METHODS. New Perspectives In the Assessment of Cardiac Chamber Dimensions During Development and Adulthood. April 1992 :9Ba_8

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1 JACC Vnl. 19, Nn. A April 1992 :9B_8 943 METHODS New Perspectives In the Assessment of Crdic Chmber Dimensions During Development nd Adulthood STEFAN M. NEDORF. MD, MRRS, MICHAEL H. PICARD. M D. FACC. MARCO O. TRIULZI, MD, JAMES D. THOMAS, MD. FACC. JOHN NEWELL, 13 A, MARY ETTA K ING. MD. FACC. ARTHUR E. WF, Y MAN. M D. FACC 8vurwe,.lunrckrrsetr The use of body surfce re to ssess the normlcy of crdic dimensions hs severl limittions. To determine whether crdic dimensions cn be ssessed by other Indexes of body size nd growth, this study evluted the reltions between crdic dimem ssessed by two-dimensionl echocrdiogrphy nd ge, height, weight nd body surfce re. The study group included 268 norml persons ged 6 dys to 76 yers of ge. The dimensions exmined included the ortic nulus, left trium nd left ventriculr end.dinstolic dimeter, ech mesured in the prsternl long-xis plne, nd left ventriculr length mesured from the picl twnwhmher view. The nlysis confirmed tht the hert nd gret vosels grow in unison nd t predictble rte fter birth, reching 50% of their dult dimensions t birth, 75%r by 5 sers nd 90 % by 12 yers. Although ech crd in dinteruin relted linerly with height lctic nnulus, r = 0.96 : left tinm, r = 0.91 ; left venteiculrdirneter, r = 0.94: left ventrireter length, r = 0.93), the rottions mong ge, weight nd body surfce re were best.,messed by grrdrlic equtions. Multiple regression eotdrnmd tht fter djustment fr height, other indexes including ge, gender, weight nd body surfce re hd no independent effect or the prediction of ech dimension. Therefore, becuse height is ntderived vrible tht reltes linerly with crdic dimension independent of ge, it orers simple yet ccurte mens of ssessing the normlcy of crdic dimensions in children nd dults. (J Am C11 Cordil 1992 ;19:983-8) To be cliniclly meningful. the norml limits of crdic dimensions must tke into ccount their dependence on body size, nd to be cliniclly useful the method of indexing body size must be ccurte, discriminting nd, preferbly, simple to use. Although body surfce re is widely used s n index of body size when ssessing the normlcy of crdic dimensions, its use hs been chllenged on boil] theoretic (I) nd mthemtic (2) grounds. In ddition, the body surfce re index hs certin clinicl limittions becuse it is difficult to estimte without reference to specilized tbles, is subject to vribility in individul subjects becuse of chnges in body weight nd hs nonlinerreltien with medie dimensions, restricting its discriminm potentil in dults (3.41. Therefore, to determine whether crdic dimensions might be more redily nd more meningfully ssessed by other indexes of body size nd growth- we evluted the reltions between crdic dimensions determined by two dimensionl echocrdiogrphy nd ge, height, weight nd body surfce re during erly development nd dulthood. "Dr. Nidort ws supported by the Ntiret Sen Feund ien of,lusulie, Cnberr. Austrlin Cpitl Territory. Austrli. From the Noninvsive Crdic Lbortory. Musschusens Generl Hs pilot, Boston. Msschusetts. Mnusedpireceived August8,1991 :r,vis,dmnscriplmctivtjoctober ccepted November 4, 1991, Address fur reeriuls: Stefn M. Nidurf, MD, Mns, Non-invsive Crdic Lbortory, Phillips B. htsspchuseus Crrot Hospitl. oston, Msschusetts by the Americn College of Crdiology Methods Shols, ptients, The study cohort consisted of two groups. Group I consisted of 196 children, including 99 boys nd 97 girls. who were ssessed s prt of n echocrdigrphic study of well children. These were not children referred for suspected crdic disese nd no child ws hospitlized for ny cuse. Inclusion in the study demnded the bsence of ny systemic or crdiovsculr disese. The ge of this group rnged from 6 dys to IS yers (men 4.5 yers!. weight from 2.3Itt 86 kg (men 19) nd height from 37 it, 188 cm (men 98). Group 11 consisted of 38 mle nd 34 femle dult volunteer employees of the Msschusetts Generl Hospitl who, on the bsis of history, physicl exmintion, elecirncrdiogrm nd chest rdiogrph, hd no crdiovsculr or systemicdiscse.theirgernged from I8to76yers(men 381. nd their height nd weighs from I55 to 180 cm (men 169) nd 40 to 80 kg (men 701, respectively. The men height nd weight percentile of the entire cohort ws 55 '- 30`: nd 51 S 30%. respectively. Dt cquisition. Stndrd two-dimensionl echucrdiogrphic Imges (5) were obtined with n ATL 300 mechnicl sector scnner with use of 3.5 t 5 MHz trnsducer nd recorded with Pnsonic video recorder on 0.5 in, (1.27 cm) videotpe. After ech study ws reviewed, only those imges displying optiml systolic nd distolic orien- 0nstt97»1_55.00

2 984 sitxitsf CO Al., ASSESSMENT OF CARDIAC nlxte\ 5 tons ]ACC vol. 19 Ne 5 Awl 1992:983- Migure 1. The tile l which ech dimension ws mesured. A, Mximl dimeter of the ortic (Aol nulus jl I. It, The left trium (LAI 12] nd left vcmricte (LV} 131 x ured Rom the prsternl long-xis view. C, Left ventriculr slcngth 14] ws mesured from the pi :l twwchmber view, Lotion nd structurl definition were copied onto video disk from which the mesurements were mde. The end-distolic dimeter of the ortic nulus nd endsystolic (mximl) dimeter of the left trium were both mesured from the prsternl long-xis view, s ws the mximl distolic dimeter of the left ventricle. The distolic length of the left ventriculr cvity ws mesured from the picl two-chmber view (Fig. I). Ech dimension ws mesured with the "inner edge convention," which uses the innermost, bright edge reflection s contour, s indicted by the rrows in Figure I. All mesurements were mde by the sme observer (M.O.T.), with clibrted electronic clipers (Microsonics Esy View 11 imge nnlysi system). The introbserver error ws clculted to be 4% (6), Clinicl detils including ge, gender, weight nd height were collected t the time of echocrdiogrphic study. The body surfce re ws derived from stndrd formuls (7). Sttisticl nlysis. The strength of the reltion between ech crdic dimension nd ge, height, weight nd body surfce re ws ssessed by using the Person correltion ceebcient Cr vlue). Multiple littcr regression nlysis ws used to determine the influence of gender on ech of these reltions, nd to determine which fctor or fctors hd the strongest influence on dimension (9). The Student t test ws used to determine whether the ge-relted chnges in crdic dimensions were the sme for ech dimension exmined, Results Reltion between ge nd crdic dimensions. Figure 2 demonstrtes the reltions between ge nd dimensions of the ortic nulus, left trium nd left ventricle in subjects 19 yers of ge (Group I). Although the bsolute vlues for ech dimension differ, the rte of growth of ccti of these structures, expressed by the slope of ech of these curves, ws not significntly differen. Hence by birth, the mesured dimensions of the ort, left trium nd left ventricle hve reched lmost 50% of their dult vlue, nd hve incresed to lmost 69% of This vlue by 12 to 18 months of ge, Subsequently the rte of growth slows, so tht by 5 yers these structures hve ttined 75% of their dult dinrension, nd by the time of puberty (12 to IS yers of ge) they hve reched 90 % of their dult dimension. After puberty, the rte of crdic growth slows even further, nd significnt increses in crdic dimensions re not seen fter 15 yers of ge. Muhipte regression nlysis demonstrted tht the pttern of growth ws independent of gender. The 95% confidence intervls on the ge curves re similr to those obtined from the dt minting body surfce re to dimension, reflecting the strong reltion between ge nd body surfce re in the peditric ge group. Reltion between crdic dimensions nd body surfce re, weight nd height. Figure 3 illustrtes the reltion between the dimeter of the ortic nulus nd body surfce re, weight nd height, respectively. The reltion between body height nd the left tri) nd left ventriculr dimensions (dimeter nd length) is presented in Figure 4. These scttergrms include dt from both Group I nd Group IF Univrfre nlysis confirmed the presence of strong reltion between ortic nulus dimension nd height (0.961, weight , body surfce re 10, 93) nd ge 10.73). Indeed the sme trends were seen for ech dimension exmined. However, lthough the reltion between ortic nulus dimension nd both weight nd body surfce reis nonliner, nd best expressed by qudrtic eqution, the reltion between height nd the dimensions of the ortic nulus, left trium nd left ventricle is liner. Mulitple regression nlyses confirmed tht fter djustment for height, other univrile predictors of ortic nlog nd ventriculr dimensions hd no dditionl independent influence on the estimte of the norml rnge of these structures. For exmple, in the nlysis used to exmine the determinnts of ortic nulus dimension, the F vlue for height ws 2,560 versus 10, 4 nd 3 for ge, weight nd body surfce re, respectively. Similr results were obtined in the models exmining the determinnts of left tril nd ventriculr dimeters, For this reson, liner model contining height s the only vrible ws derived s mens of predicting the norml dimension of ech structure (Tble I). Although multiple regression nlysis snvgested tht weight should be included --pith he'5ht in the model to predict left ttl dimension (Left tril dimeter = t Height] + (0.007 x Weights + (3.93), the rnge of dimensions predicted by this eqution ws not significntly different from tht estimted with the univrite model contining height s its only vrible (Tble I). For exmple, in person

3 1ACC Vnl. 19. N, Andltmson_s N1WIRr t'1' AL -~sci SSMT->r OF t'seobic DIS1ENs(Ns t2 IS Age (yers) I Age (yers) 6 C YA o f, t5 Age (yers) IN L2 15 Is Age (yers) 170 cm tll weighing 70 kg, the univrite eqution estimtes tril dimeter to be 3.07 cm, wheres the heightlweight formul predicts left tril dimeter to be 3.12 cm. Recuse this difference (0.05 cm) is beyond the resolution o the technology used to mesure the dimension, the improvement in the predictive model cnnot be considered to be cliniclly significnt. Figure 5 shows the reltion between body surfce re nd bth weight nd height nd demonstrtes tht the reltion between these vribles becomes "dissocited" once body surfce re increses beyond t. However, s body surfce re continues to increse, its mjor determinnt ppers to relte to weight gin rther thn to increses in body height. Figure 2. Reltion between ge nd the (A) ortic nulus dimeter, (R) left tril dimeter, ICI ]rt ventrculr dimeter nd (DI left ventriculr length in Group 1 (<19 yers of no). The men nd 95% confidence limits of the dt re represented by the solid nd dotted lines, respectively. Discussion Although the concept of indexing crdic dimension to body size cn be trced s fr bck s 1888, when Hosselin (9) reported the reltion between body weight nd ortic nulus dimeter, the ides] mens of indexing crdic dimensions, which needs to be ccurte. discriminting nd, preferbly, simple to use, is yet to he defined.

4 986 NI000F I T AL, AS5k55MvvC 111 CAKUITC UINLNFII h. CALL vol. Is. No, 5 Aervl A r c L -- I ss I Body Surfce Are zzo Body Weight (kg) E 2.n 1.5 e 1.11 Figure 3. Reltion between ortic snubs dimeter nd 1A) body surfce ur. (B) body elghl tht nd ICI Body height (em). Group 1: 0 = Group II. 0 Q Body Height (cm) Zoo Crdic dimensions versus body surfce re. The current prctice of indexing linercrdic dimensions determined by echocrdiogrphy to body surfce re ws estblished in 1975 by Pystein et l. (101. who reportod the first lrge series of norml cchocrdiogrphic mesurements in children nd dults. Although this trend hs continued ( ). the use of body surfce re s mens of djusting for differences in body size hs severl limittions tht restrict its use in clinicl p rctice. l i It is difficult to derive ptient's body surfce re without reference to specilized tbles; 2) body surfce re my vry in the sme person becuse of chnges in body weight : nd 3) body surfce re fils to provide insight into the mjor determinnt (height vs. weight) of crdic dimension during development. Furthermore, becuse the reltion between body surfce re nd crdic dimensions is nonliner (Fig. 3), the common clinicl prctice of simply dividing dimensions by body surfce is mthemticlly incorrect nd my led to ennneous results in some clinicl circumstnces (2). In view of these clinicl limittions, it would be desirble to develop normtive dt for the echocrdiegrphic ssessment of crdic chmber dimensions bsed on mo,e redily obtined indexes such s ge, height or weight lone. Crdic dimensions verses body height. The most striking observtion in this nlysis ws the strong liner nture of the reltion between ech crdic dimension nd body height. which ws demonstrted to be independent of ge nd gender. These observtions suggest tht during development, crdic dimensions increse primrily in response to skeletl growth. Furthcrmnrc, the strength 01' these rel-

5 J.4CC dcl. 19, Nu.. April L9,2:93-s tii177)rf FT A t srs,so-.~i ~ifcae171a4 ll141f,vslovs 4 A u C t 2n s Body Height (cm) Body Height (om) too s sob Figure 4. Reltion between height nd (A) left tril dimeter, (Il) left _. ventriculr dimeter nd (C) let) vemdculr length. - Group L C = Group It. dl e Body Height (cm) lions my explin the nonliner nture of the reltion between crdic dimensions nti body surfce re. Tht is, becuse height is no longer we or determinnt of body surfce re fter vlue, of 1.5 (Fig. 5). it would be predicted tht increses in body surfce re due to increses in weight Tble 1. Liner Regression Equtions Used io Predict Crdic Dimensions 'Height in cm. Egwtien Aortic nels (ces) Height. r 0,25 Le slm x Height Left ventriculr dimeter x Height Left ventriculr length x Height would not be ssocited with further increses in crdic dimension. The clinicl relevnce of this observtion is tht it suggests tht short obese persons should hve smller crdic dimensions thn those of tll sthenic persons even when their body surfce re is the sme. Hence fr clinicl purposes, body height ppers to be n idel mens of indexing crdic dimensions becuse it is simple, relibly obtined, nondcrived vrible tht reltes linerly to crdic dimension nd is not subject to chnge during illness. It offers prticulr dvntge in the ssessment of obese dults nd children. becuse in these ptients the estimted rnge of crdic dimensions bsed on body surfce re is very wide (Fig. 3). Crdic dimensions versos ge. The reltion between ge nd crdic dimensions is cliniclly relevnt becuse it

6 988 NInf:RF ET AI At.Br.SM[NTOFCARDIAC DIMMEN51t)N 5 JACE Vrl 19. 9c. 5 Atoll 190 ;991-z Z ~plo u o ~ He z its nonliner nture (Fig. 181, nd becuse weight is sub?ect to vribility in the sme person. Conclusions. Although there nrestrnngrcttiernshcrween crdic dimensions nd ge. weight. height nd body surfce re, it ppers tht height is the strongest predictor of crdic chmber dimensions both during development nd in dulthood. Furthermore. becuse height is simple, relibly obtined, nonderived vrible tht reltes linerly to crdic dimensions independent of ge, the presenttion of normtive dt in reltion to body height should prove useful in the echocrdiogrphie ssessment of crdic chmber III dimensions. 40 C-0, Body Surfce Are Figure 5. Reltion between body surfce re nd height Nl nd weight 101. As body surfce re increses beyond I, the mjor determinnt of body surfce re is weight rther thn heightl confirms tht the hert nd gret vessels grow in - rnison nd t predictble rte fter birth. Hence, it: the peditric ge group, it my be pproprite to index crdic dimension to ge lone to determine whether crdic size nd the rte of crdic growth rc norml. An pprecition of these reltions my id in the timing of surgery in children with vlvulr hert disese, becuse they provide informtion bout the projected tdull) size ofthe ventricle nd nulus in ny prticulr child, However, lthough ge offers simple mens of ssessing crdic dimensions in young well children, the reltion might fil in the ssessment of crdic dimensions in chroniclly ill children whose ge-relted growth curve my differ from norml. Crdic dimensions Versus body weight. Although strong reltion ws found between crdic dimensions nd body weight, use of this reltion s mens of indexing crdic dimensions is limited, especilly mong dults, becuse of References I. Tnner 1M. Fllcy of per weight nd per surfce non nindgrds. nd,heir d.tien to sp,,is cmclnon. J Applied Physinl 1949 :2.1-J6 2. Gtgcse)l IIP, Remold CM. Growth of the humn hert reblive to hod) surfce ure. Am J Crdiel 1990:65 : Ped,nn 1D. Tduli MO, King ME. Newell 1. Weynres AE. Limits or norml left venth edr dimensions in grov.4h cnddevelopmenl: llttis of dimensions nd vrince in the two dimensionl tenecrdiopems of norml helthy subjects. 1 Am Coll Cordil 1982' Perlmn 1D. Triulci M0. King ME. Abused V, Weymn AE Loll url dimrnsius in growth nd devekrpmer; n mt limits for Ice' dime, 'orscl echocrdiogrphy. J Am Coll Crdml Weymn AE. Cr.-sectionl EchocrdiounphY. Phildelpbi Le & Fe4er. 1982: Trils 610. Gill- LD, Gentile F. Nc..ell In. Weymn AE. Normn dult cross sectionl echocrdiogrphie vlues : dimn :ios nd chmber n. Echocrdiogrphy 1984 ;1 : on Orls D, Du Bls EF. Chnhl eiwomerery. X. A formul to estimte the pprozimtc surfce re if height nd weight he known. Arch (nicer Mod 1916 :17 : Brown MB, Engl.- L. irr m ish Rl. ds. BMJDP-Sed6 luu softwre Mnul. Vol 2. Berkeley, CAA University of Ctfomin Press, 1990 : Hosselin HV. Usher die Urscche der Scheinbren Abhngigkeit des Umstme von der Grossc der Kdrperbeltinhe. Arch Afr Physiol 1168 : Epstein ML, Goldberg SJ. Allen HD. Keneeke L, Wood 1. Gret vessel, crdic chmber nd wll growth pttern in norml children. Circultion 1975 :31 : Henry WL, Wre 1. Gmin JM, Hepner 51, McKy 1. Weiner M. Echcrdioge.phic mesuremems in norml subject. Growth relted chnges tht occur between infncy nd erly duhhood. Circuhtion : 'eigenhum H. Echocrdiogrphy. 4th ed. Phddelpltiz.I.. & Feblger : 1981 :626-8.