experimental & clinical cardiology

EXPERIMENTAL & CLINICAL CARDIOLOGY

Volume 20, Issue 1, 2014

Title: "Frontal Qrs-t Angle As Predictor of Mortality After Revascularized St Elevation Myocardial Infarction." Authors: Abhishek Sawant

How to reference: Frontal Qrs-t Angle As Predictor of Mortality After Revascularized St Elevation Myocardial Infarction./Abhishek Sawant/Exp Clin Cardiol Vol 20 Issue1 pages 2945-2955 / 2014

Frontal Qrs-t Angle As Predictor of Mortality After Revascularized St Elevation Myocardial Infa...

Experimental and Clinical Cardiology

Frontal QRS-T Angle As Predictor Of Mortality After Revascularized ST Elevation Myocardial Infarction. Original Article

Abhishek C. Sawant,MD,MPH1*, Swapna R. Narra,MD1, Shantanu V. Srivatsa,MS1, Paul K. Mills,PhD2, Sanjay S Srivatsa,MD,FACC1 1 Division of Cardiovascular Medicine, Community Regional Medical Center, Fresno, CA, USA 2 Division of Epidemiology and Biostatistics, University of California at SanFrancisco, Fresno, CA, USA © 2013 et al.; licensee Cardiology Academic Press. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract(( Background:(Frontal(QRST(Angle((FQRST)(has(been(previously(correlated(with(mortality(in(patients(with(stable( coronary(artery(disease.(Its(role(as(a(survival(predictor(following(reperfused(ST(Elevation(Myocardial(Infarction( (STEMI)(remains(unknown.( ( Methods:(We(evaluated(267(consecutive(patients(admitted(to(a(tertiary(care(center(from(January(2007(to(2008(with( STEMI(who(underwent(primary(percutaneous(coronary(intervention((PCI)(or(coronary(artery(bypass(grafting( (CABG).(Data(assessed(included(demographics,(clinical(presentation,(electrocardiograms,(medical(therapy(and(oneR year(mortality.(( ( Results:(Patients(with(FQRST(less(than(50°(had(higher(survival((85.6%)(compared(with(FQRST=51R100°((72.3%)(and( FQRST=101R180°(67.9%),(log(rank,(p=0.011].(Adjusting(for(significant(variables(identified(during(univariate(analysis,( backward(logistic(regression(revealed;(age((Odds(Ratio([OR]=5.13,p=0.046),(female(gender((OR=7.28,p=0.028),(Brain( Natriuretic(Peptide([BNP]((OR=12.97,p=0.046),(cardiac(arrest((OR=29.67,p=0.001)(and(FQRST((OR=2.04,p=0.045)(as( independent(predictors(of(oneRyear(mortality.(Using(these(variables,(a(Risk(Score(ranging(0(to(38(was(developed,(and( had(excellent(discriminatory(ability(for(oneRyear(mortality((C(statistic=0.875([95%CI:(0.813R0.937].(( ( Conclusion:(FQRST(represents(a(novel(independent(predictor(of(oneRyear(mortality(in(STEMI(patients(undergoing( PCI/CABG.(FQRST(based(admission(risk(score(is(simple(to(calculate(and(offers(excellent(discriminatory(ability(for( longRterm(prognosis.( ( Keywords(ST(Elevation(Myocardial(Infarction,(Risk(Score,(Predictors(of(mortality,(Frontal(QRST(Angle,(Percutaneous( coronary(revascularization,(Central(Valley(Risk(Score.(

( 1.(Introduction(( In(patients(presenting(with(acute(coronary(syndrome,(

and( risk( of( mortality( helps( to( determine( both(

predicting( risk( of( adverse( cardiovascular( outcomes(

Various(electrocardiographic((ECG)(criteria(have(been(

immediate( and( shortRterm( treatment( strategies.(

Exp Clin Cardiol, Volume 20, Issue 1, 2014 - Page 2945


used( in( differing( studies( as( prognostic( indicators( for( mortality( in( patients( presenting( with( acute( coronary( syndromes( (ACS).( Population( based( studies( have( shown( that( certain( prognostic( ECG( variables( can( be( used( for( clinical( risk( stratification( for( major( adverse( cardiovascular( events/( mortality.( QRS( duration( has( emerged( as( a( predictor( of( mortality( in( patients( with( left( ventricular( dysfunction( [1,2].( Other( studies( have( shown( that( T( wave( loop( dispersion( and( RRtoRT( total( cosine((repolarization(measurement)(can(also(be(used( for( risk( stratification( post( myocardial( infarction( [3].( FQRST(

Angle(

(FQRST)(

represents(

a(

useful(

electrocardiographic( measure( of( the( dispersion( between( depolarization( and( repolarization.( Recent( studies( have( shown( that( an( increased( spatial( QRSRT( angle(is(associated(with(increased(mortality(in(general( population( [4].( Although( spatial( QRSRT( Angle( is( not( routinely( measure( on( 12( lead( electrocardiograms,( specialized( software( can( easily( be( incorporated( in( ECG( machines( to( calculate( it.( Alternatively( FQRST( can( easily( be( calculated( from( a( routine( 12( lead( standard( electrocardiogram( and( does( not( require( specialized(software.(Studies(have(shown(that(frontal( and( spatial( QRSRT( angles( are( comparable( and( have( strong( correlation( [5].( The( prognostic( role( of( FQRST( in( the( prediction( of( major( cardiovascular( adverse( events( after( acute( STEMI/( ACS( has( hitherto( not( been( studied.( This( study( sought( to( determine( if( FQRST( could( be( used( as( an( independent( predictor( of( all( cause( mortality( in( patients( presenting( with( STEMI,( and( if( FQRST( can( be( used( as( a( variable( in( a( point( of( care( risk( assessment( score( for( predicting( oneRyear( all( cause(mortality.( 2.(Patients(and(Methods:(( ( We(retrospectively(analyzed(278(consecutive(patients( who( presented( to( the( emergency( room( of( a( tertiary( care(hospital(in(central(California,(USA(from(January( 2007( to( January( 2008( with( presumed( diagnosis( of( acute( coronary( syndrome( and( had( electrocardiographic( criteria( for( STEMI.( 11( patients,( who(were(found(to(have(either(preexisting(left(bundle( branch( block( or( paced( rhythm( on( ECG,( were( excluded( from( the( study( leaving( 267( patients( in( the( study( cohort.( Diagnosis( of( STEMI( was( based( on( ST( segment( elevations( measuring( 0.2( mV( in( leads( V1( to( V3( or( 0.1( mV( in( all( other( leads( with( these( changes(

being( present( in( at( least( two( contiguous( leads.( Myocardial(infarction(was(diagnosed(by(symptoms(of( ischemia( and( elevation( in( cardiac( biomarkers,( as( listed(by(the(joint(European(Society(of(cardiology(and( the( American( College( of( Cardiology( [6,7].( A( 12( lead( ECG( as( well( as( basic( laboratory( and( radiographic( investigations( were( obtained( at( the( time( of( presentation(in(emergency(room.(Subjects(underwent( emergent( coronary( angiography( and( based( on( the( findings( underwent( percutaneous( coronary( revascularization( or( coronary( artery( bypass( grafting( based( on( angiographic( and( clinical( findings.( Concurrent( treatment( with( unfractionated( heparin( /( low( molecular( weight( heparin( and( periRprocedural( intravenous( glycoprotein( IIb/IIIa( inhibitors( or( bivalirudin( was( utilized.( ( After( stent( placement( patients(received(adjunctive(dual(antiRplatelet(therapy( with( aspirin( and( a( thienopyridine( antagonist( mostly( clopidogrel.( Mortality( data( during( current( admission( was(obtained(from(hospital(records.(Subsequently(six( months( and( one( year( mortality( data( was( obtained( either( from( hospital( or( California( Department( of( Public( Health( (CDPH)( and( Social( Security( Death( Index( records.( The( main( outcome( chosen( was( all( cause( mortality( in( one( year( since( hospitalization.( All( cause( mortality( was( chosen( as( the( primary( endpoint( since( it( is( not( confounded( by( loss( to( followRup.( Subjects( in( whom( 12( lead( ECG( data( could( not( be( obtained( or( interpreted( were( excluded( from( the( study.( Other( Standardized( scores( R( Thrombolysis( In( Myocardial( Infarction( (TIMIRSTEMI),( Mayo( Clinic( Risk(Score((MCRS)(Global(Registry(of(Acute(Coronary( Events( (GRACE)( score( were( also( calculated.( The( study( was( approved( by( the( local( IRB( of( our( institution.( 3.(12(lead(surface(electrocardiogram((ECG)( ( A( 12( lead( ECG( was( obtained( with( the( patient( in( the( supine( resting( position( using( a( Philips( Page( Writer( Touch( Interpretive( ECG( Machine( (Philips( Medical( Systems,( Andover,( MA,( USA).( The( ECGs( were( obtained(at(a(paper(speed(of(25(mm,(a(gain(of(10(mV( and(a(paper(format(of(3x4.(For(every(patient,(the(first( electrocardiogram( recording( was( used( to( collect( variables( including( heart( rate( (HR),( PR( interval,( QRS( duration,(QT(interval,(corrected(QT(interval,(QRS(axis( and( TR( wave( axis.( FQRST( was( measured( as( the( absolute( difference( between( the( frontal( QRS( and( frontal( TRwave( axis( calculated( as( TRwave( axis( R( QRS( axis(and(if(greater(than(180°(was(subtracted(from(360°( to( obtain( a( continuous( variable( ranging( from( 0°( to( 180°( [8].( Based( on( relative( risk( associated( with(



increasing( values( of( FQRST( they( were( classified( into( tertiles(of(1(to(50°,(51(R(100°,(and(100(R(180°.( ( 4.(Statistical(analysis:( ( The(data(collected(from(medical(charts(and(laboratory( reports( were( tabulated( using( Microsoft( Excel( spreadsheets( whereas( statistical( analysis( was( performed(using(SPSS(Software((PASW(for(Windows,( Rel.( 18.0.0.( 2009;( SPSS( Inc.,( Chicago,( IL,( USA).( Continuous(variables(were(summarized(as(mean(±(SD( (Standard( Deviation)( and( comparisons( between( continuous( variables( were( performed( using( the( Student’s( tRtest.( Categorical( variables( were( summarized( as( percentages( of( the( group( total( and( comparisons( between( groups( were( analyzed( using( either( Fisher( exact( test( or( chiRsquare( test( where( deemed( appropriate.( Correlations( between( frontal( and( spatial( QRSRT( angles,( and( other( variables( were( calculated( using( Spearman’s( Rank( Sum( test( and( Pearson( correlation.( Statistical( significance( was( determined( by( a( pRvalue100( milliseconds( as( an( early( predictor( of( survival( in( patients( presenting( with( acute( coronary( syndrome.( Increased( QRS( duration( may( correlate( with( extent( of( myocardial/conduction( system( disease,( and( hence( arrhythmogenic( potential( [2,3].( In( our( study( graded( QRS( prolongation( and( abnormal( QRSRT( angle,( were( both( associated( with( increased( mortality.( Zabel( et( al( found( in( post( myocardial( infarction( patients( that( measures( of( repolarization( e.g.( total( cosine( RRtoRT( (TCRT)( and( TR( wave( loop( dispersion( are( strong( risk( predictors( for( sudden( cardiac( death( and( arrhythmias( irrespective( of( presence( or( absence( of( left( bundle( branch( block( (LBBB)( [4].( To( assess( both( depolarization( and( repolarization,( the( FQRST( calculates( the( vector( dispersion( between( myocardial( depolarization(and(repolarization.(FQRST(serves(as(a( useful( surrogate( for( damaged/jeopardized( myocardium( at( risk( and( hence( long( term( STEMI( mortality.(Across(gender,(race,(presence(or(absence(of( atrial( fibrillation,( left( ventricular( dysfunction,( or( advanced(conduction(system(disease;(FQRST(retained( powerful(predictive(power(for(longRterm(mortality(in( our( study( population( and( correlated( strongly( with( spatial(calculation(of(QRST(angle.( ( Figure& 2.( Kaplan( Meir( survival( curves( among( patients( presenting(with(ST(elevation(myocardial(infarction(based(on( Central(Valley(Risk(Score((CVRS)(Stratification.(

( National(Health(and(Nutritional(Examination(Survey( (NHANES( III)( data( showed( that( the( distribution( of( QRST( angle( differs( between( males( and( females( with( abnormal( spatial( QRSRT( angle( being( associated( with(

increased( all( cause( mortality( in( both( genders( [16].( In( our( study,( survival( was( significantly( lower( among( females( compared( to( males,( across( differing( distributions( of( QRSRT( angle( between( both( genders.( Smaller( body( mass,( coronary( artery( anatomy,( and( hormonal( influences( may( all( render( the( myocardium( more( susceptible( to( damage( and( less( durable( in( recovery( for( females.( Comparing( multiple( ECG( variables( including( ST( segment( changes,( atrial( fibrillation,( bundle( branch( block,( left( ventricular( hypertrophy,( premature( ventricular( complexes,( and( QRSRT( angle;( Torbal( et( al( found( that( abnormally( widened(QRSRT(angles(had(the(highest(probability(for( predicting(acute(cardiac(pathology([17].(Voulgari(et(al( showed( that( QRSRT( angle( was( strongly( associated( with( systolic( and( diastolic( left( ventricular( performance( in( diabetic( patients( [18].( In( the( present( study,( a( widened( QRSRT( angle( was( associated( with( diabetic( status( and( ECG( measures( of( left( ventricular( hypertrophy.( After( adjusting( for( all( other( ECG( abnormalities,( FQRST( remained( the( most( powerful( independent( ECG( predictor( of( all( cause( mortality( in( our(study.(( ( The( Womanps( Health( Initiative( (WHI)( showed( that( a( wide( QRSRT( angle( was( associated( with( fourfold( increase( in( the( incidence( of( congestive( heart( failure( [19].(In(a(recent(study(of(about(5000(patients(Gotsman( et(al(have(shown(that(FQRST(is(a(powerful(predictor( of( mortality( and( cardiac( related( hospitalizations( in( heart(failure(patients([20].(A(widened(QRSRT(angle(as( a( putative( index( of( jeopardized( myocardium( has( prognostic( significance( for( both( acute( and( chronic( ischemia,( as( shown( in( multiple( populationRbased( studies( [13,( 19,( 21,( 22].( Thus( FQRST( may( act( as( a( surrogate( for( both( ischemic( and( structural( determinants( of( longRterm( survival.( Moreover,( FQRST(appears(to(be(a(valid(marker(for(spatial(QRSRT( angle( in( patients( presenting( with( STEMI( and( avoids( more( complicated( methods( of( vectorcardiography( requiring(specialized(software([18].(The(present(study( performed(in(a(tertiary(care(center(with(an(ethnically( diverse( population( in( Central( Valley,( California( showed( significantly( higher( mortality( amongst( nonR Caucasian( patients,( including( a( high( percentage( of( Hispanic(and(Asian(patients(reflecting(a(broad(ethnic/( racial(diversity(and(high(diabetic(incidence((28%).(The( poor(survival(demonstrated(in(our(study(among(nonR Caucasian( patients( is( conjectured( to( be( secondary( to( higher( prevalence( of( coRmorbid( conditions( like( hypertension,(diabetes(and(ethnicity(driven(anatomic/( physiologic(characteristics.(



Figure& 3.( Receiver( operating( characteristic( (ROC)( Curve( analysis( comparing( the( risk( score( developed( and( actual( outcome( of( oneR year(all(cause(mortality(among((A)(267(subjects(in(our(study(and((B)(500(simulated(bootstrapped(samples.(

(

Age( was( identified( as( a( predictor( of( mortality( in( our( cohort,( which( presumably( reflects( the( association( with( increased( occurrence( of( coRmorbid( conditions( and( cardiovascular( risks.( Another( important( variable( is(the(occurrence(of(congestive(heart(failure(measured( objectively( as( BNP( or( subjectively( as( Killip( Class.( In( our(study(BNP(emerged(as(an(important(independent( predictor( of( survival( presumably( reflecting( overall( cardiopulmonary( decompensation.( A( unique( component( of( the( CVRS( is( the( utilization( of( frontal( QRSRT( angle,( which( reflects( a( divergence( of( the( depolarization( and( repolarization( vectors( of( the( myocardium(and(both(the(long(term(arrhythmogenic( and( mechanical( dysfunction( potential( of( the( jeopardized( at( risk( myocardium.( We( speculate( that( for(CVRS((1)(advancing(age(correlates(with(increasing( comorbidities,( (2)( BNP( elevation( reflects( degree( of( cardioRpulmonary( compromise,( and( (3)( FQRST( widening( is( proportional( to( extent( of( jeopardized( potentially( salvageable( myocardium.( The( strength( of( CVRS( is( its( accuracy,( simplicity,( use( of( easily( measurable( objective( variables,( without( requirement( for( interpretation( of( normograms,( use( of( specialized( computerized( applications( or( diagnostic( handheld( devices.(( ( De( Luca( et( al.( demonstrated( that( patients( with( very( low( Zwolle( risk( scores( could( be( discharged( sooner( from( hospital( thus( reducing( length( of( stay( and( increasing( cost( savings( [23].( Similarly( another( cost( effective(utility(of(CVRS(could(be(the(early(discharge( of( low( risk( patients( in( order( to( reduce( length( of( stay(

and( inpatient( hospitalization( costs.( In( our( study,( patients( with( low( CVRS( (1R10)( had( significantly( shorter(length(of(stay(than(those(with(scores(above(10.( If( this( “low( risk”( population( could( be( identified( initially,( it( could( potentially( provide( much( needed( cost( savings( by( facilitating( early( discharge( while( still( providing(safe(and(efficient(care(after(STEMI.( ( 7.(Study(Limitations( ( Our(study(outcomes(are(derived(from(a(single(tertiary( healthcare( center,( and( may( not( be( representative( of( other( populations.( However,( our( dataset( is( unique( due(to(its(biodiversity(illustrated(by(a(high(percentage( of( minority( population( like( Hispanics( and( Asians,( as( compared(with(predominantly(Caucasian(populations( studied(in(other(major(clinical(trials.(In(this(regard(our( study(is(the(first(study(to(identify(FQRST(widening(as( a( major( risk( predictor( in( NonRCaucasian( (Hispanic( and( Asian)( STEMI( populations.( Cardiovascular( mortality( could( not( be( confirmed( due( to( the( retrospective( nature( of( the( study.( However,( we( suggest(that(for(prognostic(and(risk(prediction(studies( all( cause( mortality( serves( as( a( robust( end( point.( Normal( ranges( for( FQRST( are( well( known( and( may( vary(by(age(and(gender,(however(an(abnormal(QRSRT( angle( is( found( in( up( to( 2%( of( the( general( population( [24].( We( recognize( that( nonRmyocardial( factors( unrelated( directly( to( the( genesis( of( ACS( such( as( autonomic( tone,( electrolyte( and( hormonal( derangements( could( all( alter( Frontal( QRSRT( angle.( Although( the( risk( score( was( internally( validated,( the(



CVRS( needs( to( be( prospectively( evaluated( in( diverse( populations(to(confirm(its(exact(role(in(the(prediction( of(longRterm(prognosis.( ( 8.(Conclusion( The( study( had( provided( several( important( results( in( an( ethnically( and( gender( diverse( contemporary( PCI( treated( STEMI( population.( FQRST( widening( is( an( independent( predictor( of( mortality( in( patients( presenting(with(STEMI(and(can(be(used(for(creating(a( simple( but( robust( “point( of( care”( prognostic( risk( score( (CVRS)( that( predicts( all( cause( mortality( at( one( year.(Finally,(CVRS(can(potentially(be(used(to(identify( low(risk(patients(suitable(for(early(discharge(yielding( potentially(significant(healthcare(cost(savings.( ( Acknowledgements( We( gratefully( acknowledge( the( help( of( Dr.( Mark( T.( Lown( BEng,( PhD,( MBBS( and( Dr.( Chris( P.( Gale( BSc,( MBBS,( PhD,( Med( from( Department( of( Cardiology,( Leeds( Teaching( Hospitals( NHS( Trust,( Leeds,( United( Kingdom( for( their( guidance( and( insight( in( performing(this(study.( ( References( ( 1. Desai(AD,(Yaw(TS,(Yamazaki(T,(Kaykha(A,(Chun( S,( Froelicher( V.( Prognostic( Significance( of( Quantitative( QRS( Duration.( Am( J( Med( 2006;119(7):600R6.( 2. Brilakis(ES,(Mavogiorgos(NC,(Kopecky(SL,(Rihal( CC,( Gersh( BJ,( Williams( BA,( Clements( IP.( Usefulness( of( QRS( duration( in( the( absence( of( bundle( branch( block( as( an( early( predictor( of( survival( in( nonRST( elevation( acute( myocardial( infarction.(Am(Jr(Cardio(2002;89:1013R18.( 3. Zabel( M,( Acar( B,( Klingenheben( T,( Franz( MR,( Hohnloser( SH,( Malik( M.( Analysis( of( 12RLead( TR Wave( Morphology( for( Risk( Stratification( After( Myocardial( Infarction.( Circulation( 2000;102(11):1252R57.( 4. Yamazaki( T,( Froelicher( VF,( Myers( J,( Chun( S,( Wang( P.( Spatial( QRSRT( angle( predicts( cardiac( death( in( a( clinical( population.( Heart( Rhythm( 2005;2:73R78.( 5. ZhuRming( Z,( Prineas( RJ,( Case( D,( Soliman( EZ,( Rautaharju( PM.( Comparison( of( the( prognostic( significance( of( electrocardiographic( QRS/T( Angles( in( predicting( incident( coronary( heart( disease( and( total( mortality(from( the( atherosclerosis(risk(in(communities(study).(Am(J( Cardiol(2007;100(5):844R49.(

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17. Torbal(A,(Kors(JA,(van(Herpen(G,(Meij(S,(Nelwan( S,( Simoons( ML,( Boersma( E.( The( electrical( TRaxis( and( the( spatial( QRSRT( angle( are( independent( predictors( of( longRterm( mortality( in( patients( admitted( with( acute( ischemic( chest( pain.( Cardiology(2004;(101(4):199R207.( 18. Voulgari( Ch,( Tentolouris( N,( Moyssakis( I,( Dilaveris( P,( Gialafos( E,( Papadogiannis( D,((((( Votteas( V,( Cokkinos( DV,( Stefanadis( Ch,( Katsilambros(N.(Spatial(QRSRT(angle:(association( with( diabetes( and( left( ventricular( performance.( Eur(J(Clin(Invest(2006;36(9):608R13.( 19. Rautaharju( PM,( Kooperberg( C,( Larson( JC,( LaCroix( A.( Electrocardiographic( predictors( of( incident( congestive( heart( failure( and( allRcause( mortality( in( postmenopausal( women:( the( Womenps( Health( Initiative.( Circulation( 2006;113(4):481R9.( 20. Gotsman(I,(Keren(A,(Hellman(Y,(Banker(J,(Lotan( C,( Zwas( D.( Usefulness( of( electrocardiographic( Frontal( QRSRT( angle( to( predict( increased( morbidity(and(mortality(in(patients(with(chronic( heart( failure.( Am( J( Cardiol( 2013( Feb( 27;( pii:( S0002R9149(13)00390R1.( doi:( 10.1016/j.amjcard.2013.01.294.( 21. Rautaharju( PM,( Zhou( SH,( Gregg( RE,( StarttR Selvester(RH.(Heart(rate,(gender(differences,(and( presence( versus( absence( of( diagnostic( ST( elevation(as(determinants(of(spatial(QRS|T(angle( widening( in( acute( coronary( syndrome.( Am( J( Cardiol(2011;107(12):1744R50.( 22. Dekker( JM,( Crow( RS,( Hannan( PJ,( Schouten( EG,( Folsom( AR.( Heart( rateRcorrected( QT( interval( prolongation( predicts( risk( of( coronary( heart( disease(in(black(and(white(middleRaged(men(and( women:( the( ARIC( study.( J( Am( Coll( Cardiol( 2004;43(4):565R71.( 23. De( Luca( G,( Suryapranata( H,( van( ‘tHof( ( AW,( de( Boer( MJ,( Hoorntje( JC,( Dambrink( JH,( Gosselink( AT,( Ottervanger( JP,( Zijlstra( F.( Prognostic( assessment( of( patients( with( acute( myocardial( infarction( treated( with( primary( angioplasty:( implications( for( early( discharge.( Circulation( 2004;109(22):2737R43.( 24. Macfarlane( PW.( The( frontal( plane( QRSRT( angle.( Europace(2012;14(6):773R5.( (

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Table&1.&Comparison&of&variables&among&tertiles&of&Frontal&QRST&Angle&on&a&12&lead&ECG&done&during&admission&in& patients&presenting&with&ST&elevation&myocardial&infarction.& Variable

All patients (n=267)

Age (years) Male Gender Body Mass Index (kg/m2) White Blood Count (per µl) Neutrophil/Lymphocyte Ratio Hematocrit (%) Glomerular Filtration Rate (ml/min/1.73 m2) Brain Natriuretic Peptide (pg/ml) Troponin at admission (ng/ml) Peak troponin (ng/ml) Ejection Fraction (%) Diabetes Type 2 Hemoglobin A1C (%) Smoking Hypertension Hyperlipidemia Congestive Heart Failure Previous Myocardial Infarction Length of Stay (days) Heart rate (beats/min) PR Interval (ms) QRS Duration (ms) Corrected QT Interval (ms) Atrial fibrillation T Wave changes ST-Elevation resolution Cardiac Arrest Multi vessel (≥2 vessels) disease TIMI§ Grade 3 Flow Achieved Time to reperfusion (minutes)

Tertile I (QRST Angle 1-50º) (n=118)

Tertile II (QRST Angle 51-100º) (n=65)

Tertile III (QRST Angle 100180º) (n=84)

p- value

62 ±15 187 (70%) 28.29±6.25 11.86±6.14 6.61±7.81 40.81±6.4 92.04±56.21

59 ±14 85 (31.8%) 28.67±6.50 12.67±6.82 6.33±8.51 41.60±6.44 104.67±59.25

61 ±14 44 (16.5%) 29.35±5.84 11.99±5.81 4.88±4.56 40.11±7 92.06±59.11

68±14 58 (21.7%) 26.94±6.03 10.65±5.18 8.32±8.47 40.21±5.85 75.20±44.94