VSD

• Communication b/t two ventricles

VSD

• May occur alone or with other abnormalities

• About one-third of small VSDs close spontaneously

Ventricular Septal Defect

• Commonest acyanotic CHD (~25%)

• Associated with-Down Syndrome

Fetal hydantoin syndrome

Fetal alcohol syndrome

Trisomy 13, 18

Apert syndrome

Anatomy

• Compartments of ventricular septum:

- Membranous septum

- Inlet septum

- Trabecular septum

- Outlet or infundibular septum

• Defects result from a deficiency of growth or failure of alignment or fusion of component parts

Classification-pathology

1.Membranous VSD- (perimembranous, paramembranous , conoventricular, infracristal, subaortic) – Most common (90%)

2.Muscular VSD- (Swiss cheese ,inlet, trabecular, central, apical, marginal ,or outlet types)

3. Supracristal VSD- (subpulmonary, outlet, infundibular, or conoseptal. subarterial defect) Least common

Classification-pathology

Hemodynamics:

• L→R shunt in ventricles occur with high pressure gradient throughout systole – pansystolic murmur

• Blood to normal pulmonary valve – ejection systolic murmur

• Large vol of blood to lungs – pul plethora• Blood to left atrium – Lt. atrial enlrgement• Blood to normal mitral valve – delayed

diastolic murmur at apex

Hemodynamics

• Lt ventricles to outlets – empties relatively early – early A2

• Rt ventricle & pul artery – increased ejection time – delayed P2-S2 widely split &variable

Hemodynamics

Hemodynamics

• Depends on: a) size of the shunt

b) PVR

• Based on size of VSD:

- Restrictive VSD(<0.5 cm2 )

- Moderately restrictive VSD

- Non-restrictive (>1 cm2 )

Restrictive VSD

• Small, hemodynamically insignificant • Size <0.5 cm2

• Between 80% and 85% of all VSDs• All close spontanously 50% by 2 years 90% by 6 years 10% during school years• Muscular close sooner than membranous

A moderately restrictive VSD

• Size -> 0.5 cm2 (>5mm) in diameter

• Moderate shunt (Qp:Qs = 1.5-2.5:1.0)

• May lead to left atrial and LV dilation and dysfunction, as well as a variable increase in pulmonary vascular resistance

Large nonrestrictive VSDs

• Large VSDs with normal PVR

• Usually >1.0 (>10 mm) in diameter

• Usually requires surgery

• Will develop CHF and FTT by age 3-6 months

Clinical Manifestations:

1. Small VSD: asymptomatic, normal growth

2. Moderate to large: repeated chest infections, Effort intolerance ,fatigue , failure to thrive, pulmonary HTN

3. If unoperated: Pulmonary HTN, cyanosis and decreased level of activity

Physical examination

1. Small VSD: well developed, acyanotic

2. Moderate VSD: forceful LV impulse , prominent systolic thrill along the lower left sternal border

Physical examination

Large VSD: tachypneic, repeated chest infections, poor weight gain, CHF dyspnea, feeding difficulties, poor growth, profuse perspiration, recurrent pulmonary infections, and cardiac failure in early infancy.

Reversal of shunt: cyanosis, clubbing, respiratory distress.

Auscultation

• Heart sounds

• S1 : masked by pansystolic murmur

• S2: masked but can be heard at 2nd lt ICS – widely split and variable, with accentuated P2 - single and loud (PAH)

• S3: maybe audible at the apex

Murmurs

• Shunt - loud, harsh, or blowing pansystolic murmur grade 3-5/6 best heard at left 3rd & 4th interspaces is widely transmitted over the precordium at lower LSB

• Flow – • Pulmonary : ejection murmur (drowned)• Mitral : rumbling delayed diastolic murmur

at the cardiac apex, indicates a Qp:Qs of 2:1 or greater

Fairly large perimembranous VSD in

Chest radiography

• Small VSDs -N

• Medium- VSDs -minimal cardiomegaly and a borderline increase in pulmonary vasculature

• Large VSDs – gross cardiomegaly . The pulmonary vascular markings are increased and frank pulmonary edema (Plethoric) if pul arterial HTN

• Oligemic lung fields in reversal of shunt, pul stenosis

Electrocardiography

• Depends on shunt size & degree of pulmonary hypertension

• Small VSDs - N tracing

• Medium VSDs – broad, notched P wave ( left atrial overload), LVH

• Large VSDs – RVH with right-axis deviation. With further progression - biventricular hypertrophy; P waves may be notched or peaked

• RVH in Eisenmenger’s complex

Echocardiography

• Echo - Number, position & size of defect, chamber size

• Two-dimensional echo – site, size of defect ,pul. stenosis or pul HTN

Management:• Large VSDs Medical:

Treatment of chest infection Control of heart failure Infective endocarditis prophylaxis Dental hygiene Frequent feeding of high calorie formula, correction of

anemia Non-surgical closure with umbrella device

Surgical

• Repair of defect under open heart surgery

• Clamshell-type catheter occlusion -closing apical muscular VSDs.

• Transcatheter device closure - trabecular (muscular) and perimembranous VSDs

Indications of surgery:• Large defects- if CHF not responding to

medical management (within first 6 months of life)

• After 1 year of age, significant LR shunt, Qp: Qs ratio at least 2:1 without pul HTN

• Supracristal VSD of any size because of the high risk of aortic valve regurgitation

Contraindication of surgery

1. Severe pulmonary vascular disease

2.Muscular septum VSDs , particularly apical defects and multiple (Swiss cheese–type)

Natural history• Small VSD – Spontaneous closure( 30-

50%) during 1st yr of life (membranous & muscular defects)

• Small muscular VSDs are more likely to close 80% than membranous VSDs 35%

• The vast majority 45% close by age 4 years

• Spontaneous closure has been reported in adults

Mod to Large VSDs

• Less commonly close spontaneously

• CHF develops in large VSDs after 8 weeks of age

• Repeated chest infection ,FTT

• IE –independent of VSD size – rare in < 2yrs .risk is 2% above 2 yrs

Natural History:

• Pulmonary hypertension →pulmonary vascular disease (Eisenmenger syndrome

• Aortic valve regurgitation - the greatest risk supracristal VSD