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Detailed information of VENTRICULAR SEPTAL DEFECT -VSD
VENTRICULAR SEPTAL DEFECT
DEFINITION:
An acyanotic congenital heart disease characterized by defects in
the ventricular septum.
EPIDEMIOLOGY:
- incidence: 25-30% of all congenital cardiac lesions
- age of first detection:
- newborn - 2 days (small VSD) to >1 week (large VSD)
- risk factors:
- certain chromosomal and genetic disorders and syndromes
TYPES (4):
- defect occurs between the crista supraventricularis and
pulmonary valve
- may be associated with pulmonary stenosis
2. Type 2 (Perimembranous) - 60-80%
- defect occurs within the membranous septum
3. Type 3
- defect occurs superior to the crista supraventricularis
- defect occurs in the inlet portion of the right ventricle
beneath the septal leaflet of the tricuspid valve
- may impinge on an aortic sinus causing aortic insufficiency
4. Type 4 (Muscular)
- defect occurs in the muscular septum
- may be single or multiple (Swiss-cheese type)
ASSOCIATED ANOMALIES:
- ASD
- Pulmonary Stenosis
- Tricuspid Atresia
- TGA
- Patent Ductus Arteriosus
- Coarctation of the Aorta
PATHOPHYSIOLOGY:
- less than ½ the surface area of the aortic root
- pulmonary to systemic flow ratio <1.75:1
- insignificant L->R shunt
- normal cardiac chambers and pulmonary vascular bed
2. Large Defects (Unrestrictive)
- greater than the surface area of the aortic root
- pulmonary to systemic flow ratio >3:1
- usually appears several weeks after birth due to the natural
fall in pulmonary vascular resistence as the muscular media of
the small pulmonary arteries and arterioles involutes
- degree of L->R shunt is determined by:
- size of defect
- ratio of pulmonary to systemic vascular resistence
- significant L->R shunt produces:
- RV and pulmonary artery hypertension
- enlarged pulmonary artery trunk and left atrium
- left ventricular (LV) volume overload and LV enlargement
CLINICAL FEATURES:
- small defects with trivial L->R shunt
- usually found on routine physical examination
2. Symptomatic
- large defects with significant pulmonary hypertension
- CHF
- dyspnea
- failure to thrive
- feeding difficulties
- profuse perspiration
- recurrent lung infections
2. Signs
2. Palpation
- thrill @ LLSB (VSD murmer)
- parasternal lift (RVH) and apical thrust (LVH)
3. Auscultation
- initially widely split due to prolonged RV ejection
time due to increased RV blood volume
- later single as pulmonary pressure approaches systemic
pressure
2. Murmurs
- loud (grade 3/6), harsh, blowing (high-pitched)
pansystolic murmur @ L 3rd and 4th interspaces
2. Diastolic
- short mid-diastolic murmur @ apex
- increased blood flow across the mitral valve
2. Aortic Insufficiency
- in 5% of VSD's
- diastolic murmur @ mLSB
3. Complications
- subacute bacterial endocarditis (SBE)
- recurrent respiratory infections
2. Structural Defects
- produces a two-chambered RV with mid cavity obstruction
- protects pulmonary circulation from long term pulmonary
hypertension
- may eventually produce a R->L shunt and cyanosis
- presents after 1 year of age
2. Aortic Valve Insufficiency
- aortic valve prolapse
- formation of a subaortic shelf (stenosis) with the
perimembranous type of defect
- presents after 1 year of age
3. Pulmonary Hypertension (PH)
4. Congestive Heart Failure (CHF)
- shortness of breath, exercise intolerance
INVESTIGATIONS:
- cardiomegaly with prominence of ventricles, LA, and PA
- increased pulmonary vasculature
2. ECG
- LVH -> biventricular hypertrophy -> RVH
- LAH
3. 2D-Echo
- VSD
- volume overload of ventricles and LA
- to follow for the development of a 2-chambered RV, subaortic
stenosis, aortic valve prolapse
MANAGEMENT:
- VSD's are well tolerated during childhood and there is no
need for restriction of activity
- adenoidectomy
- dental surgery
- oropharyngeal surgical procedures
- tonsillectomy
- any instrumentation of the genitourinary and lower
intestinal tracts
2. Congestive Heart Failure
2. Surgery
- unsuccessful medical control of complications
- failure to thrive
- recurrent lung infections
- congestive heart failure, exercise intolerance
- one episode of subacute bacterial endocarditis
- new onset of mid diastolic murmur (aortic
insufficiency)
- pulmonary hypertension (new onset of loud narrow S2,
RV heave, loss of thrill; ECG with RVH)
2. Echocardiogram
- pulmonary to systemic flow ratio >3:1
- SVR/PVR = 3:1 (a ratio of <3:1 suggests significant
pulmonary hypertension and high surgical risk)
3. After 1 year of Age
- mortality rate for direct repair is 42% if <1 year
- usually do not refer to a cardiologist until 1 year
- may band the pulmonary artery prior to 1 year of age
then complete repair of the VSD at 3-4 years of age
2. Types
- indicated if repair needed prior to 1 year of age
2. Direct Repair
2. Dacron Patch
3. Post-Operative Complications
- from chest wall or ventriculotomy
- persistent drainage from chest tubes, cardiac tamponade,
or hemothorax are indications for reoperation
2. Pulmonary Edema
- after banding or direct repair if additional lesions
present
3. Heart Block
- due to injury to the conduction bundle
4. Heart Failure
- with elevated CVP, low cardiac output, and hypotension
- particularly in patients with pulmonary hypertension
- may treat with isoproterenol or tolazoline to lower
pulmonary resistance
5. Death
- mortality rate for direct repair is about 7%
- only in those with severe pulmonary hypertension
3. Prognosis
- 75-80% close spontaneously
- 90% of muscular VSD's
- 70% of perimembranous VSD's
- 20-25% remain open
- clinically insignificant
- need prophylactic antibiotics for procedures
2. Large (Unrestrictive) VSD
- all remain open and will eventually need to be surgically
corrected after a period of medical management
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Pediatric Database - VENTRICULAR SEPTAL DEFECT -VSD
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