Ventricular Septal Defects (VSD)

Last updated 2015 - Written by Dr. Benjamin Marsh

Definition

A ventricular septal defect is an opening of the ventricular septum, they can occur in a variety of locations and can be multiple in number. If the defect is greater than 50% the diameter of the aorta it is considered large.  It is the most common congenital lesion (2.5/1000 live births).
Associations include: with Holt-Oram syndrome, familial ASD with progressive AV block, trisomy 13, 18 and 21, Rubenstein-Taybi syndrome, VACTERL association, among others.

Presentation

Typically asymptomatic, often not heard in nursery but apparent in first postnatal checkup or found incidentally after other congenital anomalies are worked up. Large VSDs can result in tachypnea (often exacerbated by superimposed RSV infection), failure to thrive, (Requiring 20+ to take a bottle), pulmonary infections, CHF and exercise intolerance.

CHF develops in infants with large VSD around 6-8wks as pulmonary vascular resistance drops with normal transitioning.
Older kids can present with arrhythmias, CHF, hemoptysis, and bacterial endocarditis.

2-5/6 SEM-pansystolic at LLSB, if large pt may have apical diastolic rumble (volume overload of LA). Resultant pulmonary hypertension can intensify and narrowly split P2.  Can have systolic thrill at LLSB

EKG may be normal in small VSDs. Findings include LVH and LAH. If large there can be BVH and LAH. If there is resultant pulmonary veno-occlusive disease there may be pure RVH.

Diagnosis is made by 2D echo, watch for increased right ventricular pressures.

Management

Spontaneous closure in 30-40%, especially in the first year of life and in small trabecular VSDs. Inlet and infundibular VSDs do not become smaller or spontaneously close. Small persistent VSDs at 1yo can be managed conservatively with re-evaluation every 3y.

Medical

Digitalis and diuretics are the mainstay of treatment. Watch for and correct anemia.
No exercise restrictions unless there is pulmonary hypertension. Give prophylactic antibiotics for dental procedures.

Surgical

Catheter delivered devices are preferred especially if over 1yo and muscular in location. Surgical closure is done under cardiopulmonary bypass and hypothermia. Transatrial approach used in membranous, inlet and muscular defects proximal to the moderator band. Transpulmonary valve approach used in subpulmonary defects. Right ventriculotomy is used for closure of apical defects (this approach has a high morbidity)

Indications: If L->R shunt is 2:1, infants with medically refractory CHF and failure to thrive. Large VSD with increased PVR prompts earlier intervention.  
Medically responsive infants can wait till 12-18mo for surgery.
If asymptomatic surgery can be delayed to 2-4yo.
Contraindications: PVR/SVR is >0.5 or there is R->L shunting.

Complicated defects

If a large PDA is also present this can be closed at 6-8wks, with later VSD closure. If the VSD is large then earlier concomitant closure may be warranted.
If a Co-arctation is present treatment strategies are controversial.
If aortic regurgitation is seen (more common in infundibular or perimembraneous VS), prompt surgical closure is indicated.
Pulmonary Artery banding only done as temporizing measure if additional lesions make a full repair difficult.

Prognosis

Smaller medically managed VSDs carry a small risk of bacterial endocarditis in adulthood.

Pts with large VSDs that were surgically managed commonly regain their destined position on the growth chart, though late closure can result in smaller stature than siblings. 40-90% will have a RBBB depending on operative approach, especially operation occurred at < 6mo.

Postsurgical follow up every 1-2 years. Complete right bundle branch block occurs in almost all surgically managed infants younger than 6 months of age.

Sources: Park Ch 3, Nadas’ Ch 30, Nelsons Ch 420