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Electrocardiographic Differentiation of the Causes of Left Ventricular Diastolic Overload
Electrocardiographic Electrocardiographic Differentiation Differentiation of of the the Causes Causes of of Left Left Ventricular Ventricular Diastolic Diastolic Overload* Overload* Leo Schamroth, M.D., Cohn L. L. Schamroth, Leo Schamroth, M.D., F.C.C.P; EC.C.P'; Colin Schamroth, M.D.; M.D.; Pinhas Sareli, M.D.; and David Pinhas Sareli, M.D.; and David Hummel, Hummel, M.D. M.D.
Left ventricular hypertrophy due to diastoUc diastolic overload Left ventricular hypertrophy due to overload isis characterized by V6: (a) characterized by the the following following inin lead lead V,: (a) tall tall RR wave; wave; (b) (b) prominent initial Q Q wave; (c) minimally minimally elevated concaveprominent initial wave; (c) elevated concaveupward ST segment; segment; and (d) (d) relatively tall symmetrical symmetrical T upward ST and relatively tall T wave. Reciprocal S waves waves are are seen wave. Reciprocal deep deep S seen inin lead lead V1. VI' This This study reflects further evaluation of these these parameters study re8ects aa further evaluation of parameters inin
the four main of left ventricular diastolic overload: the four main causes causes of left ventricular diastoUc overload: mitral incompetence, patent mitral incompetence, incompetence, aortic aortic incompetence, patent ductus ductus arteriosus, septal defect. An S wave in lead arteriosus, and and ventricular ventricular septal defect. An S wave in lead V1 which is is equal to or the R R wave wave in in lead lead V, V6 VI which equal to or greater greater than than the excludes the diagnosis incompetence. excludes the diagnosis of of mitral mitral incompetence.
eft ventricular ventricular hypertrophy is classically repre~ft hypertrophy is classically repre-
(2) deep S wave wave in lead VI' V,. (2) AA deep S in lead
sented by S wave lead V, sented by aa deep deep S wave inin lead VI and and tall tall RR wave wave in lead When, for example, the sum sum of these in lead V6. Ve' When, fur example, the of these deflections exceeds 35 mm mm in adult, the diagnosis deflections exceeds 35 in the the adult, the diagnosis of left ventricular hypertrophy is made. made. In In 1956, of left ventricular hypertrophy is 1956, Cabrera and Monroy’ further attempted to differentidifferentiCabrera and Monroy' further attempted to ate the the electrocardiographic electrocardiographic manifestations of left left ate manifestations of ventricular hypertrophy the basis ventricular hypertrophy on on the basis ofof the the hemohemodynamic state. This heralded the overload dynamic state. This heralded the overload concept. concept. Left ventricular ventricular systolic overload occurs with ininLeft systolic overload occurs with during systole, as creased resistance toto contraction contraction during creased resistance systole, as would occur with systemic hypertension and aortic and aortic would occur with systemic hypertension stenosis. ItIt is is reflected electrocardiographically by stenosis. reflected electrocardiographically by the the following (illustrated in 1): fullowing (illustrated in diagram diagram CC ofof Fig Fig 1): (1) A tall R (1) A tall R wave wave inin lead lead V6. Ve. (2) A deep S wave wave in in lead lead V,. (2) A deep S VI' (3) A absent initial Q wave in (3) A small small or or absent initial Q wave in lead lead V6, Ve, probably probably the expression of an the expression of an associated associated incomplete incomplete left left bundle bundle branch branch block. block. (4) limbs and and aa (4) An An inverted inverted TT wave wave with with asymmetrical asymmetrical limbs relatively blunt nadir in in lead lead Ve. V6. relatively blunt nadir (5) and slightly slightly convex-upward (5) AA minimally minimally depressed depressed and convex-upward ST segment in lead V6. ST segment in lead Ve. Left is associated associated with Left ventricular ventricular diastolic diastolic overload overload is with increased distention and pressure during diastole. increased distention and pressure during diastole. ItIt occurs with increased filling of left ventricle ventricle in occurs with increased filling of the the left in conditions such as conditions such as aortic aortic incompetence, incompetence, mitral mitral incomincompetence, ventricular septal defect, and patent ductus patent ductus petence, ventricular septal defect, and arteriosus. Left ventricular ventricular diastolic overload is rearteriosus. Left diastolic overload is reflected electrocardiographically by the following (illusflected electrocardiographically by the fullowing (illustrated diagram B of of Fig Fig 1): 1): trated inin diagram B (1) A tall R wave in lead V6, frequently taller that (1) A tall R wave in lead Ve, frequently taller than than that which ventricular systolic overwhich occurs occurs with with left left ventricular systolic overload. load.
(3) relatively deep, initial Q Q wave (3) AA prominent, prominent, relatively deep, initial wave inin lead lead
‘From the the University the WitWit*From the Baragwanath Baragwanath Hospital Hospital and and the University of of the watersrand, Johannesburg, South Africa. watersrand, Johimnesburg, South Africa. Manuscript received March 13; revision accepted June 13; revision accepted June 7.7. Manuscript received March Reprint requests: Dr Hospital, P0 Reprint request8: Dr. Schamroth, Schamroth, Baragwanath Baragwanath Hospital, PO Bertsham, Bert8ham, Johannesburg, Johannesburg, South South Africa Africa 2013 2013
Ve·
V6.
(4) elevated, concave-upward ST segment segment (4) Minimally Minimally elevated, concave-upward ST in lead V6. lead Ve. (5) and symmetrical symmetrical TT wave in lead (5) Relatively Relatively tall tall and wave in lead V6. Ve. The study was The following fullowing study was undertaken undertaken toto evaluate evaluate the the further differentiation of left ventricular further differentiation ofleft ventricular diastolic diastolic overoverload hitherto undescribed sign: the magnitude of load by by aa hitherto undescribed sign: the magnitude of the This enables enables the separation of the SS wave wave inin lead lead V,. VI' This the separation of the the left incompeleft ventricular ventricular diastolic diastolic overload overload of of mitral mitral incompetence from that aortic incompetence, ventricular that of of aortic incompetence, ventricular tence from septal defect, and ductus arteriosus. septal defect, and patent patent ductus arteriosus. METHODS AND MATERIALS METHODS AND MATERIALS The material comprised 106 cases The material comprised 106 cases ofof left left ventricular ventricular diastolic diastolic overload which were collected consisting of 41 overload which were collected consecutively, consecutively, and and consisting of 41 cases incompetence, 32 cases aortic incompetence, 19 cases of of mitral mitral incompetence, 32 cases of of aortic incompetence, 19 cases arteriosus, and 14 14 cases of ventricular ventricular septal cases of of patent patent ductus ductus arteriosus, and cases of septal defect. The diagnosis confirmed as follows: defect. The diagnosis was was made made clinically clinically and and confirmed as follows: Of with mitral mitral incompetence, Of the the 41 41 cases cases with incompetence, 26 26 were were confirmed confirmed by by cardiac six by cardiac catheterization catheterization as as well well asas surgery, surgery, six by cardiac cardiac catheterizacatheterization and nine tion only, and nine by by surgery surgery only. only.
A. A.
B.
c.
V6
C.
FIGURE 1. Diagrams illustrating: A, in lead B, left FIGURE 1. Diagrams illustrating: A, normal normal ECC ECG in lead V6; Va; B,left ventricular diastolic overload; and C, C, left ventricular systolic overventricular diastolic overload; and left ventricular systolic overload. load.
CHEST / 89 89 11 Il 1 I JANUARY. JANUARY, 1986 CHEST 1 1988
95 95
Table Table 1-Means I-Meana and and Standard Standard Deviations Deviationa of of the the RR Wave Wave Amplitude Amplitude iniR Lead Lead V5, V" The The SS Wave Wave Amplitude Amplitude in in Lead Lead V,, V" and the the R:RS R:RS Ratios Ratio8 and
meaningless meaningless ififthe the SS wave wave isis 0,0, since since the the R:S R:S ratio ratio would would be be infinity, infinity,
and aa mean mean ofof the the ratios ratios cannot cannot then then be be expressed. expressed. and Using Using the the R:RS R:RS ratio, ratio, an an absent absent SS wave wave would would result result inin an an index index of of 1. All 1. All other other indices indices would would be be less less than than 1.1. An An Rwave R wave that that isis equal equal toto the the SS wave wave would would result result inin anan index index ofof 0.5. 0.5. An An RR wave wave greater greater than than the the SS wave 1. A wave would would result result inin an an index index between between 0.5 0.5 and and 1. A simple simple RR toto SS ratio ratio of 2:1 or 1. An or higher higher would would result result inin R:RS R:RS ratios ratios between between 0.66 0.66 and and 1. An RR of2:1 wave S wave veuld result less than than wave less less than than the the S wave would result inin anan R:RS R:RS ratio ratio of ofk,ss 0.5. 0.5.
RV, RYe N N
Diagnosis Diagnosis
SV SV, I
RV8 RY.
RV6+SV, RYe+SVI
Mitral 11.33±6.76 0.74±0.11 Mitral incompetence incompetence 41 41 30.43±8.18 3O.43±S.IS 1l.33±6.76 0.74±0.1l Aortic Aortic incompetence incompetence
32 32
28.17±9.51 24.94±8.70 28.17±9.51 24.94±S.70 0.53±0.09 0.53±0.09
19 19
IS.82±7.98 21.66±7.37 0.47±0.11 18.82±7.98 21.66±7.37 0.47±o.11
Patent ductus ductus Patent arteriosus arteriosus
STATISTICAL METHODS STATISTICAL METHODS The one way The data data were were analyzed analyzed by by means means of of aa one way analysis analysis of ofvariance. variance.
Ventricular septal septal Ventricular defect defect
14 14
This was followed This analysis analysis was fOllowed by by aa pairwise pairwise Student’s Students t-test t-test procedure procedure
1l.00±S.00 11.00±8.00 12.46±7.06 0.47±0.13 12.46±7.06 0.47±0.13
where the level was adapted according toto the the principles the test test level' was adapted according principles laid laid where down by Bonferroni3: of <0.0167 <0.0167 was achieve by Bonferro~3: aa pp value value of was required required toto achieve down the confidence level; p
Of the Of the 32 32 cases cases with with aortic aortic incompetence, incompetence, ten ten were were confirmed confirmed by by cardiac catheterization as well as as surgery, surgery, eight by cardiac cardiac cardiac catheterization as well eight by catheterization five by by surgery nine by by echocardiogracatheterization only, only, five surgery only, only, and and nine echocardiography. phy. Of Of the the 19 19 cases cases with with patent patent ductus ductus arteriosus, arteriosus, all all were were confirmed confirmed by of these were submitted fOr by cardiac cardiac catheterization, catheterization, and and 18 18 of these were submitted for surgical correction. surgical correction. Of with ventricular ventricular septal septal defect, defect, all confirmed Of the the 14 14 cases cases with all were were confirmed by cardiac catheterization, and were submitted fOr by cardiac catheterization, and 11 U of of these these were submitted for surgical correction. surgical correction. Cases with pulmonary hypertension were excluded from the Cases with pulmonary hypertension were excluded &om the study. study. The amplitudes amplitudes of the the S S wave wave in in lead lead VI V, and the R R wave wave in lead V. V6 The of and the in lead were measured and their their relationship expressed in the the fOrm form of of the the and relationship expressed in were measured fOllowing ratio: following ratio: RV6 RY.
RESULTS REsuLJ"S
The of the S wave in lead lead VI V1 and and the the R ft The amplitudes amplitudes of the S wave in wave in in lead lead V6 as the the R:RS R:RS ratios ratios are are depicted wave Va asas well well as depicted in 1. The pairwise comparisons in Table Thble 1. The pairwise comparisons between between the the means of these these variables for the four groups are of variables for the four groups are means depicted A graph graph reflecting the R:S relaThble 2.2. A reflecting the R:S reladepicted inin Table tionship is shown shown in Figure Figure 2. is in 2. tionship DIscUssIoN DISCUSSION This study clearly shows that the electrocarThis study clearly shows that the electrocardiographic presentation may differ in in all all the the four four cited cited diographic presentation may differ examples of left left ventricular ventricular diastolic overload with examples of diastolic overload with respect to: respect to: (1) The The amplitude amplitude of the the R R wave in lead lead Va V6 considered considered (1) of wave in in isolation. isolation. in (2) The The amplitude amplitude of the the S S wave wave in in lead lead VI V1 considered considered (2) of isolation. in isolation.
RV6 + S V, RYe+SVI be referred to of This This will will be referred to as as the the R:RS R:RS ratio ratio and and is is an an adaptation adaptation of the the ratio by et the in ratio developed developed by Cabrera Cabrera et all al’ to to express express the R R to to S S relationship relationship in lead VI' V,, Ie, le, lead RV, RYI RV,+ S V, I RYI+SV was because aa simple R becomes This ratio This ratio was devised devised because simple R to to S S ratio ratio becomes 50
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FIGURE 2. Graphic Graphic representation of the the relationship relationship FIGURE 2. representation of between between the the RR wave wave inin lead lead V6 V. and and the the SS wave wave inin lead lead V1 VI in the the cases cases of of left left ventricular ventricular diastolic overload. in diastolic overload.
ECG Differentiation
of Left Ventricular
Diastolic
Overload
(Schansroth
eta!)
iL
I
VI Vt
II
III III
AVR AVR
AVI. AVL
AVF AVF
V2 V2
V3 V3
V4 V4
Vs VS
V6 V6
i
- f
---r-l
---I
~
i
!
--+#-t--+---+'-t
I
11'--' -+fl---t--+--jI
~
'
---1-[ 1
~--\-~ -J. -j- j . -
FIGURE FIGURE
-
-
--r--.----j I ' I --, ___ ,, --4.-1---,
---c --,
-
-
3. 3. Electrocardiogram Electrocardiogram showing showing
the features features ofof left left ventricular ventricular diastolic diastolic the overload due to aortic incompetence.
overload
due
to aortic
incompetence.
(3) (3) The The relationship relationship ofof the ~e amplitude amplitude of of the the RR wave wave inin lead lead V6 Va toto the the SS wave wave inin lead lead V1. VI'
(Fig (Fig 22 and and 33 and and Table Table 1). 1). The The R:RS R:RS ratio ratio ofof mitral mitral incompetence incompetence was was signifisignifi-
The The RR Wave Wave inin Lead Lead V6 Vs
cantly cantly higher higher than than those those ofof aortic aortic incompetence incompetence (p
The The RR wave wave amplitude amplitude inin lead lead V6 Va ofof mitral mitral incompeincompe-
ventricular ventricular septal septal defect defect (p<0.001) (p
tence tence was was significantly significantly taller taller than than those those ofof patent patent ductus ductus arteriosus arteriosus (p<0.00l), (p
In In 33 33 ofof the the 41 41 cases cases ofof mitral mitral incompetence, incompetence, the the RR wave wave inin lead lead V6 Va was was two two oror more more times times greater greater than than the the
defect 001). The defect (p<0. (p
electrocardiographic electrocardiographic presentation presentation ofof mitral mitral incompeincompe-
SS wave wave inin lead lead V, VI (Fig (Fig 2). 2). An An example example ofof the the classic classic
of of patent patent ductus ductus arteriosus arteriosus (,p
tence tence isis illustrated illustrated inin Figure Figure 4.4. This This isis also alsQ evident evident
septal septal defect defect (p
from from Figure Figure 22 where where 33 33 ofof the the 41 41 cases cases ofof mitral mitral incompetence incompetence are are located located on on oror above above the the axis axis depictdepict-
lead lead V6 Va ofof patent patent ductus ductus arteriosus arteriosus was was significantly significantly taller taller than than that that ofof ventricular ventricular septal septal defect defect (p(p = 0.018). 0.018).
=
ing the 2:1 2:1 RS RS ratio. ratio. Indeed, Indeed, the the mean mean R:RS R:RS ratio ratio ofof ing the 0.74 0.74 isis significantly significantly higher higher (p
Lead V1 VI
The Wave in The SS Wave in Lead
figure figure which which isis equivalent equivalent toto aa simple simple R:S R:S ratio ratio ofof 2:1). 2:1).
The The amplitude amplitude ofof the the SS wave wave inin lead lead V1 VI ofof mitral mitral
incompetence incompetence was was very very significantly significantly less less than than those tho~e
ItIt isis also also evident evident that that no no case case ofof mitral mitral incompetence incompetence occurs occurs on on oror below below the the YY= XX axis. axis. This This indicates indicates that that
associated associated with with aortic aortic incompetence incompetence (p<0.001), (p
there there are are no no case case ofof mitral mitral incompetence incompetence where where the the SS wave wave inin lead lead V1 VI was was equal equal toto oror greater greater than than the the RR wave wave
=
defect (p
inin lead lead V6. Va. With With aortic aortic incompetence, incompetence, patent patent ductus ductus
with with the the largest largest SS waves waves inin lead lead V,VI (a(a mean mean ofof 24.94 24.94
arteriosus, arteriosus, and and ventricular ventricular septal septal defect, defect, however, however, the the
mm). mm). InIn ten ten ofof the the 32 32 cases, cases, the the SS wave wave inin lead lead V1 VI was was
cases cases were were almost almost equally equally distributed distributed on on either either side side ofof
larger larger than than the the ftR wave wave inin lead lead V6. Va. AA typical typical example example ofof the incomthe electrocardiographic electrocardiographic presentation presentation ofofaortic aorticincompetence petence isis illustrated illustrated inin Figure Figure 3.3. The The SS wave wave amplitude amplituqe inin lead lead V1 V I ofof aortic aortic incompeincompe-
Table Table 2-P 2-P Values Value.for for Comparison Compdrisora ofofthe the Diagnostic DiagfIostic Groups Gmu". with with Respect Bapect toto the the Amplitudes Amplitudea of ofthe the RB Wave Wave in in Lead Lead V6. V., the the SS Wave Wtwe inin Lead Lead V,.V" and and RV,, BV. toto RV6+SVJ BV.+SV,
&tio Ratio
tence tence was was significantly significantly greater greater than than that that ofofaa ventricular ventricular septal septal defect defect (p
-
The The RR toto SS Relationship Relationship The The most most important important differentiating differentiating feature feature for for sepaseparating rating mitral mitral incompetence incompetence from from the the other other causes causes ofof left left ventricular ventricular diastolic diastolic overload overload was was the the RR toto SS relationship. relationsh!p. Thus, Thus, inin mitral mitral incompetence, incompetence, the the RR wave wave inin lead lead V6 Va was was always always taller taller than than the the SS wave wave inin lead lead V1 VI
Diagnostic Diagnostic Comparison Comparison
.
RR Wave Wave Amplitude Amplitude SS Wave Wave Amplitude Amplitude inin V8 Va
inin V1 VI
RV6 RVa RV6+ SV, 1 RV8 +SV
NS NS
<0.001 <0.001
<0.001 <0.001
MI MI with with PDA PDA
<0.001 <0.001
<0.001 <0.001
<0.001 <0.001
MI with VSD MIwith VSD
<0.001 <0.001
NS NS
<0.001 <0.001
Al AI with with VSD VSD
<0.001 <0.001
<0.001 <0.001
NS NS
AIwithPDA AI with PDA PDA with VSD PDAwith VSD
<0.002 <0.002
NS NS
NS NS
<0.002 <0.002
<0.001 <0.001
NS NS
MI MI with with Al AI
CHEST 89 Ii1 CHEST I189
1 /1 JANUARY, JANUARY, 1986 1988
97 97
i
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:
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.
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r. -.-C--
• __ j
I
L-_
I
II
III III
AVR AVR
AVL AVL
VI
V2
V3 V3
V4 V4
VS V5
AVF AVF V6 V6
L_
I
-1-"
':11,
-,
.
J.
A-
the Ieatures features of left left ventricular ventricular diastolic the of diastolic incompetence. overload due to overload due to mitral mitral incompetence.
:'1 .,J
FIGuRE 4. Electrocardiogram Electrocardiogram showing FIGURE 4. showing
--r-
the Y Y = = X X axis, axis, eg, eg, 30 30 below below and 35 above in aortic aortic the and 35 above in incompetence (Fig 2). 2). Furthermore, Furthermore, only two two of of 32 32 incompetence (Fig only cases of aortic aortic incompetence were associated with cases of incompetence were associated with aa simple R:S ratio ratio greater greater than 2:1 2:1 (Fig (Fig 2). 2). simple R:S than Sensitivity, Specificity and Predictive Predictive Accuracy Sensitivity, Specificity and Accuracy The presence presence of an an R:S R:S ratio ratio of of 2:1 2:1 or or higher higher can be The of can be used to diagnose diagnose mitral incompetence with used to mitral incompetence with a sensitivity of of 75. 75.6 6 percent, specificity of 95.4 percent, and aa ity percent, aa specificity of95.4 percent, and predictive accuracy of 91. 91.2 2 percent. percent. The manifestation manifestation predictive accuracy of The of an an S S wave in lead lead VI V1 of of lesser lesser amplitude than the the R ft of wave in amplitude than wave in lead lead V6 can can be be used used to diagnose diagnose mitral wave in Ve to mitral incompetence with sensitivity of 100 percent, percent, incompetence with aa sensitivity of aa specificity of 49.2 49.2 percent and a a predictive predictive accuracy of specificity of percent and accuracy of 56.2 percent. percent. 56.2 100
Mechanisms Mechanisms The normal normal horizontal plane QRS axis axis is is directed directed to The horizontal plane QRS to
A. A.
the left and and slightly slightly posteriorly (as illustrated illustrated in diadiathe left posteriorly (as in gram A of 5). It It is thus usually usually directed to a a region region gram A of Fig Fig 5). is thus directed to midway between the V6 and VI V, lead lead axes. axes. The The impresimpresmidway between the V8 and sion on on these these leads leads ;s is consequently consequently about ie, the the sion about equal, equal, ie, ft wave wave in lead lead ‘6 is of of approximately approximately the same R in V8 is the same amplitude as the S S wave wave in in lead lead V,. must be in VI' ItIt must be borne borne in amplitude as the mind that the horizontal plane axes cannot be localized mind that the horizontal plane axes cannot be localized with the the same same accuracy accuracy or finesse finesse as the the frontal frontal plane with or as plane axes. This This is is due due to to the the variability variability which occurs with axes. which occurs with body build and electrode electrode placement, and which which are body build and placement, and are easily reflected reflected on the the proximity leads of the horizontal horizontal easily on proximity leads of the plane when when compared compared with the the relatively relatively remote leads plane with remote leads of the the frontal frontal plane. of plane. With left ventricular ventricular hypertrophy due to to systolic systolic With left hypertrophy due overload, the magnitude magnitude of the QRS vector is increased increased overload, the of the QRS vector is but the direction is usually maintained so that that the the but the direction is usually maintained so amplitude of the deep S wave wave in in lead lead VI V1 is approxamplitude of the deep S is approximately that of of the the tall tall R R wave wave in in lead lead V8 V6 (diagram (diagram A of of imately that A
B.
B.
------F------'--+~V&
-----I-IIIIIIII:::===:=L+~V.
,.+
,.+ V1
vi V1
FIGURE 5. Diagrams illustrating the horizontal horizontal plane QRS in: A, A, aortic aortic incompetence, incompetence, patent ductus FIGURE 5. Diagrams illustrating the plane QRS vector vector in: patent ductus
arteriosus, and ventricular ventricular septal defect; and B, B, mitral mitral incompetence. incompetence. arteriosus, and septal defect; aild
98 II
ECG DiIIIInIntIaIIo Differentiation of Left Left Ventrtcular Ventricular Diastolic CMrIoad Overload (SchamtDth (Schamroth et a!) ECG 01 DIIItoIIc et e/)
Fig Fig 5). 5). With With left left ventricular ventricular diastolic diastolic overload overload due due toto
consequently consequently result result inin larger larger deflections. deflections. This This
aortic aortic incompetence, incompetence, the the horizontal horizontal plane plane QRS QRS axis axis is is
hypothesis was previously previously put put fbrward forward by by Grant.4 Grant. 4 hypothesis was
similarly similarly directed directed and and increased increased inin magnitude. magnitude. ItIt is,is, CONCLUSIONS CONCLUSIONS
however, however, commonly commonly aa little little more more anteriorly anteriorly placed placed soso that, although both deflections are increased in that, although both deflections are increased in magnimagni-
If, If, inin left left ventricular ventricular diastolic diastolic overload, overload, the the ampliampli-
tude, the RRwave wave inin lead lead V6 Va isis often often slightly slightlygreater greater than than tude, the the the SS wave wave inin lead lead V1, Vb but but this this isis not not invariably invariably so. so. This This
tude tude ofofthe the SS wave wave inin lead lead V1 VI isis equal equal toto oror greater greater than than the R wave in lead V6, the diagnosis of mitral the R wave in lead Ve, the diagnosis of mitral incompeincompe-
occurred occurred inin 21 21 ofof the the 32 32 cases cases (Fig (Fig 2). 2).
tence 001). If, excluded (p
With With mitral mitral incompetence, incompetence, the the ftRwave wave inin lead lead V6 V6 was was
diastolic the ratio ratio ofofthe the RR wave wave inin lead lead V6 Ve toto diastolic overload, overload, the
always always larger larger than than the the SS wave wave inin lead lead V1, Vb and and usually usually
the the SS wave wave inin lead lead V1 VI isis 2:1 2:1 oror greater, greater, the the diagnosis diagnosis ofof
appreciably so. This This isis due due toto important important anterior anterior appreciably so.
mitral mitral incompetence incompetence isis most most likely likely (p
displacement the left left ventricle, ventricle, and and hence, hence, the the QRS QRS displacement ofofthe axis axis asas aa result result ofofthe the enlarged enlarged left left atrium atrium (diagram (diagram BB ofof Fig Fig 5). 5). When When this this occurs, occurs, the the horizontal horizontal plane plane QRS QRS
tence. leftventricular ventriculardiastolic diastolicoverload, overload,both boththethe tence. IfIf,ininleft RR wave large wave inin lead lead V6 Ve and and the the SS wave wave inin lead lead V1 VI are are ofoflarge
axis lead axis axis will will bebeclosely closely aligned aligned with with the the V6 Vslead axis and and will will
magnitude, magnitude, the the most most likely likely diagnosis diagnosis isis aortic aortic incomincom-
tend tend toto bebe perpendicular perpendicular toto the the lead lead V1 VI axis. axis. The The
petence. petence.
impression impression will will thus thus bebe far far greater greater on on the the V6 V6 lead lead axis axis than than on on the the V1 VI lead lead axis. axis. Furthermore, Furthermore, the the defiections deflections
ACKNOWLEDGMENT: ACKNOWLEDGMENT: We We are are indebted indebted toto Doctor Doctor S.S. G.G. Reinach Reinach for for the the statistical statistical analysis. analysis. This This study study was was supported supported byby aa grant grant from from the the South South African African Medical Medical Research Research Council. Councll.
will will bebe ofof large large amplitude amplitude inin lead lead V6 V6 for for the the following following reasons: reasons: (1) (1) There There isis left left ventricular ventricular hypertrophy. hypertrophy.
REFERENCES REFERENCES 11 Cabrera Cabrera CE, CE, Monroy Monroy JR. JR. Systolic Systolic and and diastolic diastolic loading loading ofof the the
J
heart. 1 heart. Am Am Heart Heart J 1952; 1952; 43:66 43:661
(2) (2) The The QRS QRS axis axis isis more more aligned aligned with with lead lead V6. Va. Hence, Hence,
22 Cabrera Cabrera E,E, Muniz Muniz M, M, Prates Prates Flores Flores A,A, yy Costa Costa RochaJ. Rocha J. Semiolgia Semiolgia
its greater on on this this lead. lead. Compare Compare the the its impression impression isis greater
yy electrogenisis electrogenisis del del complejo complejo QRS QRS enen V1. VJ' Prin Prin Cardiolo Cardiolo 1958; 1958;
impression on lead lead V6 V6 inin diagrams diagrams AA and and BB ofof impression on Figure Figure 5.5. (3) (3) The The anterior anterior displacement displacement will will cause cause the the ventricle ventricle toto be be closer closer toto the the precordial precordial electrodes electrodes which which will will
5:335 5:335 33 Neter Neter J,J, Wasserman Wasserman W. W. Applied Applied linear linear statistical statistical models. models. HomeHomewood, wood, IL: IL: Richard Richard DD Irwin Irwin Inc. Inc, 1974:730 1974:730 44 Grant Grant RE RP. Clinical Clinical electrocardiography. electrocardiography. New New York: York: The The Blakiston Blakiston Division, Division, McGraw-Hill McGraw-Hill Book Book Co, Co, mc, Inc, 1957:75 1957:75
CHEST CHEST II 8989 IlI
1 II JANUARY, JANUARY, 1986 1888
99 81
Left ventricular hypertrophy due to diastoUc diastolic overload Left ventricular hypertrophy due to overload isis characterized by V6: (a) characterized by the the following following inin lead lead V,: (a) tall tall RR wave; wave; (b) (b) prominent initial Q Q wave; (c) minimally minimally elevated concaveprominent initial wave; (c) elevated concaveupward ST segment; segment; and (d) (d) relatively tall symmetrical symmetrical T upward ST and relatively tall T wave. Reciprocal S waves waves are are seen wave. Reciprocal deep deep S seen inin lead lead V1. VI' This This study reflects further evaluation of these these parameters study re8ects aa further evaluation of parameters inin
the four main of left ventricular diastolic overload: the four main causes causes of left ventricular diastoUc overload: mitral incompetence, patent mitral incompetence, incompetence, aortic aortic incompetence, patent ductus ductus arteriosus, septal defect. An S wave in lead arteriosus, and and ventricular ventricular septal defect. An S wave in lead V1 which is is equal to or the R R wave wave in in lead lead V, V6 VI which equal to or greater greater than than the excludes the diagnosis incompetence. excludes the diagnosis of of mitral mitral incompetence.
eft ventricular ventricular hypertrophy is classically repre~ft hypertrophy is classically repre-
(2) deep S wave wave in lead VI' V,. (2) AA deep S in lead
sented by S wave lead V, sented by aa deep deep S wave inin lead VI and and tall tall RR wave wave in lead When, for example, the sum sum of these in lead V6. Ve' When, fur example, the of these deflections exceeds 35 mm mm in adult, the diagnosis deflections exceeds 35 in the the adult, the diagnosis of left ventricular hypertrophy is made. made. In In 1956, of left ventricular hypertrophy is 1956, Cabrera and Monroy’ further attempted to differentidifferentiCabrera and Monroy' further attempted to ate the the electrocardiographic electrocardiographic manifestations of left left ate manifestations of ventricular hypertrophy the basis ventricular hypertrophy on on the basis ofof the the hemohemodynamic state. This heralded the overload dynamic state. This heralded the overload concept. concept. Left ventricular ventricular systolic overload occurs with ininLeft systolic overload occurs with during systole, as creased resistance toto contraction contraction during creased resistance systole, as would occur with systemic hypertension and aortic and aortic would occur with systemic hypertension stenosis. ItIt is is reflected electrocardiographically by stenosis. reflected electrocardiographically by the the following (illustrated in 1): fullowing (illustrated in diagram diagram CC ofof Fig Fig 1): (1) A tall R (1) A tall R wave wave inin lead lead V6. Ve. (2) A deep S wave wave in in lead lead V,. (2) A deep S VI' (3) A absent initial Q wave in (3) A small small or or absent initial Q wave in lead lead V6, Ve, probably probably the expression of an the expression of an associated associated incomplete incomplete left left bundle bundle branch branch block. block. (4) limbs and and aa (4) An An inverted inverted TT wave wave with with asymmetrical asymmetrical limbs relatively blunt nadir in in lead lead Ve. V6. relatively blunt nadir (5) and slightly slightly convex-upward (5) AA minimally minimally depressed depressed and convex-upward ST segment in lead V6. ST segment in lead Ve. Left is associated associated with Left ventricular ventricular diastolic diastolic overload overload is with increased distention and pressure during diastole. increased distention and pressure during diastole. ItIt occurs with increased filling of left ventricle ventricle in occurs with increased filling of the the left in conditions such as conditions such as aortic aortic incompetence, incompetence, mitral mitral incomincompetence, ventricular septal defect, and patent ductus patent ductus petence, ventricular septal defect, and arteriosus. Left ventricular ventricular diastolic overload is rearteriosus. Left diastolic overload is reflected electrocardiographically by the following (illusflected electrocardiographically by the fullowing (illustrated diagram B of of Fig Fig 1): 1): trated inin diagram B (1) A tall R wave in lead V6, frequently taller that (1) A tall R wave in lead Ve, frequently taller than than that which ventricular systolic overwhich occurs occurs with with left left ventricular systolic overload. load.
(3) relatively deep, initial Q Q wave (3) AA prominent, prominent, relatively deep, initial wave inin lead lead
‘From the the University the WitWit*From the Baragwanath Baragwanath Hospital Hospital and and the University of of the watersrand, Johannesburg, South Africa. watersrand, Johimnesburg, South Africa. Manuscript received March 13; revision accepted June 13; revision accepted June 7.7. Manuscript received March Reprint requests: Dr Hospital, P0 Reprint request8: Dr. Schamroth, Schamroth, Baragwanath Baragwanath Hospital, PO Bertsham, Bert8ham, Johannesburg, Johannesburg, South South Africa Africa 2013 2013
Ve·
V6.
(4) elevated, concave-upward ST segment segment (4) Minimally Minimally elevated, concave-upward ST in lead V6. lead Ve. (5) and symmetrical symmetrical TT wave in lead (5) Relatively Relatively tall tall and wave in lead V6. Ve. The study was The following fullowing study was undertaken undertaken toto evaluate evaluate the the further differentiation of left ventricular further differentiation ofleft ventricular diastolic diastolic overoverload hitherto undescribed sign: the magnitude of load by by aa hitherto undescribed sign: the magnitude of the This enables enables the separation of the SS wave wave inin lead lead V,. VI' This the separation of the the left incompeleft ventricular ventricular diastolic diastolic overload overload of of mitral mitral incompetence from that aortic incompetence, ventricular that of of aortic incompetence, ventricular tence from septal defect, and ductus arteriosus. septal defect, and patent patent ductus arteriosus. METHODS AND MATERIALS METHODS AND MATERIALS The material comprised 106 cases The material comprised 106 cases ofof left left ventricular ventricular diastolic diastolic overload which were collected consisting of 41 overload which were collected consecutively, consecutively, and and consisting of 41 cases incompetence, 32 cases aortic incompetence, 19 cases of of mitral mitral incompetence, 32 cases of of aortic incompetence, 19 cases arteriosus, and 14 14 cases of ventricular ventricular septal cases of of patent patent ductus ductus arteriosus, and cases of septal defect. The diagnosis confirmed as follows: defect. The diagnosis was was made made clinically clinically and and confirmed as follows: Of with mitral mitral incompetence, Of the the 41 41 cases cases with incompetence, 26 26 were were confirmed confirmed by by cardiac six by cardiac catheterization catheterization as as well well asas surgery, surgery, six by cardiac cardiac catheterizacatheterization and nine tion only, and nine by by surgery surgery only. only.
A. A.
B.
c.
V6
C.
FIGURE 1. Diagrams illustrating: A, in lead B, left FIGURE 1. Diagrams illustrating: A, normal normal ECC ECG in lead V6; Va; B,left ventricular diastolic overload; and C, C, left ventricular systolic overventricular diastolic overload; and left ventricular systolic overload. load.
CHEST / 89 89 11 Il 1 I JANUARY. JANUARY, 1986 CHEST 1 1988
95 95
Table Table 1-Means I-Meana and and Standard Standard Deviations Deviationa of of the the RR Wave Wave Amplitude Amplitude iniR Lead Lead V5, V" The The SS Wave Wave Amplitude Amplitude in in Lead Lead V,, V" and the the R:RS R:RS Ratios Ratio8 and
meaningless meaningless ififthe the SS wave wave isis 0,0, since since the the R:S R:S ratio ratio would would be be infinity, infinity,
and aa mean mean ofof the the ratios ratios cannot cannot then then be be expressed. expressed. and Using Using the the R:RS R:RS ratio, ratio, an an absent absent SS wave wave would would result result inin an an index index of of 1. All 1. All other other indices indices would would be be less less than than 1.1. An An Rwave R wave that that isis equal equal toto the the SS wave wave would would result result inin anan index index ofof 0.5. 0.5. An An RR wave wave greater greater than than the the SS wave 1. A wave would would result result inin an an index index between between 0.5 0.5 and and 1. A simple simple RR toto SS ratio ratio of 2:1 or 1. An or higher higher would would result result inin R:RS R:RS ratios ratios between between 0.66 0.66 and and 1. An RR of2:1 wave S wave veuld result less than than wave less less than than the the S wave would result inin anan R:RS R:RS ratio ratio of ofk,ss 0.5. 0.5.
RV, RYe N N
Diagnosis Diagnosis
SV SV, I
RV8 RY.
RV6+SV, RYe+SVI
Mitral 11.33±6.76 0.74±0.11 Mitral incompetence incompetence 41 41 30.43±8.18 3O.43±S.IS 1l.33±6.76 0.74±0.1l Aortic Aortic incompetence incompetence
32 32
28.17±9.51 24.94±8.70 28.17±9.51 24.94±S.70 0.53±0.09 0.53±0.09
19 19
IS.82±7.98 21.66±7.37 0.47±0.11 18.82±7.98 21.66±7.37 0.47±o.11
Patent ductus ductus Patent arteriosus arteriosus
STATISTICAL METHODS STATISTICAL METHODS The one way The data data were were analyzed analyzed by by means means of of aa one way analysis analysis of ofvariance. variance.
Ventricular septal septal Ventricular defect defect
14 14
This was followed This analysis analysis was fOllowed by by aa pairwise pairwise Student’s Students t-test t-test procedure procedure
1l.00±S.00 11.00±8.00 12.46±7.06 0.47±0.13 12.46±7.06 0.47±0.13
where the level was adapted according toto the the principles the test test level' was adapted according principles laid laid where down by Bonferroni3: of <0.0167 <0.0167 was achieve by Bonferro~3: aa pp value value of was required required toto achieve down the confidence level; p
Of the Of the 32 32 cases cases with with aortic aortic incompetence, incompetence, ten ten were were confirmed confirmed by by cardiac catheterization as well as as surgery, surgery, eight by cardiac cardiac cardiac catheterization as well eight by catheterization five by by surgery nine by by echocardiogracatheterization only, only, five surgery only, only, and and nine echocardiography. phy. Of Of the the 19 19 cases cases with with patent patent ductus ductus arteriosus, arteriosus, all all were were confirmed confirmed by of these were submitted fOr by cardiac cardiac catheterization, catheterization, and and 18 18 of these were submitted for surgical correction. surgical correction. Of with ventricular ventricular septal septal defect, defect, all confirmed Of the the 14 14 cases cases with all were were confirmed by cardiac catheterization, and were submitted fOr by cardiac catheterization, and 11 U of of these these were submitted for surgical correction. surgical correction. Cases with pulmonary hypertension were excluded from the Cases with pulmonary hypertension were excluded &om the study. study. The amplitudes amplitudes of the the S S wave wave in in lead lead VI V, and the R R wave wave in lead V. V6 The of and the in lead were measured and their their relationship expressed in the the fOrm form of of the the and relationship expressed in were measured fOllowing ratio: following ratio: RV6 RY.
RESULTS REsuLJ"S
The of the S wave in lead lead VI V1 and and the the R ft The amplitudes amplitudes of the S wave in wave in in lead lead V6 as the the R:RS R:RS ratios ratios are are depicted wave Va asas well well as depicted in 1. The pairwise comparisons in Table Thble 1. The pairwise comparisons between between the the means of these these variables for the four groups are of variables for the four groups are means depicted A graph graph reflecting the R:S relaThble 2.2. A reflecting the R:S reladepicted inin Table tionship is shown shown in Figure Figure 2. is in 2. tionship DIscUssIoN DISCUSSION This study clearly shows that the electrocarThis study clearly shows that the electrocardiographic presentation may differ in in all all the the four four cited cited diographic presentation may differ examples of left left ventricular ventricular diastolic overload with examples of diastolic overload with respect to: respect to: (1) The The amplitude amplitude of the the R R wave in lead lead Va V6 considered considered (1) of wave in in isolation. isolation. in (2) The The amplitude amplitude of the the S S wave wave in in lead lead VI V1 considered considered (2) of isolation. in isolation.
RV6 + S V, RYe+SVI be referred to of This This will will be referred to as as the the R:RS R:RS ratio ratio and and is is an an adaptation adaptation of the the ratio by et the in ratio developed developed by Cabrera Cabrera et all al’ to to express express the R R to to S S relationship relationship in lead VI' V,, Ie, le, lead RV, RYI RV,+ S V, I RYI+SV was because aa simple R becomes This ratio This ratio was devised devised because simple R to to S S ratio ratio becomes 50
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FIGURE 2. Graphic Graphic representation of the the relationship relationship FIGURE 2. representation of between between the the RR wave wave inin lead lead V6 V. and and the the SS wave wave inin lead lead V1 VI in the the cases cases of of left left ventricular ventricular diastolic overload. in diastolic overload.
ECG Differentiation
of Left Ventricular
Diastolic
Overload
(Schansroth
eta!)
iL
I
VI Vt
II
III III
AVR AVR
AVI. AVL
AVF AVF
V2 V2
V3 V3
V4 V4
Vs VS
V6 V6
i
- f
---r-l
---I
~
i
!
--+#-t--+---+'-t
I
11'--' -+fl---t--+--jI
~
'
---1-[ 1
~--\-~ -J. -j- j . -
FIGURE FIGURE
-
-
--r--.----j I ' I --, ___ ,, --4.-1---,
---c --,
-
-
3. 3. Electrocardiogram Electrocardiogram showing showing
the features features ofof left left ventricular ventricular diastolic diastolic the overload due to aortic incompetence.
overload
due
to aortic
incompetence.
(3) (3) The The relationship relationship ofof the ~e amplitude amplitude of of the the RR wave wave inin lead lead V6 Va toto the the SS wave wave inin lead lead V1. VI'
(Fig (Fig 22 and and 33 and and Table Table 1). 1). The The R:RS R:RS ratio ratio ofof mitral mitral incompetence incompetence was was signifisignifi-
The The RR Wave Wave inin Lead Lead V6 Vs
cantly cantly higher higher than than those those ofof aortic aortic incompetence incompetence (p
The The RR wave wave amplitude amplitude inin lead lead V6 Va ofof mitral mitral incompeincompe-
ventricular ventricular septal septal defect defect (p<0.001) (p
tence tence was was significantly significantly taller taller than than those those ofof patent patent ductus ductus arteriosus arteriosus (p<0.00l), (p
In In 33 33 ofof the the 41 41 cases cases ofof mitral mitral incompetence, incompetence, the the RR wave wave inin lead lead V6 Va was was two two oror more more times times greater greater than than the the
defect 001). The defect (p<0. (p
electrocardiographic electrocardiographic presentation presentation ofof mitral mitral incompeincompe-
SS wave wave inin lead lead V, VI (Fig (Fig 2). 2). An An example example ofof the the classic classic
of of patent patent ductus ductus arteriosus arteriosus (,p
tence tence isis illustrated illustrated inin Figure Figure 4.4. This This isis also alsQ evident evident
septal septal defect defect (p
from from Figure Figure 22 where where 33 33 ofof the the 41 41 cases cases ofof mitral mitral incompetence incompetence are are located located on on oror above above the the axis axis depictdepict-
lead lead V6 Va ofof patent patent ductus ductus arteriosus arteriosus was was significantly significantly taller taller than than that that ofof ventricular ventricular septal septal defect defect (p(p = 0.018). 0.018).
=
ing the 2:1 2:1 RS RS ratio. ratio. Indeed, Indeed, the the mean mean R:RS R:RS ratio ratio ofof ing the 0.74 0.74 isis significantly significantly higher higher (p
Lead V1 VI
The Wave in The SS Wave in Lead
figure figure which which isis equivalent equivalent toto aa simple simple R:S R:S ratio ratio ofof 2:1). 2:1).
The The amplitude amplitude ofof the the SS wave wave inin lead lead V1 VI ofof mitral mitral
incompetence incompetence was was very very significantly significantly less less than than those tho~e
ItIt isis also also evident evident that that no no case case ofof mitral mitral incompetence incompetence occurs occurs on on oror below below the the YY= XX axis. axis. This This indicates indicates that that
associated associated with with aortic aortic incompetence incompetence (p<0.001), (p
there there are are no no case case ofof mitral mitral incompetence incompetence where where the the SS wave wave inin lead lead V1 VI was was equal equal toto oror greater greater than than the the RR wave wave
=
defect (p
inin lead lead V6. Va. With With aortic aortic incompetence, incompetence, patent patent ductus ductus
with with the the largest largest SS waves waves inin lead lead V,VI (a(a mean mean ofof 24.94 24.94
arteriosus, arteriosus, and and ventricular ventricular septal septal defect, defect, however, however, the the
mm). mm). InIn ten ten ofof the the 32 32 cases, cases, the the SS wave wave inin lead lead V1 VI was was
cases cases were were almost almost equally equally distributed distributed on on either either side side ofof
larger larger than than the the ftR wave wave inin lead lead V6. Va. AA typical typical example example ofof the incomthe electrocardiographic electrocardiographic presentation presentation ofofaortic aorticincompetence petence isis illustrated illustrated inin Figure Figure 3.3. The The SS wave wave amplitude amplituqe inin lead lead V1 V I ofof aortic aortic incompeincompe-
Table Table 2-P 2-P Values Value.for for Comparison Compdrisora ofofthe the Diagnostic DiagfIostic Groups Gmu". with with Respect Bapect toto the the Amplitudes Amplitudea of ofthe the RB Wave Wave in in Lead Lead V6. V., the the SS Wave Wtwe inin Lead Lead V,.V" and and RV,, BV. toto RV6+SVJ BV.+SV,
&tio Ratio
tence tence was was significantly significantly greater greater than than that that ofofaa ventricular ventricular septal septal defect defect (p
-
The The RR toto SS Relationship Relationship The The most most important important differentiating differentiating feature feature for for sepaseparating rating mitral mitral incompetence incompetence from from the the other other causes causes ofof left left ventricular ventricular diastolic diastolic overload overload was was the the RR toto SS relationship. relationsh!p. Thus, Thus, inin mitral mitral incompetence, incompetence, the the RR wave wave inin lead lead V6 Va was was always always taller taller than than the the SS wave wave inin lead lead V1 VI
Diagnostic Diagnostic Comparison Comparison
.
RR Wave Wave Amplitude Amplitude SS Wave Wave Amplitude Amplitude inin V8 Va
inin V1 VI
RV6 RVa RV6+ SV, 1 RV8 +SV
NS NS
<0.001 <0.001
<0.001 <0.001
MI MI with with PDA PDA
<0.001 <0.001
<0.001 <0.001
<0.001 <0.001
MI with VSD MIwith VSD
<0.001 <0.001
NS NS
<0.001 <0.001
Al AI with with VSD VSD
<0.001 <0.001
<0.001 <0.001
NS NS
AIwithPDA AI with PDA PDA with VSD PDAwith VSD
<0.002 <0.002
NS NS
NS NS
<0.002 <0.002
<0.001 <0.001
NS NS
MI MI with with Al AI
CHEST 89 Ii1 CHEST I189
1 /1 JANUARY, JANUARY, 1986 1988
97 97
i
,.........
i~A.
:
I
--j-
I
,
.
!._._~~.~
~..,;.~' 1 -rJ ....-L- i t- ,_. 1--f-- - - f - __+-~I-H+-+--i-+-I+---f---1i • 'i: I I I ----!,--1~1_ 1- .1_ _,f- : i t i! t _ ~1 ___ ----;;----!~II
r. -.-C--
• __ j
I
L-_
I
II
III III
AVR AVR
AVL AVL
VI
V2
V3 V3
V4 V4
VS V5
AVF AVF V6 V6
L_
I
-1-"
':11,
-,
.
J.
A-
the Ieatures features of left left ventricular ventricular diastolic the of diastolic incompetence. overload due to overload due to mitral mitral incompetence.
:'1 .,J
FIGuRE 4. Electrocardiogram Electrocardiogram showing FIGURE 4. showing
--r-
the Y Y = = X X axis, axis, eg, eg, 30 30 below below and 35 above in aortic aortic the and 35 above in incompetence (Fig 2). 2). Furthermore, Furthermore, only two two of of 32 32 incompetence (Fig only cases of aortic aortic incompetence were associated with cases of incompetence were associated with aa simple R:S ratio ratio greater greater than 2:1 2:1 (Fig (Fig 2). 2). simple R:S than Sensitivity, Specificity and Predictive Predictive Accuracy Sensitivity, Specificity and Accuracy The presence presence of an an R:S R:S ratio ratio of of 2:1 2:1 or or higher higher can be The of can be used to diagnose diagnose mitral incompetence with used to mitral incompetence with a sensitivity of of 75. 75.6 6 percent, specificity of 95.4 percent, and aa ity percent, aa specificity of95.4 percent, and predictive accuracy of 91. 91.2 2 percent. percent. The manifestation manifestation predictive accuracy of The of an an S S wave in lead lead VI V1 of of lesser lesser amplitude than the the R ft of wave in amplitude than wave in lead lead V6 can can be be used used to diagnose diagnose mitral wave in Ve to mitral incompetence with sensitivity of 100 percent, percent, incompetence with aa sensitivity of aa specificity of 49.2 49.2 percent and a a predictive predictive accuracy of specificity of percent and accuracy of 56.2 percent. percent. 56.2 100
Mechanisms Mechanisms The normal normal horizontal plane QRS axis axis is is directed directed to The horizontal plane QRS to
A. A.
the left and and slightly slightly posteriorly (as illustrated illustrated in diadiathe left posteriorly (as in gram A of 5). It It is thus usually usually directed to a a region region gram A of Fig Fig 5). is thus directed to midway between the V6 and VI V, lead lead axes. axes. The The impresimpresmidway between the V8 and sion on on these these leads leads ;s is consequently consequently about ie, the the sion about equal, equal, ie, ft wave wave in lead lead ‘6 is of of approximately approximately the same R in V8 is the same amplitude as the S S wave wave in in lead lead V,. must be in VI' ItIt must be borne borne in amplitude as the mind that the horizontal plane axes cannot be localized mind that the horizontal plane axes cannot be localized with the the same same accuracy accuracy or finesse finesse as the the frontal frontal plane with or as plane axes. This This is is due due to to the the variability variability which occurs with axes. which occurs with body build and electrode electrode placement, and which which are body build and placement, and are easily reflected reflected on the the proximity leads of the horizontal horizontal easily on proximity leads of the plane when when compared compared with the the relatively relatively remote leads plane with remote leads of the the frontal frontal plane. of plane. With left ventricular ventricular hypertrophy due to to systolic systolic With left hypertrophy due overload, the magnitude magnitude of the QRS vector is increased increased overload, the of the QRS vector is but the direction is usually maintained so that that the the but the direction is usually maintained so amplitude of the deep S wave wave in in lead lead VI V1 is approxamplitude of the deep S is approximately that of of the the tall tall R R wave wave in in lead lead V8 V6 (diagram (diagram A of of imately that A
B.
B.
------F------'--+~V&
-----I-IIIIIIII:::===:=L+~V.
,.+
,.+ V1
vi V1
FIGURE 5. Diagrams illustrating the horizontal horizontal plane QRS in: A, A, aortic aortic incompetence, incompetence, patent ductus FIGURE 5. Diagrams illustrating the plane QRS vector vector in: patent ductus
arteriosus, and ventricular ventricular septal defect; and B, B, mitral mitral incompetence. incompetence. arteriosus, and septal defect; aild
98 II
ECG DiIIIInIntIaIIo Differentiation of Left Left Ventrtcular Ventricular Diastolic CMrIoad Overload (SchamtDth (Schamroth et a!) ECG 01 DIIItoIIc et e/)
Fig Fig 5). 5). With With left left ventricular ventricular diastolic diastolic overload overload due due toto
consequently consequently result result inin larger larger deflections. deflections. This This
aortic aortic incompetence, incompetence, the the horizontal horizontal plane plane QRS QRS axis axis is is
hypothesis was previously previously put put fbrward forward by by Grant.4 Grant. 4 hypothesis was
similarly similarly directed directed and and increased increased inin magnitude. magnitude. ItIt is,is, CONCLUSIONS CONCLUSIONS
however, however, commonly commonly aa little little more more anteriorly anteriorly placed placed soso that, although both deflections are increased in that, although both deflections are increased in magnimagni-
If, If, inin left left ventricular ventricular diastolic diastolic overload, overload, the the ampliampli-
tude, the RRwave wave inin lead lead V6 Va isis often often slightly slightlygreater greater than than tude, the the the SS wave wave inin lead lead V1, Vb but but this this isis not not invariably invariably so. so. This This
tude tude ofofthe the SS wave wave inin lead lead V1 VI isis equal equal toto oror greater greater than than the R wave in lead V6, the diagnosis of mitral the R wave in lead Ve, the diagnosis of mitral incompeincompe-
occurred occurred inin 21 21 ofof the the 32 32 cases cases (Fig (Fig 2). 2).
tence 001). If, excluded (p
With With mitral mitral incompetence, incompetence, the the ftRwave wave inin lead lead V6 V6 was was
diastolic the ratio ratio ofofthe the RR wave wave inin lead lead V6 Ve toto diastolic overload, overload, the
always always larger larger than than the the SS wave wave inin lead lead V1, Vb and and usually usually
the the SS wave wave inin lead lead V1 VI isis 2:1 2:1 oror greater, greater, the the diagnosis diagnosis ofof
appreciably so. This This isis due due toto important important anterior anterior appreciably so.
mitral mitral incompetence incompetence isis most most likely likely (p
displacement the left left ventricle, ventricle, and and hence, hence, the the QRS QRS displacement ofofthe axis axis asas aa result result ofofthe the enlarged enlarged left left atrium atrium (diagram (diagram BB ofof Fig Fig 5). 5). When When this this occurs, occurs, the the horizontal horizontal plane plane QRS QRS
tence. leftventricular ventriculardiastolic diastolicoverload, overload,both boththethe tence. IfIf,ininleft RR wave large wave inin lead lead V6 Ve and and the the SS wave wave inin lead lead V1 VI are are ofoflarge
axis lead axis axis will will bebeclosely closely aligned aligned with with the the V6 Vslead axis and and will will
magnitude, magnitude, the the most most likely likely diagnosis diagnosis isis aortic aortic incomincom-
tend tend toto bebe perpendicular perpendicular toto the the lead lead V1 VI axis. axis. The The
petence. petence.
impression impression will will thus thus bebe far far greater greater on on the the V6 V6 lead lead axis axis than than on on the the V1 VI lead lead axis. axis. Furthermore, Furthermore, the the defiections deflections
ACKNOWLEDGMENT: ACKNOWLEDGMENT: We We are are indebted indebted toto Doctor Doctor S.S. G.G. Reinach Reinach for for the the statistical statistical analysis. analysis. This This study study was was supported supported byby aa grant grant from from the the South South African African Medical Medical Research Research Council. Councll.
will will bebe ofof large large amplitude amplitude inin lead lead V6 V6 for for the the following following reasons: reasons: (1) (1) There There isis left left ventricular ventricular hypertrophy. hypertrophy.
REFERENCES REFERENCES 11 Cabrera Cabrera CE, CE, Monroy Monroy JR. JR. Systolic Systolic and and diastolic diastolic loading loading ofof the the
J
heart. 1 heart. Am Am Heart Heart J 1952; 1952; 43:66 43:661
(2) (2) The The QRS QRS axis axis isis more more aligned aligned with with lead lead V6. Va. Hence, Hence,
22 Cabrera Cabrera E,E, Muniz Muniz M, M, Prates Prates Flores Flores A,A, yy Costa Costa RochaJ. Rocha J. Semiolgia Semiolgia
its greater on on this this lead. lead. Compare Compare the the its impression impression isis greater
yy electrogenisis electrogenisis del del complejo complejo QRS QRS enen V1. VJ' Prin Prin Cardiolo Cardiolo 1958; 1958;
impression on lead lead V6 V6 inin diagrams diagrams AA and and BB ofof impression on Figure Figure 5.5. (3) (3) The The anterior anterior displacement displacement will will cause cause the the ventricle ventricle toto be be closer closer toto the the precordial precordial electrodes electrodes which which will will
5:335 5:335 33 Neter Neter J,J, Wasserman Wasserman W. W. Applied Applied linear linear statistical statistical models. models. HomeHomewood, wood, IL: IL: Richard Richard DD Irwin Irwin Inc. Inc, 1974:730 1974:730 44 Grant Grant RE RP. Clinical Clinical electrocardiography. electrocardiography. New New York: York: The The Blakiston Blakiston Division, Division, McGraw-Hill McGraw-Hill Book Book Co, Co, mc, Inc, 1957:75 1957:75
CHEST CHEST II 8989 IlI
1 II JANUARY, JANUARY, 1986 1888
99 81