods
Statistical data analysis was performed with SPSS
version 10.1 software (SPSS Inc, Chicago, IL, USA).
All continuous data are presented as mean 7 S.D.
The significance of difference in continuous variables between the study groups was determined
with the Mann–Whitney U-test. Correlation between
continuous variables was calculated using Pearson’s
correlation coefficients and using partial correlation
coefficients when adjusting for covariates. All
categorical variables were tested with the w2 test or
with Fisher’s exact test when appropriate. Twotailed P-values o0.05 were considered statistically
significant.
Results
Clinical and echocardiographic characteristics
The clinical and echocardiographic characteristics
of the study groups are shown in Table 1. Of the 42
patients in the LVH group, 33 (78.6%) had concentric and nine (21.4%) eccentric LVH.
Figure 2 Calculation of QRS, T-wave and QRS-T wave areas in
each BSPM lead. QRS area is the sum of absolute values of Q-, Rand S-wave areas. In measurement of the T-wave area, negative
deflections were subtracted from the positive ones (a). If the main
QRS deflection and the T-wave were discordant, the T-wave area
was multiplied by 1 (b). To obtain the QRS-T area, the T-wave
area was subtracted from the QRS area. See text for details.
BSPM and 12-lead ECG indices of LVH in the study
groups
In BSPM, the QRS area sum separated the LVH
group from controls better than T-wave area sum or
Journal of Human Hypertension
ECG detection of left ventricular hypertrophy
L Oikarinen et al
36
Table 1 Clinical and echocardiographic characteristics of the study groups
Gender (male/female)
Age (years)
Body mass index (kg/m2)
Body surface area (m2)
IVS thickness, diastole (cm)
PW thickness, diastole (cm)
LV internal diameter, diastole (cm)
LV mass (g)
LV mass index (g/m2)
Fractional shortening (%)
Controls (n=11)
LVH group (n=42)
P-value
8/3
55 7 7
24.4 7 2.8
1.89 7 0.14
0.85 7 0.21
0.93 7 0.19
4.59 7 0.67
148 7 68
79 7 37
38 7 6
25/17
63 7 12
26.3 7 3.6
1.89 7 0.17
1.44 7 0.32
1.45 7 0.31
5.01 7 0.71
344 7 93
181 7 45
36 7 8
0.503
0.008
0.119
0.878
o0.001
o0.001
0.177
o0.001
o0.001
0.525
Data are given as number of individuals or mean 7 S.D. IVS: interventricular septal; LV: left ventricular; LVH: left ventricular hypertrophy; PW:
posterior wall.
Table 2 Body surface potential mapping and 12-lead ECG indices of left ventricular hypertrophy in the study groups
Controls (n=11)
LVH group (n=42)
P-value
BSPM index
QRS area sum (mV s)
T wave area sum (mV s)
QRS-T area sum (mV s)
2-lead QRS area sum (mV s)
2278.2 7 626.5
412.9 7 1649.2
1865.3 7 1703.8
27.8 7 6.5
3751.7 7 1259.1
1223.4 7 1953.5
4975.2 7 2988.2
61.1 7 23.5
o0.001
0.033
0.002
o0.00001
12-lead ECG index
Sokolow–Lyon voltage (mV)
QRS area sum (mV s)
2.32 7 0.62
344.0 7 85.0
3.96 7 1.37
537.4 7 178.5
o0.001
o0.001
Data are given as mean 7 S.D. BSPM: body surface potential mapping; ECG: electrocardiographic; LVH: left ventricular hypertrophy.
QRS-T area sum (Table 2). In the 12-lead ECG, the
Sokolow–Lyon voltage as well as the QRS area sum
performed equally well as the BSPM QRS area sum
for identifying LVH patients (Table 2). Using the
conventional cutoff value of 3.5 mV, the sensitivity
of Sokolow–Lyon voltage for detection of LVH was
50% with 91% specificity. With matched specificity
of 91% (one false positive in the controls) and
optimizing cutoff points in the present study
population, the sensitivity of the 12-lead QRS area
sum (cutoff value 440 mV s) was 69% and that of
BSPM QRS area sum (cutoff value 3000 mV s) was
74%.
Optimal BSPM leads for QRS area assessment in LVH
detection and quantitation
By use of discriminant maps and correlation maps,
we identified several locations with both a high DI
value for QRS area (Figure 3) and a high correlation
coefficient value between QRS area and LV mass
index. These were leads 12 and 13 on the lower right
precordium, leads 10 and 16 in the upper right
precordium, and lead 82 on the left lower flank area
(see Figure 1). The sum of QRS areas in leads 13 and
16 (2-lead QRS area sum) also separated the LVH
Journal of Human Hypertension
Figure 3 The group mean (GM) and DI maps for QRS area (QRS),
T-wave area (T) and QRS-T area (QRS-T) are displayed over the
thorax. In the GM maps, the solid lines represent positive, dotted
lines negative, and dashed line the zero value of integrals. In the
DI maps, the respective lines represent positive, negative, and
zero values of DI. Contour steps are 20 mV s for GM maps and
0.5 units for DI maps. The best discriminating areas for these
indices can be found on the right and lower parts of the anterior
thorax and on the left flank.
group from controls (Table 2), and the sensitivity for
LVH detection (cutoff value 39 mV s) was 90% with
100% specificity (Figure 4). Other additional sum
combinations from these five leads did not improve
ECG detection of left ventricular hypertrophy
L Oikarinen et al
37
Table 3 Correlation coefficients of left ventricular mass and left
ventricular mass index with body surface potential mapping and
12-lead ECG LVH indices
All subjects (n=53)
LVH group (n=42)
LV mass
LV mass
BSPM index
QRS area sum
0.716*
T wave area sum
0.603*
QRS-T area sum
0.703*
2-lead QRS area sum
0.724*
12-lead ECG index
Sokolow–Lyon
0.539*
QRS area sum
0.669*
LVMI
0.725*
0.591*
0.699*
0.732*
0.582*
0.687*
LVMI
0.633*
0.659*
0.666* 0.666*
0.702*
0.713*
0.608*
0.626*
0.342z
0.582*
0.413w
0.623*
*Po0.001, wPo0.01, zPo0.05. BSA: body surface area; BSPM: body
surface potential mapping; ECG: electrocardiographic; LVH: left
ventricular hypertrophy; LVMI: left ventricular mass indexed to body
surface area.
Figure 4 Scatterplots showing the correlation of 12-lead QRS area
sum (a) and 2-lead QRS area sum (b) to left ventricular mass index
in the overall study population (different markers used in controls
and left ventricular hypertrophy (LVH) patients). The r values are
from the overall study population (n ¼ 53).
the performance. Furthermore, summing up other
additional combinations of QRS area, T-wave area
and/or QRS-T area values from informative leads did
not perform substantially better (data not shown).
Correlation of BSPM and 12-lead ECG QRS area
measures to LV mass and structure
Both in the overall study population and within the
LVH group, the BSPM QRS and QRS-T area sums
showed a stronger correlation to LV mass and LV
mass index than the Sokolow–Lyon voltage, whereas
the BSPM index correlations were only slightly
stronger than or equal to those of the 12-lead QRS
area sum (Table 3). In fact, the BSPM and 12-lead
QRS area sums were almost linearly correlated
(r ¼ 0.967; Po0.001), suggesting that they provide
practically identical information. Scatterplots showing the actual values for BSPM 2-lead QRS area sum
and 12-lead QRS area sum vs LV mass index are
shown Figure 4. In the overall study population,
BSPM QRS area sum and 2-lead QRS area sum
correlated strongly with echocardiographic interventricular septal wall thickness (r ¼ 0.694 and
0.654, respectively; Po0.001 in both) as did also
Sokolow–Lyon voltage and 12-lead QRS area sum
(r ¼ 0.542 and 0.685, respectively; Po0.001 in both).
None of these indices correlated with LV internal
diastolic diameter (r values betweeen 0.085 and
0.103; P40.4 in all). All of the above correlations
remained significant and substantially in the same
order when using partial correlation coefficients
adjusting for the possible effect of age and/or gender
on these parameters.
Discussion
Main findings
Our results show that BSPM QRS area sum can
separate the group of LVH patients without evidence
of coronary artery disease from controls, but for
identifying patients with LVH it does not perform
substantially better than the 12-lead QRS area sum.
The sum of QRS areas from the two most informative leads identified by leadwise BSPM analysis
improved detection of LVH compared to 12-lead
ECG analyses and retained the ability to quantitate
the degree of LVH. Both these leads were located
outside the conventional 12-lead ECG electrode
positions.
Journal of Human Hypertension
ECG detection of left ventricular hypertrophy
L Oikarinen et al
38
BSPM and 12-lead ECG detection and quantitation of
LVH
Detection of patients with LVH is clinically important, because the risk of cardiovascular morbidity
and death is 2–4-fold higher in subjects with LV
mass above normal limits than in those with normal
LV mass.1–3,6,18 In addition, quantification of the
degree of LVH is equally important, since the risk of
these events increases as LV mass increases.2,3 Direct
visualization of the LV wall thicknesses and dimensions by echocardiography enables calculation of LV
mass based on certain geometrical assumptions,4,6
but the accuracy with this methodology is obviously
expertise-dependent. Magnetic resonance imaging
offers accurate assessment of anatomic LV mass, but
the upper normal limits with this methodology have
only recently been established28 and the method
atpresent is unsuitable for screening purposes.5
Therefore, an attempt to develop a widely applicable screening method for LVH assessment is still
warranted.
Pressure-overload of the LV induces myocardial
cellular hypertrophy and, thus, an increase in
electrically active LV mass. According to both
computer simulations and the solid-angle theory,
an increase in LV mass is expected to strengthen
QRS voltage on the body surface ECG.7,13 However,
clinically QRS voltage-based LVH indices in the 12lead ECG fail to identify individual LVH patients
with sufficient accuracy. This may in part be
explained by the effect of several extracardiac
factors, such as age, gender, chest diameter, and
body build, on ECG QRS voltages.8 Attempts to take
these factors into account alone does not suffice for
critical improvement of the methodology. Measuring
only maximum QRS deflection amplitudes overlooks the more powerful discriminating and quantitation capabilities of information in other segments
within the QRS complex.12,29,30 Accordingly, the
time–voltage integrated QRS area in the horizontal
plane from the orthogonal signal-averaged ECG
improves ECG detection of LVH,9,10 and the sum of
QRS areas in the 12-lead ECG results in further
improvement of performance for LVH detection.11
Importantly, the 12-lead QRS area sum may be
relatively independent of extracardiac factors and
gender.11 Even though the QRS area scans the
temporal aspects of the depolarization wavefront,
it is possible that the positioning of the electrodes in
the 12-lead ECG is not spatially optimal for QRS
area-based LVH detection. This is suggested by the
distribution of most informative leads in BSPM
outside the conventional 12-lead ECG electrode
positioning12,29,30 and by the fact that orthogonal
ECG does not capture all the available information
for the assessment of the activation wavefronts.9,10,12,29,30 In addition, the T-wave may contain
complementary information of LV mass,12–15,29,30 but
QRST areas have not been assessed for this purpose.
Methods developed for LVH detection utilizing the
Journal of Human Hypertension
BSPM technique have improved the identification
and even quantification of anatomic LVH,12,29–34
suggesting that accurate assessment of anatomic
LVH from electrical signals is indeed possible.
Based on the above background, we hypothesized
that BSPM mapping of QRS and QRST areas may
improve the detection and quantitation of LVH. In
addition, we determined whether the information
redundancy inherent in BSPM might be compressed
to yield a simple index that could be recorded by a
simple modification of lead placement with the 12lead ECG equipment. Our results show that BSPM
QRS area sum can separate the group of patients
with pressure overload-induced LVH with mostly
concentric LVH from controls and can quantify the
degree of LVH, but the 12-lead QRS area sum is, in
both respects, a very accurate estimate of BSPM QRS
area sum. Furthermore, with the approach we used
taking T-wave areas into consideration does not
improve performance. However, our results suggest
that a simple sum of QRS areas from the upper and
lower right precordial areas improves performance
compared to the 12-lead QRS area sum. Although
this 2-lead QRS area sum was not an a priori index,
the previous BSPM mapping studies have shown
that for QRS voltage measurements the right precordial area is particularly informative for LVH
assessment.12,30 This suggests that our results may
be more generalizable and prompts the prospective
testing of our approach.
Study limitations
An obvious limitation to our study is the relatively
small study population and the use of echocardiography as a reference method,5 since even with
meticulous measurement technique, the assessment
of LV mass with M-mode echocardiography is not
very accurate.35 However, at present screening of
patients for a study like ours with magnetic
resonance imaging is impractical. The numerical
values, including the values of upper limit of
normal, in the article by Okin et al11 should be
treated with caution and their approach was not
tested in an independent test set. Thus, because of
the lack of values for upper normal limits, we
compared our results with matched specificities.
The upper limits of normal should be derived from a
larger sample of unselected subjects and include
investigation of potential gender differences,
although Okin et al11 found their criteria not gender
dependent. Deriving the 2-lead QRS area sum index
from a training set and not testing it subsequently in
an independent test set is likely to optimize the
results. Therefore, to test if the 2-lead QRS area
index truly improves clinical LVH assessment, the
sensitivity and specificity of our approach should be
assessed in a separate population and also including
more patients with borderline LVH. Although with
our approach we found no additional information in
ECG detection of left ventricular hypertrophy
L Oikarinen et al
39
the T-wave area sums, other methods incorporating
separately QRS and T-wave area information or
using, for example, the concept of QRST gradients
may offer additional information from repolarization for LVH assessment.36 Indexing LV mass to body
surface area is an attempt to account for the
variation in physiological determinants of LV mass
and to enable assessment of correlation to pathologically increased LV mass, but has certain limitations.37
Study implications
Our present results show that the 12-lead QRS area
sum captures the same information for LVH detection and quantitation as the BSPM QRS area sum.
The 12-lead QRS area sum performs relatively well
in a study population of patients with mainly
concentric LVH, which has not been previously
shown.11 A simple 2-lead QRS area sum from the
right precordium may be a way to improve ECG
detection of LVH with 12-lead ECG equipment. If
prospectively validated, this index may be useful in
screening patients with LVH and in preliminary
assessment of the degree of LVH as well as in
interventional studies for assessment of regression
of LVH.
Acknowledgements
This work was supported by grants from the Finnish
Foundation for Cardiovascular Research and the
Aarne Koskelo Foundation.
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