AUTHOR AND EDITOR INFORMATION

Section 1 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

INTRODUCTION

Section 2 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Ventricular septal defect (VSD) is an abnormal opening in the interventricular septum that allows communication between the right and left ventricular (LV) cavities. VSDs are the most common congenital intracardiac defects of clinical importance. VSDs may vary in size, number, and location within the interventricular septum, and the clinical implications often depend upon these factors. VSDs may occur as isolated lesions or in conjunction with other cardiac anomalies.

History of the Procedure

In 1879, Roger first characterized the clinical presentation of VSD.¹ VSD had been recognized prior to this date but was less well understood.² In 1897, Eisenmenger reported autopsy findings of a 32-year-old patient with a large VSD and cyanosis. He described the syndrome now referred to  as progressive elevation of pulmonary vascular resistance with reversal of intracardiac shunting and cyanosis.

In 1951, at UCLA, Muller performed what current surgeons describe as a pulmonary artery band on a 5-month-old child with a presumed diagnosis of a large VSD.³ He reduced the size of the main pulmonary artery by removing part of the wall of the main pulmonary artery (MPA), and then placed a polyethylene strip around the stenotic area. Blalock performed two similar operations before 1951, but both of those patients died at surgery.³ In 1952, Muller and Damman reported the short-term success of this operation. In 1955, Lillehei and colleagues performed the first successful VSD closure under direct vision using cross-circulation from another human at the University of Minnesota. In 1956, Kirklin performed the first successful closure of VSD using cardiopulmonary bypass at the Mayo Clinic.

As cardiopulmonary bypass became more widely reproducible in younger children and infants, palliative surgery (to reduce pulmonary hypertension and reduce excessive pulmonary blood flow) was replaced with definitive reparative closure (to eliminate intracardiac shunting).

Problem

A hemodynamically significant VSD causes excess pulmonary blood flow.  The size of the VSD and the level of pulmonary vascular resistance (PVR) determine the degree of pulmonary overcirculation.  Flow from the left ventricle (systemic circulation) to the right ventricle (pulmonary circulation) creates a left-to-right shunt at the ventricular level (see Pathophysiology). Additionally, a large VSD causes pulmonary hypertension.  Early consequences of pulmonary overcirculation create a picture of congestive heart failure (CHF). If the VSD is sufficiently large to cause pulmonary hypertension, irreversible elevation of PVR results in some patients. 

In the initial stages of elevated PVR, pulmonary blood flow reduces and symptoms of pulmonary overcirculation often diminish. Elevated PVR tends to be progressive, and eventually exceeds the systemic vascular resistance. By the time PVR exceeds systemic vascular resistance, architectural changes have remodeled the pulmonary vasculature. Even with surgical repair of the VSD, the changes in pulmonary vasculature are irreversible. Right-to-left shunting at the VSD and diminished pulmonary blood flow dominate the physiologic picture, and progressive cyanosis ensues. VSD also causes aortic valve insufficiency, left-sided heart failure, and endocarditis in some patients. 

Frequency

Isolated VSD occurs in approximately 2 per 1000 live births and accounts for more than 20% of all forms of congenital heart disease.

Etiology

VSDs occur early in fetal development during the complex process of ventricular partitioning. VSDs result from an error in development or alignment of the muscular septum (with inlet, trabecular or apical, and outlet components), membranous septum, and aortopulmonary septum. Which septal component(s) forms abnormally determines the anatomic location of the VSD within the interventricular septum (see Relevant Anatomy). Chromosomal, familial, environmental, and geographic factors may hasten the development of VSD. For example, Asian children have a higher incidence of conal, or subarterial, defects. Children of parents with VSD are more likely to have congenital heart disease (although not necessarily VSD). Maternal infections such as rubella may contribute to VSD development.

Pathophysiology

Isolated VSD allows intracardiac shunting. Typically, a left-to-right shunt dominates because pulmonary vascular resistance (PVR) is lower than systemic vascular resistance. The magnitude of shunting depends upon the size of the VSD and the degree of difference between pulmonary and systemic vascular resistances. The Qp:Qs ratio describes the degree and direction of shunting.

Normally, PVR drops in the first few hours of life, leaving PVR significantly lower than the systemic vascular resistance. If a VSD is present, blood preferentially flows from the left ventricle to the right ventricle as well as to the body through the aorta. This left-to-right shunt allows oxygenated blood from the left ventricle to cross the VSD into the right ventricle and recirculate through the pulmonary circulation (ie, pulmonary overcirculation). The resultant Qp:Qs is greater than 1.

A large VSD delays the drop in PVR after birth. The pulmonary vascular resistance still typically drops, but over the course of days to weeks rather than hours to days. As the pulmonary vascular resistance drops, the magnitude of shunting and the magnitude of pulmonary blood flow increases. This results in a Qp:Qs ratio that may exceed 3:1. The excess pulmonary blood flow results in excess flow through the left atrium and left ventricle. Markedly elevated pulmonary blood flow enlarges the left atrium and left ventricle. If the VSD is large, the pressure equalizes between the right and left ventricles. Typically, in a normal heart, right-sided ventricular pressure is a fraction of left-sided ventricular pressure.

A large left-to-right shunt sets off many complex physiologic reactions. Compensatory mechanisms (including increased circulating catecholamines and increased sympathetic nervous tone) maintain systemic output and organ perfusion. Activation of the renin-angiotensin axis produces retention of sodium and water. The resultant increased total blood volume exacerbates ventricular overload and pulmonary congestion. The magnitude of these changes is directly related to the magnitude of left-to-right shunting.

If PVR is higher than systemic vascular resistance (as in Eisenmenger syndrome), a net right-to-left intracardiac shunt results, with deoxygenated blood from the systemic venous return crossing the VSD into the left ventricle and re-entering the systemic circulation. Qp:Qs is less than 1, resulting in systemic arterial desaturation or cyanosis. The development of pulmonary vascular occlusive disease is unpredictable, but typically is restricted to patients who have no restriction to pressure at the VSD.

PVR progressively rises due to irreversible histologic changes in pulmonary arteriolar walls. When pulmonary vascular resistance exceeds systemic vascular resistance, shunt direction reverses, resulting in cyanosis (Eisenmenger syndrome). Generally, pulmonary vascular occlusive disease represents a chronic consequence of nonrestrictive VSD and is not seen before age 6 months.  In many patients who develop irreversible pulmonary vascular disease, the onset is seen after age 1 year. The most severe manifestations of Eisenmenger syndrome do not generally occur until the second decade of life, at the earliest.

Clinical

The clinical presentation of children with isolated VSD depends on the magnitude of left-to-right shunting and the presence of pulmonary hypertension. Children with small, flow-restrictive VSDs (ie, right-sided ventricular pressure is significantly less than left-sided ventricular pressure) are asymptomatic. Such children may come to the attention of a cardiologist because a murmur is detected during general examination. These children usually remain asymptomatic with minimal or no medical therapy. Small VSDs frequently close spontaneously. The probability of spontaneous closure is highest during the first year of life. Perimembranous VSDs and trabecular muscular VSDs close spontaneously. Inlet muscular VSDs and supracristal VSDs require surgery for closure.

Children with larger VSDs and greater left-to-right shunting present with the signs and symptoms of CHF. Because the normal decline in PVR is delayed in the presence of a large VSD, infants often do not develop signs of pulmonary overcirculation for a few weeks after birth.  As PVR drops, left-to-right shunting increases, and pulmonary blood flow increases. Symptoms include tachypnea, poor feeding, and failure to thrive. If pulmonary blood flow magnitude is high, interstitial lung edema develops. Dyspnea and increased work of breathing herald the development of pulmonary edema.  

Patients are occasionally seen with a pressure-restrictive, moderately sized VSD and pulmonary overcirculation. They fall in between the small, pressure-restrictive VSDs and the nonrestrictive, large VSDs. These infants do not have a significant risk of pulmonary vascular disease, but benefit from surgery.

On physical examination, quiet tachypnea is observed, and the resting heart rate may be increased. The precordial impulse is increased in intensity. Palpable cardiomegaly with lateral displacement of the apical impulse may be present, as well as a precordial thrill. The first heart sound is normal. The second heart sound may be prominent or may be difficult to separate from the holosystolic murmur. If heard, the second heart sound is usually single or narrowly split.  In pulmonary hypertension, P2 is accentuated. A harsh, holosystolic murmur is heard over the entire precordium in large and moderately sized VSD. 

If the Qp:Qs ratio is greater than 2, a diastolic filling sound is often heard at the apex. If the VSD is small, the murmur has a higher pitch and may be localized. The frequency of the holosystolic murmur predicts the pressure difference between the ventricles. Higher-pitched murmurs predict a large pressure difference. Lower-pitched murmurs predict elevated right ventricular pressure. Hepatomegaly is present when the VSD is large and pulmonary overcirculation is noted. Rales or crackles are unusual in the first few months or life, even if the VSD is large. 

Patients with VSD and high PVR may remain relatively asymptomatic until the final stages of the disease. If PVR has progressed, the left-to-right shunt is either (1) diminished, possibly with no audible murmur, or (2) nonexistent after having once been audible. This finding indicates equalization of pressures or early reversal of the shunt flow, which is a poor prognostic indicator. As pulmonary vascular disease progresses further, cyanosis and right-sided heart failure herald shunt reversal to right-to-left flow.

INDICATIONS

Section 3 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

The following are indications for surgery:

• Infants with unrestrictive VSDs who (1) have congestive heart failure (CHF) that is refractory to medical management and who (2) are not growing should undergo surgical closure, regardless of age or size. Even if the VSD is large, for babies to stop growing in the first 3 months of life is unusual.
• Infants with unrestrictive, large VSDs who are growing should be observed for signs that the VSD is becoming pressure restrictive and decreasing. If the VSD remains large and unrestrictive, most infants should undergo surgical closure at age 4-6 months.  However, this is somewhat controversial, and although a repair later in the first year of life is acceptable, a progressive risk of pulmonary vascular disease after age 6 months exists. 
• Infants with a moderate-sized, pressure-restrictive VSD should undergo repair if their growth is abnormal or if evidence is seen of progressive or persistent left-sided heart enlargement after age 6 months. After infancy, a child with a moderately sized VSD who develops left-sided heart dilation should undergo surgical closure.
• Most children who undergo surgical VSD closure no longer require cardiac catheterization. Beyond infancy, if a child has a large VSD with no pressure restriction, cardiac catheterization may be helpful. The most important piece of information obtained at catheterization is the degree of elevation in pulmonary vascular resistance (PVR). Typically, children without VSD have a PVR of 2 Wood units (2 resistance units or 2 units), indexed for body surface area. The body size adjustment is in the numerator, not the denominator. If the PVR is greater than 2 units but less than 4 units, pulmonary vascular disease is not present.
• • Patients with a large VSD and a PVR greater than 4 units but less than 8 units have some degree of PVR. If the PVR drops with administration of supplemental oxygen, surgery should be performed. Most of those children do not have elevated pulmonary artery pressure at rest after surgery. They do have an increased risk of elevated pulmonary artery pressure during exercise, suggesting an abnormal pulmonary vascular bed.
  • If catheterization reveals a PVR greater than 8 units, vasodilator testing is indicated. If the PVR drops to less than 8 units in response to oxygen or inhaled nitric oxide, surgery should be performed. Most of these patients also have normal or mildly elevated pulmonary artery pressure at birth, and most are healthy after surgery. Some children from this group develop progressive pulmonary vascular obstructive disease. These children should be closely monitored for postsurgery pulmonary hypertension. If pulmonary hypertension persists or develops, appropriate pulmonary vasodilator therapy lessens symptoms and prolongs life.
  • If the PVR remains above 8 units, even with vasodilator testing, pulmonary vascular disease is severe and progressive in most cases.  Surgery does not prolong life or improve health in this group, thus is not indicated. 
• Other indications for surgical closure include the following:
• • Progressive aortic insufficiency. This occurs in a small minority of patients with perimembranous VSD and more than half of patients with supracristal VSD.  Development of aortic insufficiency with prolapse of an aortic valve leaflet also warrants surgery. Prolapse of an aortic valve leaflet into a perimembranous VSD without aortic insufficiency is a controversial indication. Some cardiologists advocate for surgery and others advocate for no intervention. No definitive data exist to guide the approach to aortic valve prolapse without insufficiency. In patients with supracristal VSD, the likelihood of progressive aortic valve insufficiency is higher, and aortic prolapse warrants surgical repair.
  • Endocarditis
  • Progressive left ventricular enlargement or decreased left ventricular function
• Pulmonary artery banding is reserved for patients with unique circumstances.  A small infant with multiple trabecular muscular VSDs may have a better result from definitive surgery after he or she has grown. In addition, some VSDs may disappear with time and growth. Certain surgeons have advocated pulmonary artery banding for low birth-weight infants. Others have recommended the same approach as that used for term newborns.

RELEVANT ANATOMY

Section 4 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

The ventricular septum may be divided into 4 components. The inlet septum is smooth walled and lies beneath the tricuspid valve, extending from the septal attachment of the tricuspid valve to the distal attachment of the tricuspid tensor apparatus. The apical trabecular septum is covered with trabecular muscle and lies distally in the septum. The infundibular, or outlet, septum is separated from the trabecular portion. It lies anterior and superior to the septal band and makes up the portion of the outflow tracts. The membranous septum is fibrous only and lies adjacent to the anteroseptal tricuspid commissure on the right side and the right posterior aortic commissure and anterior mitral leaflet on the left side.

Lev and colleagues delineated the anatomy of the conduction system associated with septal defects, which decreased the incidence of iatrogenic atrioventricular (AV) block associated with surgical ventricular septal defect (VSD) closure.⁴

In 1956, Becu used numbers to describe the location, but that nomenclature has since fallen into disuse.⁵ VSDs are generally classified into 1 of 4 groups depending upon their location in the interventricular septum. The 4 groups are as follows: 

• Supracristal VSD (Becu type 1):  Supracristal VSDs comprise approximately 10% of VSDs in most populations, but are the most common VSD in some Asian populations.  Alternate nomenclature systems refer to this VSD as conal, outlet, subarterial, or infundibular. They lie just beneath the pulmonary and aortic valve annuli. Because of the anatomic location and Venturi effect from VSD flow, prolapse of the right coronary cusp of the aortic valve into the defect may result in significant aortic insufficiency. If significant extension into other portions of the septum is absent, the conduction system is distant to this type of defect.
• Perimembranous VSD (Becu type II): Perimembranous VSDs make up most VSDs that require surgery. In some series, perimembranous VSDs make up 80% of the surgical VSD volume. Perimembranous VSDs lie in the region of the membranous septum (posterior and inferior to type I VSD). Alternate nomenclature systems have termed these VSDs paramembranous, membranous, conoventricular, or infracristal. In the right ventricle, perimembranous defects lie between the inlet and outlet portions of the septum. In the left ventricle, perimembranous defects lie in the outlet portion beneath the aortic valve commissure between the noncoronary and right coronary cusps. Aortic valve cusp prolapse with or without aortic valve insufficiency is possible. The conduction tissue passes along the posteroinferior margin of the VSD.
• Inlet muscular VSD (Becu type III): Approximately 5% of VSDs are inlet muscular VSDs. These lie posteriorly in the inlet septum, immediately beneath the septal leaflet of the tricuspid valve. Many surgeons separate this type of VSD and consider it a type of AV septal defect or AV canal defect. The AV node and conduction bundles pass along the leftward aspect of the inferior margin of the defect.
• Trabecular muscular VSD (Becu type IV): Approximately 5% of VSDs that require surgery are trabecular muscular VSDs. These VSDs lie within the trabecular septum and may be isolated or multiple. Because pectinate muscles cover them, muscular VSDs often have multiple openings on different planes on the right ventricular side, complicating visual definition and repair of the entirety of the defect(s). In early infancy, trabecular muscular VSDs are as common as perimembranous VSDs. Most of these defects undergo spontaneous closure.

CONTRAINDICATIONS

Section 5 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Fixed pulmonary vascular obstructive disease (see Indications), resulting in diminution of left-to-right shunting or even right-to-left shunting, is an absolute contraindication to VSD closure. In this situation, the VSD acts as a "pop-off valve," allowing right-to-left flow to bypass the lungs and maintain systemic cardiac output. In this situation, closure of this defect results in right-sided ventricular (RV) failure and low cardiac output.

WORKUP

Section 6 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Lab Studies

• Electrolyte panel: Assess electrolyte balance, level of hydration, and renal function, particularly for children receiving diuretics.
• CBC count with differential: Assess for the presence of polycythemia or infection.

Imaging Studies

• Chest radiography: Findings in a patient with ventricular septal defect (VSD) are nonspecific. With small VSDs, radiograph findings are usually normal. With larger defects, the cardiac silhouette is enlarged with a prominent left ventricular (LV) contour. The left atrium is usually enlarged with possible splaying of the mainstem bronchi. Pulmonary vascular markings are increased, indicating an increased pulmonary blood flow. If pulmonary overcirculation is severe, interstitial edema appears. If elevated pulmonary vascular resistance is present, pulmonary vascular markings may be unremarkable or even absent.
• Echocardiography: The mainstay of diagnosis and evaluation in the current era is 2-dimensional and Doppler echocardiography. Parasternal short-axis views permit imaging of the entire ventricular septum and may clearly delineate all forms of VSD. The 4-chamber view provides the best images of inlet and muscular defects. Ultrasound assessment has become an integral part of the noninvasive evaluation of a patient with VSD.
• MRI: Gated MRI provides excellent anatomic definition of the VSD as well as other cardiac defects. Cine MRI provides functional assessment of the wall topology as well as shunt flow dynamics.

Other Tests

• Electrocardiography: Electrocardiographic (ECG) findings may be normal or may reflect LV hypertrophy. Right ventricular hypertrophy may also be noted with larger VSDs. Right ventricular hypertrophy also results from increased pulmonary vascular resistance. Inlet muscular VSDs typically exhibit left axis deviation of the frontal plane QRS axis. Occasionally, perimembranous VSD also demonstrates left axis deviation.

Diagnostic Procedures

• Cardiac catheterization: When coupled with cineangiocardiography, catheterization provides accurate anatomic and physiologic definition of VSD. The procedure may be used to assess pulmonary vascular resistance and reactivity, as well as shunt fraction (Qp:Qs). In the current era, catheterization is not performed routinely, but rather reserved for children requiring assessment of pulmonary vascular resistance or for those who may undergo catheter-based closure techniques.

TREATMENT

Section 7 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Medical therapy

Medical therapy is used to temporize the hemodynamic consequences of a large left-to-right shunt and pulmonary overcirculation. No medicine diminishes Qp:Qs ratio or effectively decreases pulmonary blood flow. Significant studies of the effects of medication on large ventricular septal defects (VSDs) are sparse and difficult to interpret in support of medical therapy. The goal of medical therapy is to control pulmonary edema, decrease the work of breathing, and allow for growth.

Infants with large defects may present with severe congestive heart failure (CHF). Infants with severe respiratory distress should be hospitalized. Almost all practitioners use diuretics in this situation, but experimental evidence to support its use is sparse. Infants with quiet tachypnea may be cared for as outpatients. Afterload reduction with angiotensin-converting enzyme (ACE) inhibitors does not affect Qp:Qs but may improve systemic blood flow and systemic oxygen delivery. For infants in whom medical therapy does not alleviate symptoms, early surgical closure of the VSD is warranted. If circumstances prevent definitive closure, pulmonary artery (PA) banding may be required.

Concentrated formula (24 kcal/oz) allows for growth without relying on vigorous feeding, which preserves growth even with pulmonary overcirculation.

Surgical therapy

Surgical therapy is directed at repairing the defect.

Preoperative details

All imaging studies should be reviewed preoperatively to clearly visualize the defect(s) and to assess for the presence of other intracardiac anomalies. These studies delineate the anatomic substrate and allow appropriate planning for the operation.

All attempts should be made to control CHF and improve the overall condition of the child prior to surgery.

Intraoperative details

VSDs are closed through a median sternotomy approach. Cardiopulmonary bypass using dual caval cannulation (inferior vena cava [IVC] and superior vena cava [SVC]) and cardioplegic diastolic arrest provide a bloodless, motionless field for intracardiac closure. Most VSDs may be closed working through an incision in the right atrium (transatrial approach). The surgeon inspects and repairs the VSD looking through the right atrium, across the tricuspid valve, and into the right ventricle. To visualize defects of the inlet septum, detachment of the septal leaflet of the tricuspid valve may be required.

Conal VSDs may be approached through an incision in the main pulmonary artery (PA) working across the pulmonary valve (transpulmonary approach). Conal VSDs with associated aortic valve insufficiency may be approached through an incision in the ascending aorta, allowing VSD closure and aortic valve repair (transaortic approach). Muscular VSDs may be approached through the ventricular apex (transventricular approach).

Most surgeons close the defect using a synthetic patch (Dacron or polytetrafluoroethylene [PTFE]) sewn to the rightward aspect of the VSD with a running nonabsorbable monofilament suture. Take care to avoid placing deep sutures in the area of conduction tissue to prevent postoperative heart block. Primary closure of VSDs through direct suturing of the defect without using a patch is of historic interest only.

When aortic valve leaflet prolapse with valvular incompetence accompanies conal or perimembranous defects, aortic valve repair (valvuloplasty) is performed. The elongated free edge of the distorted leaflet is shortened, and the leaflet is resuspended against the aortic wall with sutures. Repair of the aortic valve is almost always possible, and aortic valve replacement should be reserved only for extremely damaged valves.

PA pressure is often directly measured to assess for postclosure pulmonary hypertension. If PA pressure is significantly elevated (>50% of systemic arterial pressure), a pressure monitoring line may be left in the PA for postoperative monitoring, if desired.

Associated lesions, such as patent ductus arteriosus or atrial septal defect, should be concomitantly repaired during VSD closure.

Postoperative details

Most children rapidly recover from VSD closure. Extubation usually occurs in the ICU in the hours following surgery. Children requiring postoperative inotropic support, pressor support, or both are weaned within 24 hours postsurgery. Postoperative diuretic therapy is generally needed to return intravascular volume to normal levels.

For the small proportion of children with hemodynamically significant pulmonary hypertension (PA pressure >50-75% of systemic arterial pressure), continued sedation with mechanical ventilation (to maintain normal arterial oxygen and carbon dioxide tensions) and pulmonary vasodilators (eg, nitric oxide, sildenafil) may be used until pulmonary vasculature relaxes within several days after surgery.

After closure, the cardiac rhythm should be observed. Temporary cardiac pacing is necessary in children with transient heart block.

Most children are transferred from the ICU on the first or second postoperative day. Within 48 hours, mediastinal drainage tubes are removed. Many patients are ready for discharge within 4-7 days of surgery.

Follow-up

Patients who have undergone VSD repair should be observed routinely to ensure a return to normal function. Depending on the severity of the preoperative condition and postoperative complications encountered, follow-up care is tailored to the relief of residual CHF and the promotion of normal growth and development. As symptoms of heart failure subside, the patient may be weaned off digitalis and diuretic therapy.

COMPLICATIONS

Section 8 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Potential complications of surgical ventricular septal defect (VSD) closure include infection, postoperative bleeding requiring re-exploration, valve injury (tricuspid, pulmonary, or aortic), pulmonary hypertension with poor cardiac output, atrioventricular (AV) heart block, residual VSD with continued left-to-right shunting, and death.  

Permanent AV heart block occurs in 1% or fewer of children undergoing VSD closure. Care must be taken to correctly identify the position of the defect, since this determines the location of conduction tissue and directs the repair to avoid conduction injury. Transient AV block is treated expectantly with temporary cardiac pacing. When AV conduction does not return (in <1% of patients in the best centers), a permanent pacemaker is needed.

Residual left-to-right shunt from incomplete VSD closure may result from insufficient intraoperative exposure or suture disruption with patch dehiscence. Significant residual shunting is most commonly observed in muscular defects (particularly multiple defects) in which trabeculations decrease visualization of the full extent of the VSD(s). Residual shunting with Qp:Qs greater than 1.5:1 occurs in 2% or fewer of patients and should prompt reoperation.

The mortality rate associated with surgical VSD closure has decreased dramatically with improvements in perfusion, myocardial protection, and postoperative care. The overall surgical mortality rate for patients with isolated VSD is less than 1%, and the mortality rate for low-risk candidates is miniscule. Risk factors for mortality include severe associated noncardiac anomalies, multiple VSDs, and major associated cardiac anomalies.

As noted previously, potential complications of an unrepaired VSD include CHF, irreversible pulmonary vascular disease, bacterial endocarditis, ventricular dilation and dysfunction, and aortic valve dysfunction. A patient with an unrepaired VSD has a moderate-risk lesion for bacterial endocarditis, according to American Heart Association guidelines. Therefore, prophylactic antibiotics are recommended for children with unrepaired VSDs during certain dental, GI, respiratory, and genitourinary procedures.

American Heart Association guidelines consider a repaired VSD a negligible risk lesion for bacterial endocarditis (no greater than the general population). Therefore, prophylactic antibiotics are not recommended for patients more than 6 months after their surgical VSD repair.

OUTCOME AND PROGNOSIS

Section 9 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Long-term results of ventricular septal defect (VSD) repair are favorable. In the absence of pulmonary vascular disease, infants who undergo VSD repair within the first 1-2 years of life are considered cured and demonstrate improved physical development (growth and weight gain), as well as normal long-term ventricular function. Most long-term survivors are asymptomatic and lead normal lives. Exercise tolerance may be diminished. If congestive heart failure and cardiomegaly are well established and repair has been undertaken late in life, postoperative symptoms, including exercise intolerance, are more common. Premature late death is rare (<2.5%) in patients with low preoperative pulmonary vascular resistance. Patients with preoperative pulmonary vascular disease may develop severe, life-threatening pulmonary hypertension.

FUTURE AND CONTROVERSIES

Section 10 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Imaging methods for noninvasive diagnosis of ventricular septal defect (VSD) continue to undergo refinement. Advances may be made in fetal VSD repair as the techniques of intrauterine cardiac diagnosis and intervention are developed. As the genetic predisposition of VSD becomes better understood, prevention may be possible through gene therapy. Newer techniques are under investigation to manipulate the pulmonary vascular bed and pulmonary hypertension. Percutaneous or periventricular techniques with occluding devices to close VSDs, particularly defects located in the muscular septum, are available for perimembranous and muscular VSDs. Catheter occlusion is particularly helpful in trabecular muscular VSDs. Research is being conducted to assess the risks and benefits of catheter-placed VSD occluders for other indications.

MULTIMEDIA

Section 11 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Media file 1:  View of ventricular septal defect just underlying the aortic valve.
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Media type:  CT

Media file 2:  Patch repair technique of a supracristal ventricular septal defect.
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Media type:  CT

REFERENCES

Section 12 of 12

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

1. Roger H. Recherches clinicques sur la communicacion congenitale des deux couers, par inocclusion du septum interventriculare. Bull Acad Med Paris. 1879;8:1074.
2. Eisenmenger VZ. Klin Med. 1898;32:1-28.
3. Muller WH, Damman JF. The treatment of certain congenital malformations of the heart by the creation of pulmonic stenosis to reduce pulmonary hypertension and excessive pulmonary blood flow; a preliminary report. Surg Gynecol Obstet. Aug 1952;95(2):213-9. [Medline].
4. LEV M. The pathologic anatomy of ventricular septal defects. Dis Chest. May 1959;35(5):533-45. [Medline].
5. Becu LM, Burchell HB, Dushane JW, Edwards JE, Fontana RS, Kirklin JW. Anatomic and pathologic studies in ventricular septal defect. Circulation. Sep 1956;14(3):349-64. [Medline].
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Article Last Updated: Nov 15, 2007