echocardiographic abnormalities in the mitral valve prolapse syndrome

Echocardiographic Abnormalitiesin the Mitral Valve Prolapse SyndromeBy RICAIRD L. Popp, M.D., OWEN R. BROWN, JAMES F. SILVERMAN, M.D.,

AND DONALD C. HARRISON, M.D.

SUMMARYTwo echocardiographic patterns of the mitral valve have been found to correlate with ana-

tomic and/or angiocardiographic appearance of redundancy of the mitral valve. The echocardio-graphic abnormality may be found in the presence or absence of auscultatory findings, while theapparent separation of the anterior and posterior mitral leaflets on echocardiogram does not seemto represent anatomic separation leading to mitral regurgitation. Since the echocardiographic ab-normality is found in the absence of various parts of the syndrome, it may be used as a tool todiagnose the mitral valve prolapse syndrome, discover its incidence and follow its natural history.

Additional Indexing Words:Ultrasound Midsystolic click-late systolic murmurFloppy valve syndrome Angiocardiography Phonocardiography

PULSED REFLECTED ULTRASOUND, orechocardiography, was first used by Shah and

Gramiak' to study patients with the clinical syn-drome of mitral valve prolapse. Echocardiogramsfrom patients with the midsystolic click-late systolicmurmur syndrome have also been reported byKerber, Isaeff and Hancock2 and by Dillon et al.3In each of these preceding series, patients wereknown to have specific clinical auscultatory find-ings, and inferences regarding the mechanism ofmurmur generation were made from the echograms,invoking apparent separation of the mitral valveleaflets to account for the mitral regurgitation. How-ever, by screening patients prior to cardiac cath-eterization, a spectrum of clinical features has beenfound in patients with the echographic findings ofmitral valve prolapse. This report describes a groupof 20 patients studied clinically, with phonocardio-

From the Divisions of Cardiology and Radiology, Stan-ford University School of Medicine, Stanford, Califomia94305.

Supported in part by NIH grants HL-5709 and HL-5866.Dr. Popp is supported in part by a Research CareerDevelopment Award, K04-HL-704-39, and a grant fromthe Bay Area Heart Research Association.

Presented in part at the 45th Scielntific Sessions of theAmerican Heart Association, Dallas, Texas, November 1972.

Address for reprints: Dr. Richard L. Popp, CardiologyDivision, Stanford University School of Medicine, Stanford,California 94305.

Received September 6, 1973; revision accepted for pub-lication October 31, 1973.

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Mitral regurgitation

gram and echocardiogram, and having confirmationof mitral valve prolapse by cardiac catheterization,left ventricular angiocardiography and, in six cases,by surgery.

Materials and MethodsThe twenty patients selected for analysis were those

undergoing diagnostic cardiac catheterization and leftventriculography from September 1971 to May 1972 atStanford University Medical Center, in whom echocar-diograms suggested mitral valve prolapse. All patientsadmitted for cardiac catheterization at Stanford Uni-versity Hospital undergo echocardiographic and phono-cardiographic studies one to two days prior to catheter-ization.

Echocardiograms were performed using a Smith-KlineEkoline 20: Mark II or IIA ultrasonoscope and 2.25MHz transducer of 0.5 inch diameter, with acousticlens collimating the sound beam for 5 cm tissue depth.The echocardiograms were recorded on Polaroid photo-graphs of the oscilloscope or strip chart recordings,using an Electronics for Medicine DR8 recorder orHoneywell #1856 visicorder. The patients were studiedin the supine position, with the transducer placed onthe chest wall at the left sternal border. The interspacechosen would allow recording of the anterior and poste-rior mitral valve leaflets with the transducer orientednearly perpendicular to the chest wall. Care was takento record the anterior and posterior mitral valve leafletsnear their free edges. By rocking the transducer at oneposition on the chest wall, the anterior leaflet was re-corded from its annular insertion to its free edge. Re-cording the posterior leaflet was accomplished by rock-ing the transducer to encompass the area from thepostero-lateral left atrium across the mitral annulus tothe posterior left ventricle. In addition, in most cases

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MITRAL VALVE PROLAPSE SYNDROME

the tranisducer was placed in the initerspace below thatjust described, so that the sound beam could be directedthrough the mitral valve and into the left atrium.

Phonocardiograrns were recorded using a Maico con-tact microphone placed at the cardiac apex and filteredto display frequencies of 120 to 500 Hz and 40 to200 Hz. Angiocardiograms were performed at approxi~mately 390 right anterior oblique projectioni, uisinig 0.5-0.7 cc/kg contrast material injected at 10-12 cc/sec.Cineangiocardiograms were filmed at 60 frames/sec.

ResultsThe results of this study are summarized in table

1. Thirteen patients showed the echocardiographicabnormality which has been previously reported inthe midsystolic click-late systolic murmur syn-drome.1-" That is, during systole the normal patternof gradual anterior migration of the closed mitralleaflets (.fig. 1) is replaced by the pattern of aninitial horizontal, slight anterior or posterior mo-tion, followed by an abrupt posterior motion, whichresults in a configuration that resembles a questionmark turned approximately 900 clockwise (fig. 2).2 SIn 12 of these 13 patients, the association of a mid-or late systolic click or late systolic murmur orcombin:ation of midsystolic click and late systolicmurmur could be heard and recorded. These find-ings on the phonocardiogram were variable duringa single examination in five of these twelve patients,while the echocardiographic findings were constant.One of the 13 patients showed the echocardio-graphic pattern just described, but in this patientno phonocardiographic abnormality could be found,despite changes in position, amyl nitrite administra-tion and perforrmance of Valsalva's maneuver (fig. 3).This patienit was being evaluated for chest pain,and the echocardiographic abnormality was an un-

Table 1Echocardiographic, Phonocardiographic and Angiocar-diographic Findings

No. pts. Echocardiogram Phonocardiogram Angiocardiogram

12 MSN MSC, ESM MV prolapseMSC-LSM (7 mitral(5 variable) regurgitation)

1 MSN 0 MV prolapse5 ESPM Part-systolic

murmtur MV prolapse andmitral regulrgitation

1 E8PM Mxiltiple clicks MV prolapse1 ESPM 0 MV prolapse

Abbreviationis: MSN mnidsystolic notch; MSC - mid-systolic click; LSM = late systolic muirmrur; MV = mitralvalve; 11SPM early svstolic posteriotr motioni; 0 = noabnormality.Circulation, Volume XLIX, March 1974

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Figure 1

Mitral valve echogram from a clinically normal subject. Thesystolic pattern is of gradual anterior motion toward thetransducer (top). Two echoes with the waveform of theanterior leaflet (al) are recot.ded. One of these echoes (whitearrow) is more intense but has less excursion than the secondecho. During systole there is apparent "separation" of theseechoes. Although the echo showing the posterior leaflet (pl)waveform is near the second anterior leaflet echo during sys-tole, some variable separation is seen (black arrow). Thep)osterior leaflet could be recorded only with the left veti-tricnlar posterior wall (LVPW) posterior to it. IVS =inter-ventricular septum; ecg electrocardiogram.

suspected finding. The remaining seven patientsshowed an echocardiographic abnormality duringsystole, which was characterized by an early systolicposterior motion of the mitral valve.' In these casesthere was smooth posterior motion of the mitralleaflet echoes toward the left atrium from the onsetof systole, apparently reaching its nadir duringmidsystole, and then moving anteriorly again inthe latter half of systole (fig. 4). The resultant formis that of a U-shaped wave, beginning with closureof the mitral valve and ending with opening of_s ^_ ~~~~~~ECG

Fig-ure 2

Simultaneous electrocardiogram (EGG) lead II, apex phono-cardiogram (PHONO) and echocardiogrdm from a patientwith a late systolic murmur, T wave abnormalities and an-giographic mitral valve prolapse. The anterior mitral valve(MV) leaflet echoes meet the posterior leaflet echoes at theonset of systole (black arrow). These echoes move slightlytoward the chest wall (GW) in early sys-tole, but show anabrupt posterior motion toward the left atrium (LA) in latesystole, coincident with the recording of the murmur (s-r).Note the multiple echoes during systole. IVS = interven-tricular septum.

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POPP ET AL.

Figure 3

Simuitltanieous electrocardiogramt (EGG) lead II, phonocardio-grams (PHIONO) with 120-500 Hz band-pass filters fromsecond irnters pace at left sternal border (PULM) and apex,and echocardiogram. During diastole, echo waveforms ofbothll anterior and posterior mitral leaflets were recorded.Despite apparent separation of the echoes, no systolic mur-muiir wcas recorded (and none could be heard). The leftatriumi is recorded posterior to the valve echoes.

the valve. Five of these seven patients had a pan-systolic m-urmur recorded on the phoniocardiogram,while one patient showed multiple systolic clickswithout murmur (fig. 5). In the remaining patient,with radiographic dilation of the pulmonary artery,the early systolic posterior motion was recordedon the echogram, but no phonocardiographic ab-normality could be founid with position change,amnyl nitrite administration, or Valsalva's maneuver.More than two echoes were recorded from the

mitral valve leaflets in all patients, and the num-ber of apparent mitral leaflet echoes recorded dur-

ECG.-

AL.

PU,

ing systole was greater in these patients than innormals. Both anterior and posterior mitral leafletswere recorded while directing the sound beaminto the left atrium in six patients.

All patients had the angiocardiographic pictureof mitral valve prolapse (fig. 6). Twelve of thetwenty patients had associated mitral regurgitation.There was no correlation between angiocardio-graphic mitral regurgitation and the apparent sepa-ration of the multiple echoes from the mitral valveleaflets after their meeting at end-diastole (theC-point). The diagnosis of "floppy mitral valve"xvas confirmed at surgery in six patients.

DiscussionIn normal patients, the basic systolic mitral wave-

form is that of gradual anterior migration towardthe chest wall (fig. 1) .2 ' This seems to be theresult of reduction in volume of the right and leftventricles during systole. Consequently, the closedmitral leaflets are closer to the chest wall at end-systole than at end-diastole, although they have notundergone motion independenit of the mitral annu-lus.4 In high-quality echocardiograms, it is possibleto see a small initial posterior motion of theseleaflets at the onset of systole, which lasts for lessthani 0.05 seconds (fig. 1). In the piatients withmitral valve prolapse, the echogram records pos-terior motion of the leaflets during systole, which

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Figure 4

Echocardiogram from a patient with an apical pansystolicmurnur who showed mitral valve prolapse and mitral re-

guirgitation on angiogram. The anterior mitral valve leaflet(AL) and posterior leaflet (PL) echoes meet at the onset ofsystole (large black arrow). Posterior motion of these echoeshcgins early in systole and is reversed in mid-systole (whitearrow). The small black arrow marks the point of separationof echoes with the waveform of the anterior and posteriorleaflets at early diastolic valve opening. This suggests thatthe anterior and posterior leaflet echoes did not separateduring systole, although multiple echoes are recorded. ECG-electrocardiogram.

Figure 5

Simultaneous phonocardiogram (PHONO) recorded at thecardiac apex, lead II electrocardiogram (ECG) and echo-cardiogram. Dturing diastole, echo waveforms of both theanterior (AL) and posterior (PL) mitral leaflets were re-corded. Dturing systole, an early and prolonged posteriormotion was recorded (white arrow) with multiple echoessuggesting "separation of the leaflets" in the second recordedsystole. The AL and PL apparently meet at the C-point(black arrow) and move posterior to this point during theinitial half of systole. Multiple systolic clicks were consis-tently recorded (and heard) in this patient. Angiocardiogramshowed valve prolapse without mitral regurgitation. The leftatrium is recorded posterior to the valve echoes.

Circulation, Volume XLIX, March 1974

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Figure 6Left ventricular angiocardiogram, right anterior obliquieprojection. Left, early systolic frame, mitral valve is closed.Right, late systolic frame showing more posterior inferior)o.sition of rnitral valve shadow characteristic of mnitralvalve prolapse. Note the apparent increase in the extent ofprolapse duiring systole. (This patient hlad aortic root dila-tion as well.)

may be biphasic, forming a midsystolic notch, ormonophasic, which is described here as showingposterior motion for a prolonged period (>0.05sec) but beginning with the onset of systole. Sincethe usuial cyclic changes in ventricular volume stilloccur during systole, the pattern seen in all of thesecases is one of end-systolic motion towards thechest wall before the valves move to their openpositions. This suggests that the leaflets reach theirmost posterior position much later in systole thanis niormally seen, but after they cease their prolapsetoward the left atrium, the ongoing annulus motiontoward the chest wall is apparent.With amyl nitrite administration, the midsystolic

notch occurs earlier in the cycle, appearing verysimilar to the early systolic prolapse which is re-ported here as the second echographic patterni asso-ciated with the angiocardiographic abnoirnality.Sinice both patterns have been seen in the same pa-tient, it is felt that the echogram is recording twoforms of the same basic abnormality (fig. 7). Asthere is posterior motion of the leaflets after closture(C poinlt) in some normal patients, it is proposedthat the duration of this posterior motion is im-portanit for the proper diagnosis of prolapsing leaf-lets. This suggestion is supported by angiocardio-graphic observationi of a prolonged "rolling" or"'inflation" of the redunidant leaflets during the earlyphases of systole. It is this temporal prolongationof posterior motion during systole, as well as theamplitude of the posterior motion toward the atri-tum, which distinguishes these patients by echocar-diography (fig. 6).

This posterior motion during systole leads to anabnormally high opening excursion of the anteriorleaflet, which previously has been cited as an echo-Circulation, Volune XLIX, March 1974

Figure 7Simtultaneous pulmonary area (PA) and apex phonocardio-gram (PHONO), lead II electrocardiogram (EKG) apex-cardiogram (ACG) and mitral valve (MV) echocardiogramfrom a patient with spontaneous premature ectopic beats.Note the midsystolic notch and mid-late systolic murmurinl the sinus complexes. The early beat (third beat) showsearly systolic posterior motion and a full length systolicmturmur. (The apexcardiogram is technically poor.)

graphic criterion for mitral regurgitation.6 Whilethis fiuiding is associated with mitral valve prolapse,it does not indicate mitral regurgitation in all cases,as shown in this series. The early systolic prolapsepattern is commonly associated with a pansystolicmurmur of mitral regurgitation, but it may be pres-ent in association with multiple systolic clicks(fig. 5), and in several patients not studied by an-giocardiography this waveform has beeni associatedwith variable auscultatory findings in this labora-tory. Apparent separation of anterior and posteriorleaflet echoes may be recorded without ausculta-tory (fig. 3) or angiocardiographic findings of mi-tral regurgitation.

Since the mitral valve leaflets are not perfectlysmooth and the sound beam is relatively broad, itis possible to get discrete echoes from multipleareas of the same leaflet. This is seen very common-ly in normal patients and can be confirmed on stripchart records showing a low amplitude mitral wave-form which originates from the valve near the areaof the mitral annulus, as well as a higher ampli-tude waveform which originates near the free edgeof the valve undergoing the greater excursion(fig. 8). When the anterior mitral leaflet is tangen-tial to the relatively broad sound beam, separateparts of the leaflet will appear to be at differentdepths from the transducer anid give the appear-anlce of separate structures. It is suiggested that theredundancy and interchordal "hooding" wvhich iscommonly seen in surgical and autopsy specimensleads to multiple echoes in such a valve (fig. 9).7These multiple cuived surfaces will reflect sounldback to the transducer from multiple depths re-

431



POPP ET AL.

Figure 8

Echographic strip chart recording of the left ventricularoutflow tract obtained by slowly rocking the transducer fromone point on the chest wall. The beam is swept (left toright) from the body of the left ventricle (LV), below themitral valve leaflets, denoted by recording echoes fromchordae tendineae (c), to the area of the aorta (AO), withits intraluminal cusps and left atrium (LA) posterior to it.Note the relatively intense anterior mitral echo (white ar-

row) which is first recorded near the aortic root. A similarwaveform is seen in the less intense but higher amplitudeanterior mitral echoes which are first recorded further fromthe aortic root. The C-point is denoted by the black arrow.This patient had coronary artery disease but did not havevalve prolapse on the angiogram. P = pericardium, ECGelectrocardiogram.

gardless of their orientation to the sound beam.Therefore, multiple parallel echoes may be seen

on the echocardiogram, but this does not necessarilyrepresent separation of the leaflets. In addition,since chordae tendineae from each papillary mus-

cle insert into both the anterior and posterior leaf-lets, it would be very difficult for one leaflet toseparate from the other unless the chordae ten-dineae have become detached or extremely elon-gated, so that one leaflet may "overshoot" the other.7It may be these abnormal surfaces (hooding) thatlead to abnormal coaptation of the anterior andposterior leaflets, resulting in mitral regurgitation.Elongated chordae tendineae may permit the pos-

terior leaflet to move toward the atrium and de-4z .sFigure 9

Autopsy specimen of the mitral valve in a patient with themidsystolic click-late systolic murmur syndrome. Note thethickness and redundancy of the leaflets and the resultantinterchordal "hoods' (arrows). Both anterior and posteriorleaflets are involved.

crease the surface area in contact with the anteriorleaflet, but actual separation of the anterior andposterior leaflets during systole, in a way whichwould allow recognition with the ultrasound tech-nique, seems distinctly unlikely. Since the anteriorleaflet abuts the posterior leaflet during systole, itis expected that anterior or posterior leaflet pro-lapse will give an abnormal echographic waveformfrom both leaflets. It is extremely uncommon tofind only the anterior leaflet or only the posteriorleaflet involved in pathologic specimens, as theabnormal process does not stop at the commissuresof the valve.The echographic pattern of a midsystolic notch

is striking and quite easy to recognize. The onlypoint of confusion here could be with the echo-graphic pattern of idiopathic hypertrophic sub-aortic stenosis (IHSS) .r1 In a few cases theinitial systolic motion of the mitral valve in the pro-lapse syndrome may be slightly anterior, and incombination with the midsystolic notch it simulatesthe midsystolic anterior motion associated withIHSS. However, the late systolic position of themitral valve in the prolapse syndrome is posteriorto the C point, while in IHSS the end-systolic posi-tion is anterior to the C point. It has been shownthat amyl nitrite administration will move the posi-tioni of the midsystolic notch earlier in systole," andadministration of this substance can resolve anyquestion regarding the presence of mitral valveprolapse versus IHSS.5 The abnormal "U-shaped"early systolic pattern may be simulated by themitral valve echogram of patients with very lowoutpuit states, such as that seen in cardiomyopathies.In some of these patients, there is so little changein volume during systole that the anterior migra-tion of the mitral valve may be nearly impercep-tible. An additional factor in these dilated hearts isthat decreasing left ventricular volume during sys-tolic ejection allows the stretched mitral valve leaf-lets to move toward the left atrium and simulatethe prolapse patterni. However, it is a posterior mo-tion of the leaflets after the C point which is thehallmark of this abnormal pattern associated withprolapse.

So far, we have not seen the echographic patternof prolapse without angiographic or anatomic find-ings of this condition when such correlationis havebeen available. Because of technical factors, it maybe possible to miss the diagnosis of prolapse echo-cardiographically when it is present anatomically.However, the recognition of the early systolic pro-lapse reported here should decrease such false-neg-


432




ative results. It is interesting to note that echoesfrom both anterior and posterior mitral valve leaf-lets could be recorded clearly in six patients withthe sound beam directed up through the valve areaand into the left atrium (fig. 2). This suggests thatsuch valves do seat more toward the left atriumthan is the normal case, since simultaneous recordsof the posterior leaflet and left atrium are quiteunusual in other groups of patients (fig. 1). How-ever, due to the normal anterior systolic motionof the left ventricular posterior wall, it may bedifficult to recognize the posterior systolic motionof the mitral valve on the echogram if the soundbeam records these two structures simultaneously.For this reason it is suggested that the transducerbe placed lower than the usual position on thechest wall, so that the sound beam will pass upthrough the mitral valve structures and into theatrium.

This study demonstrates that the echographic ab-normality correlates with the angiocardiographicand anatomic abnormalities of the mitral valve pro-lapse syndrome. This correlation is found in theabsolute or temporary absence of phonocardio-graphic abnormalities. Because of the variable clin-ical presentation of patients with this syndrome,the constancy of the echographic abnormality maybe an important diagnostic feature. The syndromeincludes electrocardiographic abnormalities,8 9 atri-al and ventricular arrhythmias,9' 11 chest pain whichmay be quite severe in nature,8" 9 as well as variableauscultatory features.9' 12 While it cannot be statedfrom this study that the mitral valve abnormalityis the primary underlying factor in all of thesecases, we have seen echographic prolapse in pa-tients presenting with only arrhythmia or onlychest pain (wvith normal coronary arteriograms),as well as the suggestive auscultatory features. Be-cause of the recent evidence that propranolol maybe the treatment of choice for the arrhythmias as-sociated with this condition, it is important torecognize the association of the prolapse syndromewith the patient's arrhythmia.10' 11 The echographicpattern of prolapse is frequently found in our lab-oratory, and since there is a high prevalence ofatherosclerosis in our population, chest pain in as-sociation with this echocardiographic abnormalitycertainly cannot rule out coronary artery disease.13

With this noninvasive tool, it may be possible todiagnose mitral valve prolapse before it becomesclinically apparent in patients with minimal auscul-tatory or clinical findings, so that recommendationsregarding antibiotic prophylaxis and possible anti-arrhythmic prophylaxis may be made. In addition,now it should be possible to recognize the true inci-dence and follow the natural history of this con-dition in order to learn more about the variousaspects of the whole syndrome.

References1. SHAH PM, CRAMIAK R: Echocardiographic recognition

of mitral valve prolapse. (abstr) Circulation 42:III-45, 1970

2. KERBER RE, ISAEFF DM, HANCOCK EW: Echocardio-graphic patterns in patients with the syndrome ofsystolic click and late systolic murmur. N Engl JMed 284: 691, 1971

3. DILLON JC, HAINE CL, CHANG S, FEIGENBAUM H: Useof echocardiography in patients with prolapsed mitralvalve. Circulation 43: 503, 1971

4. ZAKY A, NASSER WK, FEIGENBAUM H. Study of mitralvalve action recorded by reflected ultrasound andits application in the diagnosis of mitral stenosis.Circulation 37: 789, 1968

5. PopP RL, HAmISON DC: Ultrasound in the diagnosisand evaluation of therapy of idiopathic hypertrophicsubaortic stenosis. Circulation 40: 905, 1969

6. SEGAL BL, LIKOFF W, KINGSLEY B: Echocardiography:Clinical application in mitral regurgitation. Am JCardiol 19: 50, 1967

7. EDWARDS JE: Mitral insufficiency resulting from "over-shooting" of leaflets. Circulation 43: 606, 1971

8. BARLOW JB, BOSMAN CK: Aneurysmal protrusion ofthe posterior leaflet of the mitral valve: An ausculta-tory-electrocardiographic syndrome. Am Heart J 71:166, 1966

9. HANCOCK EW, COHN K: The syndrome associated withmidsystolic click and late systolic murmur. Am J Med41: 183, 1966

10. BARLOW JB, PocociK WA: The effort electrocardiogramin the billowing posterior mitral leaflet syndrome.(abstr) Circulation 40: (Suppl III) III-40, 1969

11. ZEILENGA DW, CRILEY JM: Mitral valve dysfunction-a possible cause of arrhythmias in the prolapsedposterior leaflet syndrome. (abstr) Clin Res 21: 243,1973

12. FONTANA ME, PENCE HL, LEIGHTON RF, WOOLEY CF:The varying clinical spectrum of the systolic click-late systolic murmur syndrome. A postural ausculta-tory phenomenon. Circulation 41: 807, 1970

13. CHENG TO: Characterization of late systolic murmurassociated with coronary artery disease (abstr) Circu-lation 44: (Suppl II) II-31, 1971


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HARRISONRICHARD L. POPP, OWEN R. BROWN, JAMES F. SILVERMAN and DONALD C.

Echocardiographic Abnormalities in the Mitral Valve Prolapse Syndrome

Print ISSN: 0009-7322. Online ISSN: 1524-4539 Copyright © 1974 American Heart Association, Inc. All rights reserved.

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echocardiographic abnormalities in the mitral valve prolapse syndrome

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