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=OPERATIVE STUDIES

Prognostic significance ofInfarction HndeAnterior Location

PETER H. STONE, MD, FACC. DANIEL S. RAABE. MD. FACC. ALLAN S. JAFFE. MD. FACC.

NANCY CUSTAFSON, MS. JAMES E. MULLEK. MD. FACC. ZOLTAN G. TURI, MD, FACC,

JOHN D. RUTHERFORD, MD. FACC. W. KENNETH POOLE. PHD,

EUGENE PASSAMANI. Mr). FACC. JAMES T. WILLERSON. MD. FACC.

BURTON E. SOBEL, MD. FACC, THOMAS ROBERTSON. MD. FACC.

EUGENE BRAUNWALD. MD. FACC. FOR THE MlLlS GROUP

izosro,,. iMasro< kr,r crr.7

infarction, Ihe hospital c&e and followu~ outcome,mean duralion 30.8 months, ot 47, patients with a (in,inlorction were anat,zad. Aaalyscr were performed grouping the p,ienC according lo infarc, ,~)m,ion snterior, n =253: inferior, n = 218). inSret type (Q wave, n = 32.3:

wilh those wiii, interior infarction, svidawd by a &erinlarct size 121.2 wnw 14.9 B Eqld crealine kinee, MB

O.Oal), serious ventricular e&pie ac,ivi,y (70.1 w&s58.9 . p 4 0.051, in-hmpilaldeath Ill.9 verrur2.8 , P

~erws 58.6%, p < O.Wt), and B hi&. incidence of bmrtfailure (31.9 versus 21.6 . p < 0.05) and in-bospilal death(9.3 versw 4., p < 0.05,. Bawrwr. there was noincravat ra,e of niafarclian or morlatky in hospital

wifh Q R~VC nfarction, and Lotal cardis motilify wnssimibr 116 versus 218, p = NS).

To ewtua,e the rote of infarct twa,ion and type inde.pwlm, of infarct size, patients were group& according 10quartile of inlarc, size. and wtcome was reanalwed wilbin

iniarc,ionexhibi,,daworre hmpi,alcoarseand cumuladwcardiac marfatily than did tbosc with inferior infarclion.uhelber the infarclion was no&, wave or Q wave in Lype.t.tle.tabte analysts of cardiac mortably using Ibr Carpmpordanal hazards regression model demons,ra,rd tba,laeation, bu, no, type, of Infarction exerled an independentpragnastir e,Tw,.

Thus. patienti wilh ant&w infarction experience amore campti&-d hqtW and fat,ow.p course Lb@ donadenl 6,b inferior iafarcdan de&e sdiubwn, for in-

awx&,en, riph, vrntrtcular i~xction in paden@ wilb infe-rior inirclian. resulting in tfs kit vrntricutrir impairment

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The r&five prognos tic sigoifi cancc uf in~finnbntCrlOr from MILIS if they were in cardiogenic shock (Kdlip c lassversu s mfeno r) and ,yf~ IQ wave YEIS* non-Q wave) ofIV). had anadvanced or Lerminal illness had eo artificialmfarcoon remams cootroversm l. Most previous studier havecardiac paccmakcr. or had had an infarction or major sur-addressed the prognostic signiticancc of location or type gery within t he previous 2 weeks. Other exclusion criteria.repam~ly. bug few studies have combined th e analyses to guidelines for standard care and procedures for the admin-ldentlfy the group or groups at greatest risk. Conclusions &ration of hyaluronid ase o r prop~nolol have been reportedhave oflen been conflict ing Some (I-S) have suggested that (2lYpatients wlrh anterior infarction have a worse outcome than Farienrs WWP idunr$ed rrrrospecriv~ly ftor this Trudy onlypatiems wnh mfenor infarction, but others (61 have found if their index myomrdial infarction had been confirmed bythat the increased morlalitv in oaticms with anterior infarc-the Creatine Kinase Core Laboratory. if the index infarction,fion is due solely i the [ creased size ofanterior infxcts andnot to their lo&on. The contr oversy c oncerning the signif-icance of type of infarction is also unresolved. Most st udies(7-14) show that patients with Q wave infarction experiencehigher in-hospaal mortality and morbidity than do patientswith non-Q wave infarct ion and that patients with non-Q

infarction exhibit B higher rate of recurrem infarction andmortality in the follow-up period. Other investigators(15-17). however, indicate that the differences in outcomebetween mfarc? types WC minor and not clinically useful. andsome 118.19) even suggest that the entire clinical and ena-tmlc distmction between Q wave and non-Q wave inhrc-uon is meaningless. Many of the stodles are flawed byutiliz~ooo of smnll sample sizes or patients with previousmfarction.

The purpose of thlr ,tudy. therefore. was to analyze theprognosoc slgniticance of locationortd type of infarct in alarge group of palientb with a first iniarction nho were wellcharacterized m term, of baseline features. h ospital courseznd rebsrqucm outcome. A nalyses were performed byseparately categorizing patients accoidizp o infarct locationand type. th en caiegotizing infarct lo cation with each inbrcttypr. To adjust for diff erences in infarct size be weenantenor and inferior mfarcts, the total cohort ~8s dividedinto quarides of infxct si&e and the $gnificance of infarctlocauon was evaluated.

Methods

Patient po pulation. The patients stud ied were B subgro upof those enrolled Ilbe hlulucen:er lnvestigatios of theLlmitaoon of lnfarcl Sire (MILlSI. a study (20) designed todetermine t he effect of the admimstration of pmpanolol or

hyaluronid ase o n the size oi acute mvocardial infarction.

WBE their first infarction and if the infarction could becharacterized on the basis of ECG location (anterior orinferior) and type IQ wave or non-Q wave). Anteriorlocat ion WBS defin ed as leads I, aVL, VI-V, on the standar dI2 lead ECG and inferior location was defined as leads II.III. aVF, and included a true posterior location with RfS

wave ratio in lead V, >l.O. P&nts with a combination ofanterior and inferior infarction were excluded. The presenceof Q waves was defined as 8. negative deflection 230 ms inwidth and ~0.2 mV in depth. The categorization of type andlocation o f infarction was assigned at the ECG Care Labo-ratory af er review of the ECGs obtained et randomizationand 3 days and IO days later without knowledge of thepatients outcome.

llatn collection. After enrollment. but before randomiza-tion. baseline measurements were obtained, including a I2lead ECG and a rest rddionu clide ventriculogr am. Bloodsemples for measurement of total and MB creatine kinarewere collected hourly during the initial 4 h. at 2 h inter&for the next 4 h, and at 4 h intervals for the subsequent 72 hthroug hout t he remaining hospiral stay, as previously re-ported (20). Radionuclide ventricul ography was repeated onday IO. The left ventricu lar ejection fracti on from m ultisatedequilibrium blood pool scintig raphy was calculated b y astandard technique using a background -corrected coontmethod from the left anterior obl ique view (21). A subjectiveanalysis of left ventricular regional wall motion wes per-formed with the left ventricle divided into II segmentsromthe anterior and left anterior oblique projections , ils previ-ou$ly descri bed (22). A I2 lead ECG was obtained at 90 minand et 72 h after initi ation of tnerapy and again on day la. A24 h Holler ECG recording was petiomxd on the day NJ. Serious ventricular ectopic activity was defined as the

oresence of z-6 ectooic beats/h, bieeminv, multiform confin-Patients were ebgible for enrollment in.MlLIS if they satis- iration or ~3 coniecutive ecto& be&. Historical fied the following inclusio n and exclusion criteria and if theyphysical examination data. R summa~ of daily clinicaland their phyvci an provid ed infor med consent. The inclu-events, vit al s igns and the results of special procedures andsion criter ia were: age schcmiu. and demonstration of cIcc-pitaliration.trocardlo graphic (ECG) cnreria of acute myoc~~dial ische- Follunvp visPs IU UIIYSJ itr rurval history and physicalmia or cvolwog miarct ion (new Q WBYCS >30 mb in wiuh rxaminarion were schedul ed at 3 and 6 months f or alland ~11.2 mV in depth or STaegment elevatio nor depression enrolled p atients. At 3 months, a rest and exercise radion u-~0.1 mV in al lea,t two related leads) or left bundle branchelide ventriculogr am was performed and at 6 months ablock oi idiovcn tncular rhythm. Patients were excludedtreadmill cxercis c test was pcrform cd. Subsequently. the

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Compared with patients with Q wave ulfarction. patients

with non-Q wave infzction exhibited a significantly smaller

infxcl (12.7 verws 20.7 5 Eqlm. p < 0.0011. and a betterpreserved left vrntricular ejection fraction on admission (51versus 44 p < 0.00,) arid at day IO (55 versus 45 . p