The Congenital Isolated Apical Ventricular Septal Defect

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516 EXPERIENCE AND REASON

The

Congenital

Isolated

Apical

Ventricular

Septal

Defect

The differential diagnosis of a systolic murmur

heard mainly over the lower precordium in an

ap-parently well infant, child, or adolescent, is a common

pediatric problem. A ventricular septal defect (VSD)

is the most frequent pathologic condition in this

set-ting, and it usually produces a typical murmur that is

readily recognized. Some VSDS, however, are

asso-ciated with atypical murmurs due to their size and/or

location. Today, with two-dimensional

echocardiog-raphy (2D echo), Doppler measurement, and

espo-cially color-flow Doppler (CFD) imaging, we can

as-certain noninvasively the presence, location, and size

of a VSD and then correlate this information with the

type of murmur heard. This can enhance the

diag-nostic value of auscultation and consequently, in

some cases, eliminate the need for an

echocardio-gram.

To our knowledge, this report is the first to focus

specifically on the congenital isolated apicalVSD, and

it is largely the result of what we have learned from

the echocardiogram. Our purpose is to describe the

auscultatory and echocardiographic findings in a

so-ries of 16 patients with these defects, to review the

pertinent literature, and to discuss the diagnosis,

natural history, and management of this entity.

CASE REPORTS

Sixteen patients, referred by pediatricians for evaluation of a systolic murmur and examined by one of the authors (S.O.S.), during a 15-month period, beginning October 1991, were identi-fled by 2-D echo with CR) imaging as having a single small defect in the apical portion of the ventricular septum. The first two patients were seen at the UCLA Medical Center, the others at the Panorama City and Woodland Hills Kaiser Permanente Medical Centers in Los Angeles. At the time of echocardiographic

diagno-sis, the age range was 2 days to 18 years. Six patients were <1 year of age, eight were between 20 months and 8 years, one was 14 years and one 18 years of age. Nine were females. All were asymp-tomatic, with normal growth and development and normal chest radiographs and electrocardiograms.

On physical examination, the cardiac findings were normal except for the presence of a typical systolic murmur with the following characteristics: grade 2-3/6 intensity; short duration, peaking in early to midsystole; medium to high pitch; noisy qual-ity (shrill, harsh, nonmusical, nonvibratory); best heard at the apex or doser to the apex than the left sternal border; well localized. In all cases CFD imaging revealed a narrow, short, colored jet pass-ing through the septum from left to right ventride at the apex of the heart, distal to the moderator band (Figure). The jet was de-tected most often in a four-chamber view (apical, supracostal, or subcostal), less frequently in the parasternal long axis view, and in only one patient in the parasternal short axis view. The defects were difficult to image and required specific angulation of the transducer and thorough exploration of the distal ventricular sep-him. Pulsed and continuous wave Doppler interrogation identi-fled an increased systolic flow velocity (>2 m/s) in only seven patients. Using these velocities, peak instantaneous systolic pres-sure gradients across the defects were calculated and ranged from

Received for publication Apr 12, 1993; accepted Aug 18, 1993.

Reprint requests to (S. 0. S.) Dept of Pediatrics, Southern California Per-manente Medical Group, 13652 Cantara St. Panorama City, CA 91402. PEDIATRICS (ISSN 0031 4005). Copyright © 1994 by the American

Acad-amy of Pediatrics.

16 to 81 mm Hg. Of the four infants who had follow-up exami-nations, there was spontaneous closure of the defect in three, as judged by the disappearance of the murmur, by 5 months of age.

DISCUSSION

The VSD is the most common type of congenital

heart lesion. The defect in the septum may be in its

inlet portion (near the atrioventricular valves), the

midportion (muscular or trabecular septum), or the

outflow portion (just below the semilunar valves).

Likewise, defects within the muscular septum can be

at the apex, the midportion or the outflow area.

Oc-casionally there can be more than one type of VSD.

Also, multiple detects within the muscular septum

may be found. Most VSDS are associated with the

so-called maladio-do-Roger type murmur which has the

following characteristics: loud, at least grade 3/6 in

intensity, often with a thrill; long in duration

(holo-systolic); very noisy quality (harsh, rough, sawing,

rasping); best heard over the mid to lower sternum or

the adjacentleft sternal border; well transmitted to the

rest of the precordium. This murmur is produced by

turbulent blood flow, with varying flow velocities,

from left to right ventricle through the defect. Very

large defects and those with increased pulmonary

vascular resistance may have lower velocity and less

turbulent flow and consequently less prominent

mur-murs. Very small defects may also have atypical

mur-murs. The type of murmur associated specifically

with a small apical VSD has heretofore received scant

mention in the literature.

In 1960 Evans et al’ described 37 children with

spontaneous closure of VSDs. As the left-to-right

shunts decreased, the murmurs became shorter and

disappeared completely by 10 years of age. The

au-thors postulated that septal growth gradually

pinched off the defect, shortening the duration of the

murmur during systole and eventually causing it to

disappear when the defect closed completely. Of nine

other patients with incomplete closure, four had

api-cal VSDS, as determined by intracardiac

phonocardi-ography and/or left ventricular angiography but

their auscultatory characteristics were not specifically

described. Vogelpoelet al,2 in 1961, described atypical

murmurs with VSDs diagnosed by intracardiac

pho-nocardiography. The murmurs were noted to be

short, medium to high pitch, heard only in midsystole

and loudest at the mid to lower left sternal border. In

one patient the defect was thought to be in the apical

portion of the ventricular septum because the

intra-cardiac murmur was loudest in the apex of the right

ventricle. Interestingly, the murmur recorded over

the precordium was loudest at the “mitral area” and

the author states, “The possibility of a low minute

septal defect must be considered when an apical

systolic murmur exhibits an early

crescendo-decrescendo pattern.” Saab et a13 noted two apical

VSDs in 23 patients with isolated muscular VSDs who

had surgical repair, but the murmurs were not

de-scribed. More recently, Kapusta et al4 reported the

echocardiographic findings in 60 patients with

iso-lated VSDS diagnosed clinically. Four had apical

VSDs, with three of these having early-midsystolic,

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VSD JET

EXPERIENCE AND REASON 517

Figure. Two-dimensional

echocar-diogram with color-flow Doppler

im-aging in a 4#{189}-month-old girl. An angled, apical four-chamber view demonstrates a narrow, short, colored

jet, in early systole, passing from left to right ventricle through a small

yen-tricular septal defect at the apex of the heart. The peak flow velocity of the jet, obtained with Doppler, predicts an

in-stantaneous peak systolic pressure gra-dient of 50 mm Hg across the defect. LV, left ventricle; RV, right ventricle; VSD, ventricular septal defect.

high-frequency murmurs. The maximal location of

the murmurs was not noted. In a recent Japanese

re-port, 2-D echo with CFD imaging was obtained in a

series of 1028 normal-appearing term newborns.5

De-fects in the trabecular (muscular) portion of the

yen-tricular septum were identified in 21 (2%). This group

was combined with 25 other newborns who also had

trabecular defects. Eleven of these 46 infants had

api-cal septal VSDs. Some of the 46 infants had short

mur-murs, but the type of murmur in those with apical

defects was not mentioned. A review of the

descrip-tion ofVSD murmurs in several current texts discloses

statements that muscular septal defects or small

de-fects may produce short, high-frequency murmurs

but only one6 notes that the murmur from a low

mus-cular defect may be heard between the lower left

ster-nal border and the apex.

The findings in our 16 cases confirm the

sugges-tions in the literature that an apical VSD produces a

distinctive type of systolic murmur in a particular

10-cation. In our first two cases, this association was

sus-pected in retrospect, after the echocardiogram

iden-tified an apical VSD. In all the subsequent cases,

however, the auscultatory findings correctly

pre-dicted the presence of an apical VSD before it was

seen in the echocardiogram. We are further convinced

of the diagnostic specificity of this murmur because

we have not heard it in patients with nonapical VSDs,

diagnosed by echocardiography, and because of the

descriptions of VSD murmurs in the literature. There

is no published information available regarding the

diagnostic sensitivity of this murmur, and the method

for selecting our patients does not permit us to make

any statement regarding the sensitivity of the clinical

examination in detecting an apical VSD. Although

distinctive, the murmur most closely resembles and

must be distinguished from the normal Still’s

precor-dial vibratory murmur. Both murmurs are usually

grade 3 or less in intensity, short in duration, and best

heard at, or closer to the apex than the left sternal

border. The critical differentiating features are the

quality and pitch: Still’s murmur is musical (vibratory,

groaning, humming, twanging string) and low to

mo-dium in pitch; the apical VSD murmur is noisy (shrill,

harsh) and medium to high in pitch. A small,

non-apical VSD may also produce a short, noisy, medium

to high pitch systolic murmur but it differs from the

apical VSD murmur in that it is heard best over the

mid to lower precordium or the adjacent left sternal

border rather than at or closer to the apex.

In our perhaps controversial opinion, when a

typi-cal apical VSD murmur is heard, in an otherwise

healthy appearing patient, an echocardiogram is not

indicated for confirmation of the diagnosis because,

even with CFD imaging, one may fail to identify a

small defect. In three of our cases, a previous 2-D echo

with CFD imaging did not find the apical VSD. Also,

in our most recent case, a 4-year-old, because of the

strong auscultatory impression that there was an

api-cal VSD, three echocardiograms were obtained before

the small defect was finally seen with CFD imaging.

Doppler measurement was too insensitive overall

in our cases to be useful in diagnosis. The small size

of the jet, coupled with patient, respiratory, and

car-diac movement would explain the inability to find

any VSD gradient in some cases and an obviously

falsely low value in others. Other authors have

re-ported a similar experience. Using pulsed Doppler

without CFD imaging, Stevenson et al7 reported a

di-agnostic sensitivity of 90% for VSDs identified by

an-giocardiography, with one apical VSD being missed.

With CFD imaging, Kapusta et al4 found a sensitivity

of 95% in 60 patients with clinically diagnosed small

VSDs. They stressed, as we have, the importance of an

experienced sonographer and appropriate machine

settings to visualize small jets with CFD imaging,

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518 EXPERIENCE AND REASON

pecially defects in the muscular and apical portion of

the ventricular septum. Wippermann and Schranz8

reported the diagnostic sensitivity ofCFD imaging for

VSDS to be 94.5% to 98.3% and conduded, “In our

opinion, auscultation is more sensitive in detecting a

small VSD and moreover a small VSD cannot be

ex-cluded by color-flow imaging.” Conversely, Linker et

al9 reported on two patients without VSDs, by clinical

examination, who were diagnosed erroneously as

having muscular septal defects by CFD imaging.

Cer-tainly, with less experienced sonographers, 2-D echo

with CFD imaging will have even less diagnostic

sen-sitivity, and perhaps specificity, than noted above.

Diagnosing even a small VSD is important because

of the risk of infectious endocarditis and the

advis-abffity of antibiotic prophylaxis. Although it was

stated years ago that small VSDs may be less

suscep-tible to infectious endocarditis,3 we have not found

this view corroborated in subsequent reports.

Thero-fore, in our opinion, patients who have the typical

auscultatory findings of an isolated apical VSD

should be counseled, without a confirmatory

echocar-diogram, to receive prophylactic antibiotics when

ap-propriate. On the other hand, if one cannot be certain

from auscultation that the patient has either a normal

Still’s systolic precordial vibratory murmur, or a

typi-cal small VSD murmur, or if one suspects an

associ-ated lesion, then it would be appropriate at some

point to obtain a 2-D echo with Doppler and CFD

imaging to establish the diagnosis. Other pathologic

entities which can produce a systolic murmur over the

mid to lower precordium include a moderate- to

largo-size VSD, infundibular stenosis, subaortic or

aortic stenosis, mitral regurgitation, and tricuspid ro-gurgitation.

If the diagnosis of an apical VSD is made, an

ex-cellent prognosis can be given. The main risk is that

of infectious endocarditis, and this will probably be

decreased by the appropriate use of antibiotic

pro-phylaxis. In infancy, there is also a good likelihood of

spontaneous closure. This occurred in three of our

infants, as noted. Hiraishi et a15 reported that in 76%

of the 42 infants with trabecular VSDs followed up

with CFD imaging, the VSD dosed by 12 months of

age. In his 11 infants with apical VSDS, the dosure rate

was less, 45%, but still relatively high. Hornberger et

al’#{176}noted that in four infants with apical VSDs, two

of the apical defects became smaller in the first year

of life. However, even if the defect does not close,

most patients with isolated apical VSDS will remain

asymptomatic and not require treatment. The defect

may rarely be large, but these patients wifi have a

different clinical examination and may develop

con-gestive heart failure”10”1 or pulmonary vascular

dis-ease and require surgery.3”2

CONCLUSION

Congenital isolated apical VSDS can be found from

early infancy through adolescence. Spontaneous

do-sure is common in the first year of life. The defects are

almost always small and rarely cause symptoms or

require surgery. Antibiotic prophylaxis for infectious

endocarditis is indicated. The auscultatory findings

are characteristic and distinctive, and when present,

referral for an echocardiogram or to a pediatric

car-diologist is not necessary. The most cost-effective

ap-proach to the diagnosis is the use of the stethoscope

and an educated ear.

SAMUEL 0. SAPIN, MD

Dept of Pediatrics

Southern California Permanente Medical Group

Panorama City, CA

Dept of Pediatrics

Division of Cardiology

UCLA School of Medicine

PAUL A. JUNKEL

Department of Cardiac Sonography

Kaiser Permanente Medical Center

Panorama City, CA

Mi LmrWONG, RDMS

KAREN C. Sirir, RDMS

Department of Cardiac Sonography

UCLA Medical Center

REFERENCES

1. EvansJR, Rowe MB, KeithJD. Spontaneous closure ofventricular septal

defects. Circulation. 1960;22:1044-1054

2. Vogelpoel MD, Schrire V, BeckW, Nellen M, Swanepoel A. The atypical systolic murmur of minute ventricular septal defect and its recognition

by amyl nitrite and phenylephrine. Am Heart J.1%162:101-118 3. Saab NG, Burchell Fifi, DuShane JW, Titus JL. Muscular ventricular

septal defects. Am ICardiol. 1966;18:713-723

4. Kapusta L, HopmanJCW, Daniels 0. The usefulness ofcross-sectional

Doppler flow imaging in the detection of small ventricular septal de-fects with left-to-right shunt. Eur Heart I.19878:1002-1006

5. Hiraishi 5, Agata Y,Nowatari M, at aL Incidence and natural course of trabecular ventricular septal defet± two-dimensional echocardiography

and color Doppler flow imaging study. IPediatr. 1992;120:409-415 6. MollerJH, Neal WA. Fetal, Neonatal and Infant Cardiac Disease. Norwalk,

a: Appleton and Lange; 1990:376

7. Stevenson JG, Kawabori I, Dooley T, Guntheroth WG. Diagnosis of ventricular septal defect by pulsed Doppler echocardiography: sensi-tivity, spedficity and limitations. Circulation. 197858:322-326

8. Wipperman F, Schranz D. Colour-flow mapping in patients with yen-tricular septal defect. Eur IPediatr. 1991;150:527

9. Linker DT, Rossvol 0, Chapman JV, Angelsen BAJ. Sensitivity and

speed of colour Doppler flow mapping compared with continuous

wave Doppler for the detection of ventricular septal defects. Br Heart I.

1991;65:201-203

10. Hornberger LK, Sahn DJ, Krabill KA, et al. Elucidation of the natural history of ventricular septal defects by serial Doppler color flow map-ping studies. IAm Coll Cardiol. 1989;13:1111-1118

11. Mehta AV, chidambaram B. Ventricular septal defect in the first year of life. Am ICardiol. 1992;70:364-366

12. Heath D, Brown JW, Whitaker W. Muscular defects in the ventricular system. Br Heart I.1956;18:1-7

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1994;93;516

Pediatrics

Samuel O. Sapin, Paul A. Junkel, Ah Lin Wong and Karen G. Simandle