Body Surface Electrocardiographic Mapping
in Inferior Myocardial Infarction
Manifestation of Left and Right Ventricular Involvement
TERRENCE J. MONTAGUE, M.D., ELDON R. SMITH, M.D., C. ANNE SPENCER, B.Sc.,
DAVID E. JOHNSTONE, M.D., LUCILLE D. LALONDE, M.D., RICARDO M. BESSOUDO, M.D.,
MARTIN J. GARDNER, M.D., ROBERT N. ANDERSON, M.D.,
AND B. MILAN HORACEK, PH. D.
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SUMMARY To determine the depolarization and repolarization time-integral patterns in patients with
first acute inferior myocardial infarction, we acquired body surface potential maps in 28 men and eight
women, ages 36-76 years, a mean of 76 hours after the onset of symptoms. Based on technetium-99m
pyrophosphate myocardial scans, patients were divided into two groups. Group 1 included 22 patients with
scintigraphic activity limited to the left ventricle who were considered to have exclusive left ventricular
infarction, and group 2 included 14 patients with scintigraphic activity involving the right ventricle in
addition to the left ventricle, considered to have both left and right ventricular infarction.
Isointegral plots of the first 50% of the QRS complex (Q zone) were characterized by negative areas over
the inferior torso with concomitant extension of positive areas to the superior precordium. Group 2 patients
had greater leftward and superior extension of the negative inferior distributions than group 1 patients.
Subtraction of the mean Q-zone map of group 1 patients from that of group 2 patients confirmed a mean
area of difference over the right anterior-inferior torso. The average Q-zone integral value within this area
of difference was 5.9 + 7.2 ,uV*sec (±+ SD) for group 1 patients compared with 1.7 + 5.2 ,V-sec for group 2
patients (p < 0.05). ST-segment isointegral maps revealed positive inferior distributions in all subjects;
however, 29 patients also had abnormal negative ST-segment distributions over the precordium. The area
of negative precordial values in group 2 patients extended further rightward and inferiorly compared with
group 1 patients. There were two large areas of difference seen on subtraction: one over the precordium, in
which the mean ST-segment integral value for group 1 patients was -0.6 + 3.8 AV-sec, compared with
--3.2 3.2 tkVNsec for group 2 patients (p < 0.025), and another over the inferior torso, where the mean
value for group 1 was 1.2 ± 1.6 ,uV-sec, compared with 3.3 ± 3.5 ,xV sec for group 2 (p < 0.05).
Thus, in acute inferior infarction, there is a characteristic distribution of negative Q-zone and positive
ST-segment time integrals over the inferior torso and a reciprocal development of positive Q-zone and
negative ST-segment integrals over the anterior-superior torso. Patients with right ventricular involvement, however, have spatial and quantitative abnormalities of both depolarization and repolarization that
distinguish them from patients with infarction limited to the left ventricle.
THE INCREASED information content of body surface potential maps (BSPM) over standard electrocardiographic techniques offers promise that such maps
may be useful in assessing patients with myocardial
infarction. 14 To facilitate efficient management of the
mass of acquired data with BSPM, we have adopted
techniques based on the measurement of various time
integrals from each of multiple body surface ECG signals, with display in the form of isointegral contour
maps.5' This approach, while providing effective
data reduction, also retains much of the spatial information available from the more detailed instant-byinstant analysis of body surface potential maps. In
addition, time-integral analysis techniques offer a con-
venient means of detecting abnormal portions of the PQRS-T complex that require more detailed assessment.
In this study of patients with acute inferior infarction, we used isointegral analysis techniques to define
the body surface distributions of early depolarization
(Q-zone) and repolarization (ST-segment) time integrals. We also attempted to determine if the addition of
right ventricular infarction, as compared to exclusive
left ventricular involvement, has a significant influence on map appearances.
From the Departments of Medicine and Physiology and Biophysics,
Dalhousie University and Victoria General Hospital, Halifax, Nova
Scotia, Canada.
Supported by grants from the Nova Scotia Heart Foundation and the
Medical Research Council of Canada (SDG-2 and PG-18).
Dr. Smith's present address: Head, Cardiology Division, University
of Calgary, Calgary, Alberta, Canada T2N 1N4.
Address for correspondence: T.J. Montague, M.D., Room 305, Pavilion, Department of Medicine (Cardiology), Victoria General Hospital, Halifax, Nova Scotia, Canada B3H 2Y9.
Received May 27, 1982; revision accepted September 23, 1982.
Circulation 67, No. 3, 1983.
Patients with Myocardial Infarction
,-
Subjects and Methods
All subjects gave informed consent before the study.
From a consecutive series of 51 patients admitted to
the coronary care unit of the Victoria General Hospital
over an 11-month period with an initial diagnosis of
first acute inferior myocardial infarction, 36 patients
fulfilled all of the following criteria and were selected
as the study group. Twenty-eight were men and eight
were women, ages 36-76 years. All had a history of
ischemic-type cardiac pain compatible with a myocardial infarction; diagnostic cardiac enzyme elevations;
665
VOL 67, No 3, MARCH 1983
CIRCULATION
666
all study subjects had 2 + or greater focal scintigraphic
activity in the region of the inferior-posterior left ventricular myocardium. Using the classification of
Sharpe et al.,'3 scintigraphic evidence of additional
right ventricular infarction was considered present
when, in the LAO view, 2 + or greater activity extended from the region of the heart toward the sternum,
anterior to the interventricular septum. Final interpretation of myocardial images in this study represented
the consensus of two observers.
Based on the results of the scintigraphic scans in the
LAO view, the patients were divided into two groups.
Group 1 included 22 patients with scintigraphic activity limited to the left ventricle, considered to have
exclusive left ventricular infarction; and group 2 included 14 patients with scintigraphic activity involving
the right ventricle as well as the left ventricle, considered to have both right and left ventricular infarction.
abnormal Q waves in at least two of leads II, III and
aVF; presence of abnormal (2 + or greater, focal) scintigraphic activity involving the inferior-posterior left
ventricular wall on technetium-99m pyrophosphate
myocardial scans done within the first 72 hours of
admission; a clinical status of Killip class I or II at the
time of BSPM recordings; and absence of bundle
branch block.
Normal Control Subjects
A control group of 51 clinically normal subjects, 40
and 11 women, ages 20-46 years, was also recruited. None of these control subjects had a history of
cardiac disease and all had normal physical and echocardiographic examinations and 12-lead ECG tracings.
men
Nuclear Imaging
After injection of technetium-99m pyrophosphate,
images were obtained with a mobile Ohio Nuclear camera equipped with a low-energy, high-resolution, parallel-hole collimator. Images were obtained in
the anterior, 45°left anterior oblique (LAO) and left
lateral views to a total of 300,000 counts per image.
Unprocessed analog images were interpreted by two
independent observers blinded to other investigational
results. The degree of radionuclide uptake in the myocardium was assessed according to the classification of
Berman et al.'2 In this system, the designation of 4 +
= activity in the region of the myocardium greater
than that of bone; 3 + = activity equal to bone; 2 + =
activity less than bone; 1 + = slight activity; and 0 =
no detectable activity. In addition, 2 + or greater activity was classified as focal or diffuse. As noted above,
analog
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BSPM Recording
Our system of recording body surface ECG signals
has been described." Briefly, digitized ECG signals
are recorded simultaneously from 117 torso and three
limb leads using Wilson's central terminal as reference, at a sampling rate of 500 samples/sec/channel.
Each channel amplifier has a gain of 2000. With 10-bit
samples, resolution is 10 ,V for the least significant
bit in the dynamic range of + 5 mV.
BSPM Processing
The ECG signals
are processed off line on a Xerox
Sigma 5 general-purpose computer." Selective averaging of 15 continuous seconds of recorded P-QRS-T
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FIGURE 1. The averaged ECG signals recordedfrom 120 lead sites of a normal subject. The data are presented
in analog format. The exact anatomic placement of the torso leads (0-116) is illustrated in figure 3. Briefly, the
leads on the left of this figure represent the anterior torso and the leads on the right, the back. The column with
leads 25-32 is placed over the midsternum, with lead 25 approximately over the larynx and lead 32 below the
diaphragm. The column with leads 95-102 is placed over the dorsal spine, with lead 95 at approximately the C7
level. Leads 117-119 are recordedfrom limb sites, butfor illustrative purposes are shown here superimposed on
the left shoulder region.
BODY SURFACE ECG MAPPING OF INFERIOR MIlMontague et al.
FRRNK
667
All measurements of the various ECG time integrals
X*YJZ
are made from the averaged complexes at time instants
fIRI
Io
44
_-.
{,_
I4
fST-T
fsT
i..
determined from edited Frank X, Y and Z leads (fig.
2). Five time integrals were evaluated. The QRS time
integral was calculated for each lead as the algebraic
sum of all potentials from the time instant of QRS
onset to QRS offset, multiplied by the sampling interval. This represents the net area under the curve, with
the baseline as zero potential. The ST-T time integral
was similarly calculated from the time instant of QRS
offset to T offset; the QRST time integral represented
the algebraic sum of the QRS and ST-T time integrals.
The Q-zone time integral was calculated from the QRS
onset to the midpoint of the QRS complex and the ST
segment from the first three-eighths of the ST-T segment. Time integral units were expressed in ,uVsec.
For the purpose of this study, involving patients with
acute myocardial infarction, analysis was concentrated
on the Q-zone and ST-segment time integrals.
Downloaded from http://circ.ahajournals.org/ by guest on June 18, 2017
BSPM Display
FIGURE 2. (top) The superimposed Frank X, Y and Z leads
from a normal subject. The vertical lines represent the computer-identified time instants used for the various ECG time-integral measurements at all lead sites. (bottom) The signal from
one precordial lead of the same subject. The various time integrals evaluated are indicated by the horizontal arrows; the Qzone and ST-segment time integrals are further outlined by
diagonal lines and stippling, respectively. See text for details.
complexes is performed at each lead site; artifacts and
ectopic beats are rejected and the averaged complex is
placed with PR as baseline (fig, 1). Individual leads
are visually edited for wave-forrn appearance and
baseline drift. Invalid leads are rejected. For this study
of subjects at rest and with relatively low heart rates
(mean 69 beats/min), baseline drift was not a major
problem and only selective editing was required.
The display format for individual and group-mean
maps is illustrated in relation to torso and standard
chest electrode sites in figure 3. The rectangular area
represents the torso with both left and right margins
representing the right midaxillary line. The left half of
the map, therefore, represents the anterior torso and
the right half, the back. Each contour line within the
rectangle connects points of equal time-integral value.
The solid contour lines represent positive values and
the interrupted contour lines, negative values. The
contour lines progress logarithmically from the zone of
near-zero integral value with each decade line, as well
as the maximum and minimum, numerically identified. The torso electrodes are represented by dots; the
12-lead ECG V -V6 electrode positions, by squares.
The subtraction, or difference, maps were also displayed in logarithmic isointegral contour format. The
solid lines in these maps, however, represent areas in
which one study group had relatively greater integral
values compared with the other group. Interrupted
lines in intergroup difference maps represent areas
where one group had relatively lower integral values
compared with the other group.
FIGURE 3. Q-zone isointegral body surface
map from a normal subject. The rectangular
area represents the torso with both the left and
right margins representing the right mid-axillary line. The left half of the map represents the
anterior torso and the right half, the back. For
reference purposes, the location of each torso
electrode is represented by a dot and the Vj-V6
standard electrode positions are indicated by
small squares. All electrode columns are located according to previously defined anatomic landmarks.]]
668
CIRCULATION
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Study Protocol
All BSPMs were recorded in the coronary care unit
with the subjects in the supine position. At the time of
recording, all control and study subjects were in sinus
rhythm.
Individual time-integral maps, including Q-zone,
QRS, ST-T, ST segment and QRST, were plotted for
all subjects. Group-mean maps were also constructed
using the respective mean values at each lead site. To
further characterize differences between patients with
exclusive left ventricular involvement and those with
additional right ventricular involvement, the group 1
mean Q-zone and ST-segment time-integral maps
were subtracted from the corresponding group 2 mean
maps. The resulting subtraction, or difference, maps
spatially localized the mean Q-zone and ST-segment
areas of difference between the two patient groups.
These mean areas of difference identified by the subtraction process also served as areas of interest for
individual subjects, with the average value of the Qzone and ST-segment time integrals within these areas
being calculated for each patient in each group.
Intergroup comparisons of Q-zone and ST-segment
area of difference values were by t test for unpaired
observations.
Results
Figure 4 is a comparison of the mean Q-zone, QRS,
ST-T, ST-segment and QRST isointegral maps for the
36 inferior infarction patients and the corresponding
mean maps constructed from the control sample of 51
normal adult subjects. Both normal and patient groups
had similar sex distributions. Compared with normal
subjects, patients with inferior infarction demonstrated
negative Q-zone areas over much of the inferior torso
and extension of positive Q-zone areas to the superior
chest. Although there was some individual variation,
all patients with acute inferior infarction displayed
areas of negative Q-zone values over the inferior torso
(fig. 5). The inferior torso negativity displayed by the
early depolarization time integral (Q zone) was also
reflected in the QRS integral maps, although there was
greater individual variability in QRS distributions
compared to Q-zone plots. Similarly, ST-T plots
showed greater individual variability than ST-segment
distributions. ST-segment integral distributions in the
infarction patients tended to be positive inferiorly and
negative anteriorly -29 of the 36 patients had areas of
negative precordial ST-segment distributions. QRST
maps showed wide variation among individual patients; however, only five patients had non-dipolar distributions. Over the inferior torso, there was a relative
concordance of the areas of negative Q-zone and positive ST-segment distributions (fig. 4). A similar relative concordance was observed anteriorly between
areas of increased Q-zone positivity and ST-segment
negativity.
Representative individual and group-mean Q-zone
and ST-segment time-integral distributions of group 1
patients are compared to those of group 2 patients in
figures 5 and 6. The spatial distributions of Q-zone
VOL 67, No 3, MARCH 1983
integrals were similar in the two groups, probably reflecting the dominance of the left ventricular injury;
however, patients in group 2 tended to have a greater
area of negative Q-zone distribution over the right anterior-inferior chest. Groups 1 and 2 also had similar
ST-segment distributions, but group 2 patients tended
to have greater inferior and rightward extension of
negative anterior distributions and more superior extension of inferior positive patterns, particularly over
the right chest.
Using as criteria of right ventricular infarction a Qzone map pattern similar to the mean plot illustrated in
figure 6, blinded, retrospective analysis of individual
Q-zone maps of all infarction patients revealed a positive predictive value for the presence of right ventricular infarction of 69% and a negative predictive value of
78% (overall predictive accuracy 75%). Similar retrospective analysis of all individual ST-segment isointegral maps, using the spatial pattern of the group 2 mean
maps as the criteria of right ventricular involvement,
gave a positive predictive value of 35%.
The Q-zone isointegral difference map is illustrated
in figure 7. As might be expected from comparison of
the group-mean Q-zone maps (fig. 6), the major Qzone area of difference between the patient groups was
located over the anterior-inferior torso. In this area, the
average Q-zone value of group 2 patients was significantly (p < 0.05) less (mean 1.7 + 5.2 [ ± SD] /Vsec) than that in group I patients (5.9 + 7.2 /xV*sec);
that is, in this area, group 2 patients had more negative
Q waves or less positive R waves than group 1 patients. In the small area of difference located over the
precordium, both groups had similar integral values
(12.8 + 4.7 gV*secforgroup 1 patients vs 13.7 + 5.1
gV*sec for group 2 patients, NS).
The ST-segment time integral difference map (fig.
8) demonstrates a precordial area of difference in
which the group 2 patients had significantly (p <
0.025) more negative values (-3.2 + 3.2 pkV*sec)
than group 1 patients (-0.6 ± 3.8 JVosec). In the
area of difference over the right inferior chest, group 2
patients had significantly (p < 0.05) more positive
ST-segment integral distributions (3.3 ± 3.5 xV.sec)
than group 1 patients (1.2 ± 1.6 ,uV*sec).
Differences in Q-zone and ST-segment distribution
can also be appreciated by comparing a representative
120-lead ECG plot of a patient with exclusive left
ventricular infarction to that of a similar plot from a
patient with additional right ventricular involvement,
as shown in figure 9. These plots are from the same
patients illustrated in figure 5. In particular, the patient
with right ventricular involvement (fig. 9B) demonstrates a relatively greater area of negative Q zones
(deeper, more negative Q waves) in the right anteriorinferior leads, while the patient with exclusive left
ventricular infarction (fig. 9A) shows more positive
ST segments in the inferior leads.
Discussion
The increased information available with BSPM
suggests that it may be valuable in the assessment of
BODY SURFACE ECG MAPPING OF INFERIOR MIlMontague et al.
NORMAL
669
INFERIOR INFARCTION
QRS
ST-T
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QRST
.-10
I,
:
--
-----------
ST
ZONE
+30
FIGURE 4. Mean isointegral Q-zone, QRS, ST-T, ST-segment and QRST plots from 51 normal control subjects
and 36 study subjects with inferior infarction. These maps were constructedfrom the respective group-mean timeintegral values at each electrode site. All maps use the display format illustrated infigure 3 and described in the
text. In contrast to normal subjects, patients with inferior infarction had negative Q-zone areas over much of the
inferior torso with extension of positive Q-zone integrals to the superior torso. Conversely, the ST-segment
isointegral map in acute inferior infarction was characterized by abnormally positive inferior distributions and
concomitant negative precordial distributions.
patients with acute myocardial infarction. 1-8 Flowers et
al.,2 using serial isopotential maps, studied 22 patients
2-4 weeks after inferior-posterior myocardial infarction and noted large zones of QRS positivity over the
left anterior superior chest and areas of QRS negativity
over the lower chest, distributions not appreciated by
conventional ECG methods. In a study of 84 patients
with old myocardial infarction, Vincent and co-work-
ersI also noted an increased ability of the body surface
map to diagnose remote inferior myocardial infarction.
Others who have specifically studied repolarization
patterns in acute myocardial infarction have stressed
the increased sensitivity and desirability of total body
surface mapping techniques compared with conventional ECGs, or partial torso maps, for the assessment
of infarct size.6- In a previous study, we found isointe-
VOL 67, No 3, MARCH 1983
CIRCULATION
670
LV AND RV
INFARCTION
EXCLUSIVE LV
INFARCTION
;,
ZONE
"
I,
-12
-
',
--
,
I
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-20
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.
*_9
ST
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FIGURE 5. Q-zone and ST-segment isointegral plots, from a patient with exclusive left ventricular (LV) infarction (left) and a patient with biventricular involvement (right). Note the resemblance of these representative
individual Q-zone and ST-segment maps to the group-mean Q-zone and ST-segment maps illustrated in figure 6.
gral BSPM analysis useful in monitoring depolarization and repolarization changes during the early evolution of acute myocardial infarction.5 The results of the
present study extend our application of BSPM techniques in the setting of acute myocardial infarction.
In this study, using isointegral techniques, we found
that patients with acute inferior infarction have a zone
of negative Q-zone distribution over the inferior torso
with increase in positivity over the anterior-superior
torso. ST-segment distributions were characterized by
negative inferior torso positivity and anterior torso
negativity. These concomitant, but vectorally opposite, depolarization and repolarization time-integral
torso patterns were observed in most of our patients.
Previous studies using conventional electrocardiographic techniques have also noted an opposing pattern
of anterior and inferior ST-segment distributions in
some patients with acute inferior myocardial infarc-
LV AND RV
INFARCTION
EXCLUSIVE LV
INFARCTION
+30
-
ZONE
;,
-
ST
5..-
-1.
-
*)
-X;E
f
+7
FIGURE 6. Comparison of the mean Q-zone and ST-segment isointegral plots from 22 patients with exclusive left
ventricular (LV) involvement and 14 patients with additional right ventricular (RV) involvement during acute
inferior myocardial infarction. Patients with RV involvement tended to have a greater area of negative Q zone
over the right anterior-inferior torso and greater inferior and rightward extension of negative anterior ST-segment
distributions.
BODY SURFACE ECG MAPPING OF INFERIOR MI/Montague et al.
Q -
ZONE AREAS - OF DIFFERENCE
-
10.'""
NEGATIVE AREA
RVI
LVI
30-
n=14 n=22
POSITIVE AREA
RVI
LVI
n = 14 n = 22
0
20-
S
0
0
0)
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Among our patients, the high prevalence of concomitant anterior torso ST-segment negativity and inferior
torso positivity, together with a similar high prevalence of anterior positive and inferior negative Q-zone
distributions, suggests that both patterns represent true
reciprocal electrocardiographic changes. These reciprocal effects in both depolarization and repolarization
are presumably due to the loss of balancing or canceling wave fronts consequent to the area of acute inferior
myocardial injury. However, some of the apparent
reciprocal anterior torso Q-zone and ST-segment
changes may also be due to coexistent anterior ischemia or anterior wall motion abnormalities. Further
studies correlating regional torso ECG distributions,
regional myocardial wall motion and underlying coronary anatomy are required.
Previous studies using abnormal elevation of STsegment distributions in right-sided precordial leads
suggest that the ECG can reflect right ventricular involvement in inferior myocardial infarction.22 24 More
recent studies have confirmed that early, transient ST-
ST AREAS - OF - DIFFERENCE
0
0)
0)
p
=
671
N.S.
--------------
FIGURE 7. Mean Q-zone difference map. This map was constructed by subtracting the mean Q-zone map of the patients
with exclusive left ventricular involvement (LVI)from the mean
Q-zone map of the group with additional right ventricular involvement (RVI). The mean areas of difference between the LVI
and RVI groups are spatially indicated by the isointegral contour lines. The solid lines (positive area) represent the torso
area where RVI patients had relatively greater Q-zone values
than the LVI patients; the interrupted lines (negative area)
represent the area where RVI patients had relatively lower Qzone values than the LVI group. The average Q-zone value
within these mean areas of difference was calculated for each
subject in the RVI and LVI groups and is displayed below the
map. In the spatially larger "negative" area of difference over
the right anterior-inferior torso, the Q-zone values of RVI patients were significantly (p < 0.05) less than that of the LVI
group. Within the spatially smaller "positive" area of difference, there was not, however, a significant difference in Q-zone
values between the patient groups.
tion, although the prevalence of this finding has usually been less than we observed. 14-9 The pathologic basis
and clinical significance of negative anterior ST-segment distributions in patients with acute inferior myocardial infarction is controversial. It has been attributed to "reciprocal" or strictly electrical effects of the
inferior wall damage,20 to coexisting anterior wall ischemia secondary to left anterior descending coronary
artery disease'8 and to posterolateral infarction. 14 Some
investigators have found the presence of anterior STsegment depression to be a predictor of more severe
left ventricular dysfunction;'4' 16, 19 othershave not.'5
NEGATIVE AREA
LVI
RVI
n = 14 n= 22
10-
POSITIVE AREA
RVI
LVI
n = 14 n= 22
0
6)
0
5-
0
I
0
0
soi
0)
Ca
zoo
0
0-
I
0))
0
0g&
5)
0
0))
0
-5-
*)
0
-10-
p<
S
0.025
p< 0.05
FIGURE 8. Mean ST-segment difference map and individual
patient's average ST-segment integral values for each area of
difference. The methods were the same as those in figure 7. In
the "positive" area of difference (solid lines), located over the
inferior torso, patients with right ventricular involvement (RVI)
had ST-segment values significantly greater (p < 0.05) than
those of the LVI patients; in the "negative" area of difference
(interrupted lines), located mostly over the precordium, patients with RVI had significantly (p < 0.025) lower ST-segment
values than patients with exclusive LVI.
672
CIRCULATION
VOL 67, No
A
3, MARCH 1983
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FIGURE 9. The averaged ECG signal, in analog format, at each of the 120 lead sites from a subject with
exclusive left ventricular infarction (A) and from a patient with additional right ventricular infarction (B). The
display format is the same as figure 1. Leads 19, 28 and 36 in map B have been edited, 19 and 28 because of an
obvious incorrect wave form and 36 because of incorrect positioning of baselinle. These plots are from the same
subjects whose Q-zone and ST-segment isointegral plots are illustrated in figure 5.
segment elevation in lead V4R is a sensitive and specif-
ic indicator of right ventricular involvement in inferior
myocardial infarction.25 26 tdoes appear critical, however, that V4R be recorded early in the course of infarction to retain its predictive value for right ventricular
involvement.25'26 Body surface isopotential maps have
also been used on an experimental basis for the diagnosis of right ventricular infarction in dogs.27 Canine
studies have revealed that dogs with exclusive right
ventricular infarction had, during the early and middle
stages of ventricular depolarization, negative distributions over the right anterior chest surface.26 Our data
reveal that there are differences in surface electrocardiographic patterns of early depolarization (Q-zone)
and early repolarization (ST-segment) time integrals
between patients with exclusive left ventricular involvement and patients with biventricular involvement
in acute inferior myocardial infarction. Although collectively a detectable effect of right ventricular infarction was evident on group-mean BSPMs, the predictive value of identifying any particular patient as
having right ventricular involvement, at least by retrospective BSPM pattern analysis, was only moderately
reliable (69% with Q-zone pattern recognition). At the
relatively late point in infarction evolution at which the
BSPMs were recorded in this study, the depolarization
time-integral (Q-zone) pattern was of more discriminative value, however, than assessment of the repolarization (ST-segment) pattern (positive predictive value of
35%). Further prospective studies are required to as-
BODY SURFACE ECG MAPPING OF INFERIOR MIVMontague et al.
sess whether Q-zone or ST-segment maps acquired
earlier in the evolution of inferior infarction would
allow better individual discrimination between patients
with exclusive left ventricular involvement and those
with additional right ventricular involvement.
In conclusion, body surface ECG maps provide
unique data in patients with myocardial infarction. In
particular, inferiorly located myocardial infarction or
injury is well reflected by BSPM patterns. Patients
with right ventricular involvement have spatial and
quantitative abnormalities of both depolarization and
repolarization time integrals that distinguish them
from patients with exclusive left ventricular involvement. Although the results of this study are preliminary, the ability of difference maps to locate areas of
interest for quantitative analysis offers promise that
application of this or related techniques may be of
value in the assessment of the size of myocardial injury
and its change with time or with interventions.
Downloaded from http://circ.ahajournals.org/ by guest on June 18, 2017
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Circulation. 1983;67:665-673
doi: 10.1161/01.CIR.67.3.665
Circulation is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231
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