This document discusses pulmonary stenosis (PS), a congenital heart defect where the pulmonary valve is narrowed. It accounts for 20-30% of congenital heart disease. PS can be valvular, subvalvular, or supravalvular. Symptoms range from none to right heart failure. Diagnosis involves listening for a systolic murmur and click, and imaging like echocardiogram and catheterization to measure pressures and gradients. Treatment is usually balloon valvuloplasty or surgery if severe.

1. FuadFuad
FarooqFarooq

2.  Pulmonary Stenosis (PS) has beenPulmonary Stenosis (PS) has been
described in 1761 by Morgagnidescribed in 1761 by Morgagni
 It accounts for 20-30% of all CHDIt accounts for 20-30% of all CHD
 Found in 8% to 10% of patients as isolatedFound in 8% to 10% of patients as isolated
PSPS
 In 50% of cases the septum is intactIn 50% of cases the septum is intact

3. Three anatomical varientsThree anatomical varients
 Valvar (90%)Valvar (90%)
 Subvalvar (Subvalvar (Infundibular stenosisInfundibular stenosis
from hypertrophy of the Cristafrom hypertrophy of the Crista
Supraventricularis)Supraventricularis)
 Supravalvar (pulmonary artery trunkSupravalvar (pulmonary artery trunk
or branches )or branches )

4. Pulmonary valve stenosis is usuallyPulmonary valve stenosis is usually
isolated or part of the complex congenitalisolated or part of the complex congenital
heart diseaseheart disease

5.  Exact embryologic process is not wellExact embryologic process is not well
understoodunderstood
 Mal-development of the distal part of the bulbusMal-development of the distal part of the bulbus
cordiscordis
 Genetic factors may play a roleGenetic factors may play a role
 Known association between pulmonary valve andKnown association between pulmonary valve and
supravalvular stenosis with multiple somaticsupravalvular stenosis with multiple somatic
abnormalitiesabnormalities

6.  Valve commisures are partially fused and the 3Valve commisures are partially fused and the 3
leaflets are thin and pliant, resulting in a conicalleaflets are thin and pliant, resulting in a conical
or dome-shaped structure with a narrowedor dome-shaped structure with a narrowed
central orificecentral orifice
 It may be diffusely thickened with one, two, orIt may be diffusely thickened with one, two, or
three leaflets and commissural fusionthree leaflets and commissural fusion

7. Bicuspid valve is found in 90% of patientsBicuspid valve is found in 90% of patients
with Tetralogy of Fallotwith Tetralogy of Fallot
 Rare in individuals with isolated valvular PSRare in individuals with isolated valvular PS

8. 10-15% of individuals with valvular PS have10-15% of individuals with valvular PS have
dysplastic pulmonary valvesdysplastic pulmonary valves
 Valves have irregularly shaped, thickenedValves have irregularly shaped, thickened
leaflets, with little commissural fusion and exhibitleaflets, with little commissural fusion and exhibit
reduced mobilityreduced mobility
 The leaflets are composed of myxomatous tissue,The leaflets are composed of myxomatous tissue,
which may extend to the vessel wallwhich may extend to the vessel wall
 The valve annulus is usually small and theThe valve annulus is usually small and the
supravalvular area of the pulmonary trunk issupravalvular area of the pulmonary trunk is
usually hypoplasticusually hypoplastic
 Poststenotic dilatation of the pulmonary artery isPoststenotic dilatation of the pulmonary artery is
uncommonuncommon

9.  Secondary changes in the right ventricle andSecondary changes in the right ventricle and
pulmonary arteriespulmonary arteries
 Right ventricle espacially infundibular regionRight ventricle espacially infundibular region
becomes diffusely hypertrophiedbecomes diffusely hypertrophied
 Produce dynamic subvalvular obstructionProduce dynamic subvalvular obstruction
 Right atrium may be thick and dilate as aRight atrium may be thick and dilate as a
result of the increased pressure necessaryresult of the increased pressure necessary
to fill the hypertrophic right ventricleto fill the hypertrophic right ventricle

10.  Rise in RV pressure proportional to theRise in RV pressure proportional to the
severity of obstructionseverity of obstruction
 Increase in muscle massIncrease in muscle mass
 Hyperplasia of the muscle cells with aHyperplasia of the muscle cells with a
concomitant increase in the number of capillariesconcomitant increase in the number of capillaries
 Increased muscle mass may enable theIncreased muscle mass may enable the
hypertensive right ventricle to maintain ahypertensive right ventricle to maintain a
normal stroke volumenormal stroke volume

11.  Development of poststenotic dilation ofDevelopment of poststenotic dilation of
the pulmonary artery trunk sometimesthe pulmonary artery trunk sometimes
extending to the proximal left pulmonaryextending to the proximal left pulmonary
arteryartery
 Result from the high velocity jet of flow ejectedResult from the high velocity jet of flow ejected
through the small valve orifice - “jet effect”through the small valve orifice - “jet effect”
 The degree of dilation is not necessarilyThe degree of dilation is not necessarily
proportional to the severity of obstructionproportional to the severity of obstruction

12. RV eventually dilate and failRV eventually dilate and fail
Exacerbated by:Exacerbated by:
 Development of tricuspid insufficiencyDevelopment of tricuspid insufficiency
 Subendocardial (esp. at infundibular region) andSubendocardial (esp. at infundibular region) and
papillary muscle ischemia/infarctionpapillary muscle ischemia/infarction

13.  Mostly diagnosis is made when murmurMostly diagnosis is made when murmur
detected in asymptomatic patients on routinedetected in asymptomatic patients on routine
examinationexamination
 Exertional dyspnea, fatigue and cynosis dueExertional dyspnea, fatigue and cynosis due
to inability of the right ventricle to increase itsto inability of the right ventricle to increase its
output in response to exertionoutput in response to exertion
 If the stenosis is not relieved then features ofIf the stenosis is not relieved then features of
right heart failureright heart failure

14. Chest pain, syncope and sudden deathChest pain, syncope and sudden death
with strenuous exercisewith strenuous exercise
Decreased myocardial perfusion caused byDecreased myocardial perfusion caused by
inadequate cardiac output during exercise,inadequate cardiac output during exercise,
leading to ischemia and ventricular arrhythmiasleading to ischemia and ventricular arrhythmias

15. ‘‘a’ wave becomes progressively largera’ wave becomes progressively larger
with increasing severity of obstructionwith increasing severity of obstruction

16.  Left parasternal heaveLeft parasternal heave
 Systolic thrill in severe pulmonarySystolic thrill in severe pulmonary
stenosisstenosis
 Located at the 2Located at the 2ndnd
to 3to 3rdrd
intercostal space butintercostal space but
it may also be felt at the suprasternal notchit may also be felt at the suprasternal notch
 Absent in young infants with severe stenosisAbsent in young infants with severe stenosis
and in patients with congestive heart failureand in patients with congestive heart failure
and low cardiac outputand low cardiac output

17. S1 normal followed by a pulmonaryS1 normal followed by a pulmonary
ejection click in patients with mild orejection click in patients with mild or
moderate stenosismoderate stenosis
 Corresponds to the time when the domingCorresponds to the time when the doming
pulmonary valve reaches its open positionpulmonary valve reaches its open position
 Become earlier as severity increased until itBecome earlier as severity increased until it
merges with the first heart sound andmerges with the first heart sound and
becomes inaudiblebecomes inaudible

18. Click is followed by ESM maximal at theClick is followed by ESM maximal at the
upper left sternal borderupper left sternal border
Intensity – increases with the severity of obstructionIntensity – increases with the severity of obstruction
Radiation – entire precordium, neck & backRadiation – entire precordium, neck & back
(characteristically)(characteristically)
Become soft when severe stenosis with right heartBecome soft when severe stenosis with right heart
failure due to low cardiac outputfailure due to low cardiac output

19. P2 intensity typically decreases withP2 intensity typically decreases with
increase severity of obstructionincrease severity of obstruction

20.  S4 – lower left sternal border in patients withS4 – lower left sternal border in patients with
severe stenosissevere stenosis
 Pansystolic murmur of tricuspid insufficiencyPansystolic murmur of tricuspid insufficiency
may be present lower along the left sternalmay be present lower along the left sternal
borderborder
 S3 – when present think of ASDS3 – when present think of ASD

23. Mild stenosis usually have a normalMild stenosis usually have a normal
electrocardiogramelectrocardiogram
Rightward axis deviation is often the only abnormalityRightward axis deviation is often the only abnormality

24. Electrocardiogram is almost alwaysElectrocardiogram is almost always
abnormalabnormal
 Right axis deviationRight axis deviation
 The R:S ratio in V1 is usually >4:1The R:S ratio in V1 is usually >4:1
 R wave is typically <20 mmR wave is typically <20 mm
 The T waves in the right precordial leads areThe T waves in the right precordial leads are
upright in approximately 50% of patientsupright in approximately 50% of patients

25.  QRS axis >110 degrees and not uncommonly extremeQRS axis >110 degrees and not uncommonly extreme
RADRAD
 A pure R, Rs, or QR is the usual pattern in the rightA pure R, Rs, or QR is the usual pattern in the right
precordial leads, and the R wave is usually >20 mmprecordial leads, and the R wave is usually >20 mm
 The R:S ratio in VThe R:S ratio in V66 may be <1.0may be <1.0
 The T waves usually inverted in the right precordial leadsThe T waves usually inverted in the right precordial leads
 P-pulmonale indicating right atrial enlargementP-pulmonale indicating right atrial enlargement

26. Estimation of RV pressure is possibe if a pure REstimation of RV pressure is possibe if a pure R
wave is present in lead Vwave is present in lead V4R4R or Vor V11
The height of the R wave in millimeters,The height of the R wave in millimeters,
multiplied by 5, approximates the rightmultiplied by 5, approximates the right
ventricular pressure in mm of Hgventricular pressure in mm of Hg

28.  Enlarged main pulmonary artery secondaryEnlarged main pulmonary artery secondary
to post-stenotic dilatationto post-stenotic dilatation
 Enlarged left pulmonary artery (jet streamEnlarged left pulmonary artery (jet stream
effect)effect)
 Normal to decreased peripheral pulmonaryNormal to decreased peripheral pulmonary
vasculaturevasculature
 CardiomegalyCardiomegaly
 Results from RA and RV enlargementResults from RA and RV enlargement

29.  Standard and high parasternal short and longStandard and high parasternal short and long
axis views and the subcostal sagittal viewsaxis views and the subcostal sagittal views
 Valve leaflets usually appear prominent becauseValve leaflets usually appear prominent because
of thickeningof thickening
 Systolic motion is restricted, with inward curvingSystolic motion is restricted, with inward curving
of the tips of the leaflets, known as domingof the tips of the leaflets, known as doming
 Poststenotic dilation of the main and branchPoststenotic dilation of the main and branch
pulmonary arteries are also easily recognizedpulmonary arteries are also easily recognized

33.  Assessment of RV anatomy and function andAssessment of RV anatomy and function and
assessment of tricuspid valveassessment of tricuspid valve
 Evidence of dynamic subpulmonary stenosisEvidence of dynamic subpulmonary stenosis
should be soughtshould be sought
 Dysplastic pulmonary valve usually can beDysplastic pulmonary valve usually can be
ascertained by echocardiographyascertained by echocardiography
 The leaflets appear thickened and immobile,The leaflets appear thickened and immobile,
without the characteristic doming seen in typicalwithout the characteristic doming seen in typical
casescases
 The pulmonary valve annulus is hypoplastic, andThe pulmonary valve annulus is hypoplastic, and
supra-annular narrowing of the proximal mainsupra-annular narrowing of the proximal main

34.  Allows quantitative assessment of severityAllows quantitative assessment of severity
of pulmonary valve stenosisof pulmonary valve stenosis
 The echo beam must be aligned parallelThe echo beam must be aligned parallel
with the main pulmonary artery trunk orwith the main pulmonary artery trunk or
the direction of the flow jet as seen onthe direction of the flow jet as seen on
color Dopplercolor Doppler
 Excellent correlation between the Doppler-Excellent correlation between the Doppler-
derived gradient and that obtained byderived gradient and that obtained by

35.  Role of catheterization has becomeRole of catheterization has become
largely limited in therapeuticslargely limited in therapeutics

36.  Measurement of RV pressure andMeasurement of RV pressure and
compared with systemic arterial pressurecompared with systemic arterial pressure
and the pressure gradient across theand the pressure gradient across the
pulmonary valvepulmonary valve
 Resting RV pressure >30 to 35 mm HgResting RV pressure >30 to 35 mm Hg
and pressure gradient across theand pressure gradient across the
pulmonary valve of >10 are consideredpulmonary valve of >10 are considered
abnormalabnormal

37. RV pressures 105 mmHg and PA pressures are 60, so the gradient is 45 mmHg

38.  If associated infundibular obstruction, pressureIf associated infundibular obstruction, pressure
gradients are encountered across the pulmonarygradients are encountered across the pulmonary
valve and also across the infundibulumvalve and also across the infundibulum
 RVEDP may be normal but usually elevated withRVEDP may be normal but usually elevated with
severe obstruction or right ventricular failuresevere obstruction or right ventricular failure
 Right atrial pressure is normal in mild toRight atrial pressure is normal in mild to
moderate obstruction, but tall right atrial ‘A’moderate obstruction, but tall right atrial ‘A’
waves usually are seen with severe obstructionwaves usually are seen with severe obstruction

39.  Provides information about the locationProvides information about the location
and severity of pulmonary stenosis that isand severity of pulmonary stenosis that is
invaluable for diagnostic and therapeuticinvaluable for diagnostic and therapeutic
purposespurposes
 Anatomy of the pulmonary valve andAnatomy of the pulmonary valve and
associated features can be shown best byassociated features can be shown best by
right ventricular angiography in theright ventricular angiography in the
anteroposterior cranial and lateral viewanteroposterior cranial and lateral view

40.  Normal pulmonary valve area is 2.0 cmNormal pulmonary valve area is 2.0 cm22
/m/m22
of BSAof BSA
Mild stenosis
- Valve area larger
than 1 cm2
- Right ventricular
pressure less than
half the left
ventricular
pressure
- Peak gradient
10-35 mm Hg
- Peak velocity
<3m/sec
Moderate stenosis
- Valve area 0.5-
1.0 cm2
- Right ventricular
pressure is greater
than half but <75%
of the left
ventricular
pressure
- Peak gradient is
36-64 mm Hg
- Peak velocity 3-
4m/sec
Severe stenosis
- Valve area <0.5cm2
-Right ventricular
pressure 75% of the left
ventricular pressure -
Peak gradient >64 mm
Hg
- Peak velocity >4/sec

41.  Idiopathic dilation of the main pulmonary arteryIdiopathic dilation of the main pulmonary artery
 ASDASD
 Peripheral pulmonary arterial stenosisPeripheral pulmonary arterial stenosis
 Mitral valve prolapseMitral valve prolapse
 Straight back syndromeStraight back syndrome
 Aortic stenosisAortic stenosis
 Innocent murmursInnocent murmurs
 VSD with or without associated pulmonaryVSD with or without associated pulmonary
stenosisstenosis
 Tetralogy of FallotTetralogy of Fallot
 Pulmonary atresia with intact ventricular septumPulmonary atresia with intact ventricular septum
 Ebstein anomaly of the tricuspid valveEbstein anomaly of the tricuspid valve

42.  Noonan syndrome in 50% of patientsNoonan syndrome in 50% of patients
 Most common lesion is pulmonary stenosis owing to pulmonaryMost common lesion is pulmonary stenosis owing to pulmonary
valve dysplasiavalve dysplasia
 25% of Hypertrophic CMP of the left ventricle with PS25% of Hypertrophic CMP of the left ventricle with PS
 Rarely - cardiac tumors can grow on or into the RVRarely - cardiac tumors can grow on or into the RV
outflow tract and cause flow obstructionoutflow tract and cause flow obstruction
 Extrinsic lesions e.g., Sinus of Valsalva aneurysms andExtrinsic lesions e.g., Sinus of Valsalva aneurysms and
aortic graft aneurysms compressing cardiac structuresaortic graft aneurysms compressing cardiac structures
and can cause PSand can cause PS
 Multiple lentigines syndrome, or leopard syndrome, hasMultiple lentigines syndrome, or leopard syndrome, has
been associated with pulmonary valve and pulmonarybeen associated with pulmonary valve and pulmonary
artery stenosisartery stenosis

43.  Neurofibromatosis, deposits from glycogen storageNeurofibromatosis, deposits from glycogen storage
diseases and goutdiseases and gout
 Carcinoid results in development of myxomatousCarcinoid results in development of myxomatous
(fibroelastic) plaques in the RV outflow tract(fibroelastic) plaques in the RV outflow tract
 Distortion and constriction of the pulmonic ring, as well as fusionDistortion and constriction of the pulmonic ring, as well as fusion
or destruction of pulmonary valve leaflets, resulting in bothor destruction of pulmonary valve leaflets, resulting in both
stenosis and regurgitationstenosis and regurgitation
 Rare manifestation of rheumatic heart disease - followsRare manifestation of rheumatic heart disease - follows
involvement of the mitral and aortic valvesinvolvement of the mitral and aortic valves

44.  Valvuloplasty should be performed in anyValvuloplasty should be performed in any
symptomatic patient as soon as thesymptomatic patient as soon as the
diagnosis is madediagnosis is made
 Immediate valvoplasty in infants withImmediate valvoplasty in infants with
critical pulmonary valve stenosiscritical pulmonary valve stenosis
 Asymptomatic patients with severeAsymptomatic patients with severe
obstruction should be treatedobstruction should be treated
semielectively with valvuloplasty shortlysemielectively with valvuloplasty shortly

45.  Moderate obstruction should undergoModerate obstruction should undergo
elective valvuloplasty if the rightelective valvuloplasty if the right
ventricular pressure is 50% systemic orventricular pressure is 50% systemic or
higherhigher
 No intervention is necessary for patientsNo intervention is necessary for patients
with mild obstructionwith mild obstruction
 They should not be restricted in their physicalThey should not be restricted in their physical
activity and should be treated as normalactivity and should be treated as normal
childrenchildren

46.  Described initially by Kan and associates inDescribed initially by Kan and associates in
19821982
 After obtaining appropriate hemodynamic andAfter obtaining appropriate hemodynamic and
angiographic information about severity andangiographic information about severity and
location of obstruction, an exchange guidewire islocation of obstruction, an exchange guidewire is
introduced through an end-hole catheter andintroduced through an end-hole catheter and
positioned in the distal left pulmonary arterypositioned in the distal left pulmonary artery
 A balloon is chosen that is 20% to 40% largerA balloon is chosen that is 20% to 40% larger
than the angiographically measured pulmonarythan the angiographically measured pulmonary
valve annulus, and it is positioned over avalve annulus, and it is positioned over a
guidewire with the valve at its midpointguidewire with the valve at its midpoint
 In larger patients with an annulus diameter ofIn larger patients with an annulus diameter of
>20 mm, the double-balloon technique may be>20 mm, the double-balloon technique may be

47.  Independent predictors of suboptimalIndependent predictors of suboptimal
intermediate-term outcomeintermediate-term outcome
 Small annular size (characteristic of patientsSmall annular size (characteristic of patients
with dysplastic valves)with dysplastic valves)
 Higher immediate residual gradientHigher immediate residual gradient
 Earlier year of the initial valvuloplastyEarlier year of the initial valvuloplasty
 Smaller balloon to annulus ratioSmaller balloon to annulus ratio

48.  Death (0.2%)Death (0.2%)
 Laceration of the inferior vena cava, iliac veinLaceration of the inferior vena cava, iliac vein
junction during balloon withdrawaljunction during balloon withdrawal
 Tearing of the pulmonary valve annulus duringTearing of the pulmonary valve annulus during
balloon inflationballoon inflation
 Perforation of the right ventricular outflowPerforation of the right ventricular outflow
tract resulting in tamponade and tricuspidtract resulting in tamponade and tricuspid
regurgitation requiring surgical interventionregurgitation requiring surgical intervention
 Vein thrombosis and vein tearsVein thrombosis and vein tears
 Arrhythmias (1.3%)Arrhythmias (1.3%)

49.  Stroke, seizures, necrotizing enterocolitis,Stroke, seizures, necrotizing enterocolitis,
endocarditis and septic shockendocarditis and septic shock
 Abrupt closure of the ductus despiteAbrupt closure of the ductus despite
prostaglandin infusion requiring urgentprostaglandin infusion requiring urgent
aortopulmonary shunt placementaortopulmonary shunt placement
 Pulmonary insufficiencyPulmonary insufficiency
 Risk factors: smaller body surface area at theRisk factors: smaller body surface area at the
time of intervention, larger balloon to annulustime of intervention, larger balloon to annulus
ratio and a higher degree of obstructionratio and a higher degree of obstruction
before dilationbefore dilation

50.  Reserved for dysplastic pulmonary valvesReserved for dysplastic pulmonary valves
resistant to dilation or with multiple levels ofresistant to dilation or with multiple levels of
fixed obstructionfixed obstruction
 Often a persistent pressure gradient immediatelyOften a persistent pressure gradient immediately
after surgery in patients with isolated valvarafter surgery in patients with isolated valvar
pulmonary stenosis attributable to dynamicpulmonary stenosis attributable to dynamic
narrowing of the hypertrophied infundibulum (asnarrowing of the hypertrophied infundibulum (as
also observed following balloon valvuloplasty)also observed following balloon valvuloplasty)
 Reduction in gradient occur in the first 24 hoursReduction in gradient occur in the first 24 hours
after surgery and continues at a slower rate asafter surgery and continues at a slower rate as
the hypertrophy resolves over the subsequentthe hypertrophy resolves over the subsequent

51.  Presence of symptoms such asPresence of symptoms such as
progressive decrease in exerciseprogressive decrease in exercise
tolerance or functional class or evidencetolerance or functional class or evidence
of right heart failureof right heart failure
 Progressive RV enlargement oftenProgressive RV enlargement often
accompanied by increasing TR owing toaccompanied by increasing TR owing to
annular dilationannular dilation
 Development or progression of atrialDevelopment or progression of atrial

52.  Homograft valves, xenograft valves,Homograft valves, xenograft valves,
pericardial valves, and mechanical valvespericardial valves, and mechanical valves
 Percutaneous pulmonary valvePercutaneous pulmonary valve
replacement with a bovine jugular venousreplacement with a bovine jugular venous
valve sutured inside a stent was firstvalve sutured inside a stent was first
described in a human in 2000described in a human in 2000

53.  Symptoms are unreliable in reflectingSymptoms are unreliable in reflecting
hemodynamic severity because theyhemodynamic severity because they
usually are seen only in patients withusually are seen only in patients with
severe or critical obstructionsevere or critical obstruction
 The course of mild stenosis is benignThe course of mild stenosis is benign
 No intervention is requiredNo intervention is required
 The hemodynamic response to exercise inThe hemodynamic response to exercise in
these patients is normalthese patients is normal

54.  Patients with moderate stenosis may developPatients with moderate stenosis may develop
progressively greater outflow tract obstruction,progressively greater outflow tract obstruction,
especially during periods of rapid growthespecially during periods of rapid growth
 In most asymptomatic patients with moderateIn most asymptomatic patients with moderate
pulmonary valve stenosis formal exercise testingpulmonary valve stenosis formal exercise testing
demonstrated subnormal cardiac outputdemonstrated subnormal cardiac output
response and abnormal increase in rightresponse and abnormal increase in right
ventricular end-diastolic pressure suggestingventricular end-diastolic pressure suggesting
that both systolic and diastolic dysfunction maythat both systolic and diastolic dysfunction may
be caused by long-standing moderatebe caused by long-standing moderate

55.  Children with severe stenosis commonlyChildren with severe stenosis commonly
develop increasingly severe obstructiondevelop increasingly severe obstruction
 Result from disproportionate growth of theResult from disproportionate growth of the
child relative to the pulmonary valvechild relative to the pulmonary valve
 Exercise hemodynamics in children andExercise hemodynamics in children and
adults with severe obstruction before andadults with severe obstruction before and
after valvotomy suggest that irreversibleafter valvotomy suggest that irreversible
changes in cardiac function can develop ifchanges in cardiac function can develop if
treatment is delayed beyond childhoodtreatment is delayed beyond childhood

56.  Patients with severe stenosis have a lowerPatients with severe stenosis have a lower
cardiac stroke index at rest and during exercisecardiac stroke index at rest and during exercise
and also higher RVEDP at rest and abnormaland also higher RVEDP at rest and abnormal
increase with exercise than patients with milderincrease with exercise than patients with milder
diseasedisease
 Following valvotomy there is an improvement inFollowing valvotomy there is an improvement in
stroke index and reduction in RVEDP at rest andstroke index and reduction in RVEDP at rest and
during exercise within 1 year of operationduring exercise within 1 year of operation
 In contrast this improvement is not observed inIn contrast this improvement is not observed in
older patientsolder patients
 Implying permanent changes e.g., myocardial fibrosisImplying permanent changes e.g., myocardial fibrosis
have occurredhave occurred

58.  5% of all cases of right ventricular outflow5% of all cases of right ventricular outflow
tract obstructiontract obstruction
 Two types:Two types:
 Obstructive fibrous band at the junction of theObstructive fibrous band at the junction of the
main right ventricular cavity and the proximalmain right ventricular cavity and the proximal
infundibulum that closely resembles double-infundibulum that closely resembles double-
chambered right ventriclechambered right ventricle
 Narrowing of the infundibulum is due toNarrowing of the infundibulum is due to
fibromuscular thickening of its wall, which mayfibromuscular thickening of its wall, which may
extend from immediately below the pulmonaryextend from immediately below the pulmonary
valve to the proximal infundibulumvalve to the proximal infundibulum

59.  ““Double-chambered right ventricle“Double-chambered right ventricle“
 Aberrant hypertrophied muscular bands - divideAberrant hypertrophied muscular bands - divide
the RV cavity into a proximal high-pressurethe RV cavity into a proximal high-pressure
chamber and a distal low-pressure chamber tochamber and a distal low-pressure chamber to
the hypertrophied muscle bandsthe hypertrophied muscle bands
 Orientation differs from that of the moderatorOrientation differs from that of the moderator
bandband
 Septal attachment of the moderator band is usually inSeptal attachment of the moderator band is usually in
the apical third of the ventricular septumthe apical third of the ventricular septum
 Septal attachment of anomalous muscle bundles areSeptal attachment of anomalous muscle bundles are

60.  Visualized best from – subcostal andVisualized best from – subcostal and
parasternal viewsparasternal views
 Presence or absence of a ventricularPresence or absence of a ventricular
septal defect can be documentedseptal defect can be documented
 Abnormal fluttering of the pulmonary valveAbnormal fluttering of the pulmonary valve
is often a concomitant findingis often a concomitant finding
 Treatment is surgical correctionTreatment is surgical correction