Congenital Heart Disease in the Adolescent and Adult

Demographics and Prognosis

Arrhythmias are prevalent in ACHD patients. The frequency of arrhythmias increases with age and disease complexity. Arrhythmia causes morbidity and mortality in adults with CHD and is the most frequent cause for hospital admission in adults with CHD. Patients with CHD with arrhythmia have a worse prognosis than those without.

New arrhythmias in a patient with CHD should prompt a careful evaluation to determine whether there is a hemodynamic cause for the arrhythmia. In many cases worsening ventricular dysfunction, valve dysfunction, or filling pressures can precipitate new rhythm disturbances. Echocardiography may yield information but in some catheterization is required.

The demographics and mechanisms of arrhythmia are very different in ACHD patients compared to adults with acquired heart disease: ACHD patients develop arrhythmia at a much younger age, frequently in their late teens or early 20s for patients with complex forms of CHD. Patients with ACHD are likely to have re-entrant arrhythmia related to surgical scars or around patches although diffuse fibrosis may predispose to arrhythmias as well. Patients with CHD are often intolerant of arrhythmia and in most instances restoration of sinus rhythm is preferred over rate control. In 2014 the Pediatric and Congenital Electrophysiology Society and the Heart Rhythm Society published a comprehensive consensus statement on the management of arrhythmias in adults with CHD. Arrhythmias are discussed further in the sections on individual lesions.

Diagnostic Testing

Resting ECG is indicated in most patients with CHD. Common ECG abnormalities are shown in Table 82.3 . Because rhythm disturbances become more prevalent with increasing age, serial ECG monitoring is needed for patients at high risk for arrhythmia such as those with tetralogy of Fallot (TOF), Ebstein anomaly, Fontan circulation, transposition of the great arteries (TGA), and others.

Ambulatory ECG monitoring is useful to investigate palpitations and to screen for occult arrhythmia in asymptomatic patients. In patients with TOF asymptomatic nonsustained ventricular tachycardia (VT) recorded on Holter monitoring predicts clinical VT. In other CHD lesions, however, the clinical significance of asymptomatic arrhythmias seen on ambulatory ECG remains unknown. Exercise ECG monitoring is useful for patients with exercise-induced symptoms. Implantable loop recorders can be used for patients with infrequent but worrisome symptoms of arrhythmia.

The need for invasive electrophysiology (EP) study with programmed stimulation and electroanatomic mapping should be determined on a case-by-case basis. Inducible sustained VT is a risk factor for clinical VT and sudden death in patients with repaired TOF and is discussed in more detail in the section on Tetralogy of Fallot. The prognostic value of programmed electrical stimulation has not been determined in other forms of CHD and, in some conditions such as TGA, is not of prognostic value.

Types of Arrhythmia

The type of arrhythmia encountered depends both on the native CHD lesion as well as the type of surgical repair (see Table 82.3 ).

Bradyarrhythmia

Tachyarrhythmias

Interatrial Re-Entrant Tachycardia

Interatrial re-entrant tachycardia (IART) is the most common tachyarrhythmia in CHD, accounting for 62% of atrial arrhythmias. The cumulative incidence of IART approaches 50% by age 65 and occurs in a wide variety of CHD lesions. IART can conduct around an anatomic obstacle such as an ASD patch or an atriotomy scar. While it may occur in children, frequency increases by young adulthood as progressive atrial fibrosis contributes to arrhythmogenesis. IART is exceedingly common in patients who have had a Mustard or Senning operation and for those with an atriopulmonary Fontan. In patients who have undergone the atrial switch operation, IART is a dangerous arrhythmia which may convert to polymorphic VT or pulseless electrical activity as the noncompliant interatrial baffles and systemic RV perform poorly at high heart rates. Patients with Fontan circulation also tolerate chronic IART poorly and restoration of sinus rhythm is desirable. Patients with atrial arrhythmias have a 50% increased risk of mortality and double the morbidity compared to patients without atrial arrhythmia. Acute termination of arrhythmia is usually performed with electrical cardioversion after atrial thrombus has been excluded with transesophageal echocardiography (TEE) or gated CCT. Pace termination or pharmacologic cardioversion can be performed in selected patients. Anticoagulation is required for at least 4 weeks following cardioversion.

Rhythm control is usually preferred over rate control for adults with CHD and IART. Catheter ablation is often effective and used as first-line therapy when IART is recurrent. Ablation should be performed by an electrophysiologist with experience in CHD as the mechanisms of re-entry are due to surgical patches and unconventional anatomy not typically seen in acquired heart disease. Trans-baffle punctures are often required in patients with Mustard/Senning operations or Fontan circulation where the majority of patients have multiple IART circuits.

Medical therapy is a useful adjunct to catheter ablation or can be used when ablation is unsuccessful. AV nodal blockade with beta-blockers or calcium blockers is reasonable to prevent rapid ventricular response. Anti-arrhythmic drug choice must be tailored to the patient’s underlying congenital anatomy and consider risk factors for pro-arrhythmia such as ventricular dysfunction or QTc prolongation ( Fig. 82.2 ). Sotalol and dofetilide are often preferred in patients with complex CHD. Amiodarone has considerable cumulative toxicity so is usually not a preferred first-line antiarrhythmic in younger patients but is sometimes required for patients with ventricular dysfunction.

Which patients with atrial arrhythmia and CHD require long-term anticoagulation remains an area of active investigation. Risk models such as CHA ₂ DS ₂ -VASc are not validated in CHD and should not be relied upon because CHD patients have a much higher rate of thromboembolism than similarly aged patients with acquired heart disease, even in the absence of conventional risk factors. Patients with Fontan circulation and IART should receive long-term anticoagulation. Patients with atrial arrhythmia and complex CHD should be considered for long-term anticoagulation as well. Both vitamin K antagonists and direct oral anticoagulants have been used successfully in adult patients with CHD.

Ventricular Tachycardia and Sudden Death (see Chapter 70 , Chapter 70 )

Sudden death is the second most common cause of cardiac death in adults with CHD following heart failure, and accounts for approximately 20% of death in patients with CHD, occurring at a rate of ∼0.1% per patient year. Patients with TOF, TGA with a systemic RV, Fontan circulation, Eisenmenger syndrome, and complex forms of CHD are at the highest risk for ventricular arrhythmias and sudden cardiac death. Fortunately, the frequency of sudden death may be declining due to improved risk stratification, implantable cardioverter defibrillators (ICDs), and improvements in surgical technique (such as earlier definitive surgical repair and avoidance of ventriculotomies). ^, Ventricular arrhythmias are often macroreentrant scar-based arrhythmias. Discrete or diffuse replacement fibrosis also contributes to ventricular arrhythmia.

Risk stratification to predict which patients are at risk for sudden death is challenging. Patients with a systemic LV and severe systolic dysfunction are thought to be high risk. A combination of clinical, ECG, and imaging parameters identify high-risk patients with repaired TOF and is discussed in detail in the section on Tetralogy of Fallot. Invasive EP studies further identify patients with repaired TOF but have not been shown to be predictive in other forms of CHD.

Secondary prevention ICDs are appropriate for patients with clinical sustained VT or aborted sudden cardiac death. Antiarrhythmic drugs may be adjunctive and catheter ablation can reduce the risk of ICD shocks. Results of catheter ablation for VT in repaired TOF are discussed separately.

Pacemakers and Implantable Defibrillators (see Chapter 69 )

Pacemakers and ICDs are required in many patients with CHD. Indications for pacemakers are sinus node dysfunction and heart block. Indications for primary and secondary prevention ICDs are shown in Table 82.6 .

Unfortunately, patients with CHD are at high risk for device complications such as lead fractures or device infections, which occur in up to 26% of adults with CHD. Both appropriate and inappropriate shocks are common in ACHD patients with ICDs. In a meta-analysis, appropriate shock rate was 22% at 3.3 years and inappropriate shock rate was 35% at 4.3 years follow-up, each higher than is seen in acquired heart disease. Improvements in device algorithms and programming may reduce the risk of inappropriate shocks in contemporary cohorts.

Device implantation can be difficult in patients with surgically manipulated or variant venous anatomy (such as following Mustard/Senning procedures). Pacemakers should be epicardial in patients with intracardiac shunts, single ventricle, or ventricular leads in Fontan circulation. Cardiac resynchronization leads may be technically difficult due to variation in the location of the coronary sinus (CS) os. A proposed algorithm for cardiac resynchronization therapy (CRT) in CHD is shown in Fig. 82.3 .

Because of the higher risk of device complications, both appropriate and inappropriate shocks, and the challenges with device implantation, the risk-benefit ratio of devices needs to be weighed carefully and in conjunction with ACHD providers and electrophysiologists experienced in CHD.

Epidemiology

Despite continued improvements in outcomes for those born with CHD, most adults with CHD, particularly for those with moderate or complex CHD, die from cardiac causes. Heart failure remains a major source of morbidity and the dominant cause of death for adults with CHD in the modern era, accounting for up to 40% of the ACHD mortality.

The rate of heart failure hospitalizations among adults with CHD is increasing at a rapid rate. Hospitalizations for adults with CHD is associated with longer length of stay, high resource utilization, and poor in-hospital and long-term outcomes. Heart failure is most common in patients with high anatomic or physiologic complexity including single ventricle anatomy, systemic RV, PH, and cyanosis. However, even patients with simple forms of CHD are at increased long-term risk of heart failure.

Clinical Features

The clinical presentation of heart failure in patients with CHD is diverse. Typical symptoms such as pulmonary congestion, edema, and dyspnea on exertion may not be present. Often arrhythmia, hypoxemia, or exertional fatigue may be the presenting symptoms of heart failure in patients with CHD. Many patients with CHD have adapted to their lifelong cardiac condition and may under-report functional limitations. Cardiopulmonary exercise testing is useful to elicit sub-clinical deterioration, even in patients who report that they feel well. Patients with CHD and heart failure often have elevated biomarkers. Elevations in brain natriuretic peptide (BNP), troponin, and other biomarkers are associated with heart failure and poor outcomes in adults with CHD.

Pathophysiology

The etiology and pathophysiology of heart failure in adults with CHD is often quite different from that of adults with acquired cardiovascular disease. The majority of heart failure in adults with acquired cardiovascular disease is secondary to left ventricular systolic or diastolic dysfunction; this is not true in adults with CHD. Adults with CHD are more likely to have a single ventricle, systemic RV, associated pulmonary vascular disease, residual shunt, or residual outflow obstruction as an underlying etiology of heart failure.

The pathophysiologic basis of heart failure differs depending on the underlying lesions. Volume loading from shunts and valvular regurgitation cause ventricular dilation and, if untreated, ventricular dysfunction. Residual outflow obstruction can result from sub-valvular or valvular stenosis as well as peripheral arterial narrowing, such as aortic coarctation. Obstructive lesions can induce ventricular hypertrophy and dysfunction.

Patients with a systemic RV (such as those with D-loop TGA treated with an atrial switch procedure or those with L-loop TGA) are at high risk for ventricular dysfunction. The systemic RV is predisposed to systolic dysfunction due to unfavorable myocardial fiber orientation, nonconical shape, coronary supply-demand mismatch, and volume loading from tricuspid regurgitation.

Heart failure is exceedingly common in adults who have undergone the Fontan operation; transplant-free survival is less than 70% 25 years after the Fontan operation and most patients develop heart failure by age 40. The mechanisms for heart failure after the Fontan operation are multifactorial and incompletely understood. Not all patients have overt ventricular or valvular dysfunction. Fontan failure is characterized by chronically elevated central venous pressure, low cardiac output, cyanosis due to collaterals, ascites, and cirrhosis.

Cardiac Resynchronization

CRT via multi-site pacing is appropriate for patients with a systemic LV, spontaneous or pacing-induced left bundle-branch block, and heart failure. The role of CRT in other forms of CHD is not as well established.

Patients with a systemic RV (particularly those with L-loop TGA) have a high incidence of heart block as well as frequent need for ventricular pacing. Multiple observational studies suggest benefit of CRT in patients with a systemic RV, although the data are generally retrospective and uncontrolled. Placing CRT leads is technically more difficult in patients with a systemic RV due to variability in the location of the CS os, variant coronary vein anatomy, and the presence of surgical interatrial baffles. It is reasonable to consider placement of epicardial multi-site pacing leads in selected patients if they are going for cardiac surgery for other indications.

The benefit of CRT in patients with single ventricle anatomy following the Fontan operation is not well established. Additionally, multi-site pacing requires epicardial lead placement.

Transplantation

Patients with CHD and heart failure refractory to medical therapy should be considered for heart transplantation. Since 2000, the number of ACHD patients listed for transplantation and ultimately transplanted has doubled. Adult CHD patients account for more than 4% of adult heart transplantations done in the United States.

Compared to patients with acquired heart failure, CHD patients listed for heart transplantation are younger, more likely to have a prior sternotomy, less likely to have coronary artery disease, and less likely to have a left ventricular assist device. Alloimmunization secondary to prior transfusions or homograft implantation can prolong waitlist times, require desensitization, or make some patients ineligible for transplantation. Many patients with CHD have important comorbidities such as cirrhosis, chronic kidney disease, restrictive lung disease (as a consequence of prior chest surgery), or pulmonary vascular disease which may make them high-risk, or even ineligible for cardiac transplantation. For all these reasons, many patients with CHD and advanced heart failure are never listed for heart transplantation. Even those patients who are ultimately listed for transplantation are more likely to be delisted or die without transplantation than patients with acquired cardiovascular disease.

Due to the high complexity and prevalence of comorbidities in CHD patients with advanced heart failure, a multidisciplinary team consisting of ACHD specialists, advanced heart failure specialists, and cardiac surgeons with experience in both congenital and transplant surgery should evaluate all ACHD patients considered for transplantation. Necessarily, this process should take place at an ACHD specialty center.

Patients with CHD are listed at UNOS Status 4 in the allocation system adopted in 2018. They share status urgency with ambulatory patients with a left ventricular assist device, patients with cardiac amyloidosis, and those awaiting re-transplantation. Many of the criteria used to justify higher-urgency status, such as poor hemodynamics, inotropic support, or mechanical circulatory support may not be applicable to patients with ACHD. Therefore, patients with ACHD may require an exception to be listed at higher urgency in order to reflect their acuity and higher waitlist mortality.

Patients with CHD have high operative risk which is reflected by increased in-hospital and 1-year mortality following transplantation. This early risk is mitigated by low late graft failure and mortality compared to those with acquired heart disease so that long-term survival is not lower for ACHD patients undergoing transplantation ( Fig. 82.4 ). ^, For this reason, organ allocation to ACHD patients results in acceptable utility of donor hearts. Because of the high surgical risk and complexity of transplant in CHD, transplant should be performed at specialty ACHD centers. When performed at high-volume ACHD transplant centers, outcomes are improved.

Subacute Bacterial Endocarditis

Patients with ACHD have an increased risk of developing subacute bacterial endocarditis (SBE), and this is associated with significant morbidity and mortality (see Chapter 80 ). The most common pathogens responsible for SBE include Streptococcus viridans, Staphylococcus species, and Enterococcus species. Antibiotic prophylaxis is recommended prior to dental procedures for ACHD patients with high-risk characteristics, which include: (1) prior episodes of SBE, (2) prosthetic valves (including transcatheter), (3) valve repair using a prosthetic ring, (4) residual intracardiac shunts adjacent to prosthetic material, (5) cyanotic CHD, (6) any CHD repaired with prosthetic material up to 6 months after the procedure or lifelong if residual shunt or valvular regurgitation remains, and (7) for cardiac transplant recipients who develop cardiac valvulopathy. In a registry of over 14,000 ACHD patients, the incidence of SBE was 1.33 cases per 1000-person years. Valve-containing prosthetics were found to be an important independent risk factor for SBE, both short and long term after implantation, whereas non-valve-containing prosthetics (including valve repair) are associated with greater risk only in the short term (<6 months) after implantation ( Fig. 82.5 ). ACHD patients should be educated about symptoms of SBE and the importance of good oral hygiene and of obtaining blood cultures before starting antibiotic treatment in situations with concerning features for infection.

Benefits of Physical Exercise

Virtually all patients with CHD should be encouraged to be physically active, exercise, and maintain physical fitness. Physical activity promotes cardiovascular and mental health; people who exercise regularly have an improved quality of life, better exercise capacity, and are less likely to suffer from obesity or type 2 diabetes. Even patients with complex CHD, such as Fontan circulation, derive benefits from regular physical exercise.

Despite the benefits of exercise, physicians, parents, or patients may have concerns about the risk of sudden death with exercise and restrict physical activity or competitive sports. The risk of sudden death during exercise is very low for adults with CHD and observational studies do not suggest that exercise restriction reduces the risk of sudden death, perhaps because the majority of sudden death in patients with CHD occurs at rest, not with exercise. At least in part due to these exercise restrictions, patients with CHD have lower levels of physical activity than patients without CHD and only 30% of patients with CHD achieve the recommended levels of physical activity.

Individualized Exercise Programs

Patients with CHD require individualized counseling regarding exercise recommendations or restrictions. In general, patients with CHD have lower exercise capacity than patients without CHD and there is considerable heterogeneity across different diagnoses ( Fig. 82.6 ). Patients with moderate or complex anatomy or physiology may benefit from formal exercise testing to establish baseline exercise capacity and demonstrate safety of exercise. Patients with high-risk anatomy or physiology should be discouraged from participating in high-intensity sports and counseled toward lower-intensity physical activity ( Table 82.8 ).

Low-risk patients can begin a training program at approximately 70% maximal predicted heart rate at least three times per week (totaling 150 minutes/week) and increase intensity or duration over time.

Competitive Sports

There are important differences between competitive sports and recreational exercise. In competitive sports, participants cannot reliably self-regulate effort and require high-intensity burst efforts imposed by coaches or playing conditions. For these reasons, competitive sports are thought to pose greater risk.

The AHA and ACC published a consensus statement on eligibility for participation in competitive sports in 2015. Sports are graded in terms of their static and dynamic components and appropriateness for competition depends on the native anatomy and the presence of residual sequelae following repair. In many patients, pre-participation stress testing can provide useful information about the patient’s exercise capacity, hemodynamics with exercise, and the presence of exercise-induced arrhythmias that can help guide decision making. Particularly for teenagers and adults shared decision making is often required following a detailed conversation about risks.

Anatomic Description and Prevalence

There are multiple locations for interatrial communications, and a detailed understanding of the atrial septal anatomy is needed. Fig. 82.8 illustrates various locations of ASDs. The prevalence of ASD is 0.88 per 1000 adults. The most common type of ASD is a secundum ASD ( Fig. 82.9 ), which is a true deficiency in the atrial septum, in the region of the fossa ovalis. This should be differentiated from a patent foramen ovale (PFO), which is persistence of patency of the flap valve of the fossa ovalis (not associated with right-sided cardiac dilation) and persists in up to 25% of adults. Primum ASDs may be considered in the spectrum of AVSDs ( Fig. 82.10 , Video 82.2A , B ) and involve a deficiency in the region of the AV valves and are associated with a cleft in the mitral valve. Sinus venosus defects occur in the sinus venosus septum posterior to the true atrial septum and usually involve anomalous right-sided pulmonary venous return ( Fig. 82.11 ). CS defects (also called unroofed CSs) are rare and involve direct communication of the CS and the LA due to complete or partial unroofing of the CS and are often accompanied by a persistent left-sided SVC.

Patients may also have anomalous pulmonary venous connections not associated with an ASD, known as partial anomalous pulmonary venous connection (PAPVC). PAPVC may be associated with either right- or left-sided pulmonary veins which can have several possible anomalous connections, with the most common being a left upper pulmonary vein to an ascending vertical vein into the brachiocephalic vein or the right upper pulmonary vein draining to the SVC ( Fig. 82.12 ). In the latter case, careful attention should be paid to ensure that there is not an associated sinus venosus defect. When the right-sided pulmonary veins connect to the inferior vena cava (IVC), this is called a scimitar vein. Isolated PAPVC involving a single pulmonary vein may cause mild degrees of right heart overload, but rarely require surgical correction.

Clinical Features

It is not uncommon for adults to have an ASD incidentally discovered at the time of imaging for unrelated issues. Symptoms, when they occur, most commonly include exercise intolerance, palpitations, or dyspnea with exertion. Supraventricular arrhythmias develop by 40 years of age in about 10% of patients and become increasingly prevalent with advancing age. The presence of cyanosis should alert one to the possibility of shunt reversal and Eisenmenger syndrome or, alternatively, to a prominent eustachian valve directing the inferior vena caval flow to the LA via a secundum ASD or sinus venosus defect of the inferior vena caval type. Pulse oximetry at rest and during exercise is recommended for evaluation of adults with unrepaired or repaired ASD with residual shunt to determine the direction and magnitude of the shunt.

The classic physical examination of an ASD is a wide, fixed splitting of the second heart sound, which is due to prolonged RV ejection and increased PA capacitance, which, in turn, delay pulmonary valve closure. Pulmonary flow murmurs are common. The ECG commonly displays a rightward QRS axis and an incomplete right bundle branch block (RBBB). The classic chest radiograph features are of cardiomegaly (from right atrial and right ventricular enlargement), and dilated central pulmonary arteries with pulmonary congestion. Cardiac imaging is essential in determining the anatomy of the atrial septum and pulmonary venous drainage. TTE is the initial imaging test, however, other imaging modalities, such as TEE, CMR, and CCT may be needed to confirm the anatomy. The 2020 Appropriate Use Criteria guidelines rate these modalities as always appropriate for the evaluation prior to planned surgical repair for sinus venous defects or for patients with a change in clinical status or new symptoms.

Repairs

When an ASD is discovered in an adult, if there is any degree of right heart dilation associated with symptoms, closure should be considered. It is important to verify the direction of the shunt as left-to-right. The next step is to verify that the PVR is less than ⅓ the SVR, the PA systolic pressure is less than 50% systemic, there is right heart enlargement, and the Qp/Qs is at least 1.5:1. The majority of secundum ASDs may be closed percutaneously ( Fig. 82.13 ), however, surgical closure is required for sinus venosus defects, primum ASDs, or CS septal defects. It is reasonable to close an ASD in an asymptomatic patient with right heart enlargement (AHA/ACC Class IIa recommendation, level of evidence C-LD). If invasive hemodynamic assessment confirms significant elevations in PVR and/or pulmonary pressure, collaboration between ACHD and PH providers is important (see section on Eisenmenger syndrome).

Surgical closure is typically performed using a patch of autologous pericardium or synthetic material with an open sternotomy and cardiopulmonary bypass. The operative mortality is low, however, postoperative complications of post-pericardiotomy syndrome or atrial arrhythmias may occur. Special attention must be paid to those defects with partial anomalous pulmonary venous drainage, as redirecting the pulmonary venous flow may result in pulmonary vein stenosis. In patients with primum ASDs, care must be taken in closing the mitral valve cleft to avoid mitral stenosis or residual regurgitation.

Transcatheter closure is now widely accepted as an alternative to surgical repair for the majority of secundum ASDs. Several devices are available and range in size and configuration. Adequate rims of the defect must be demonstrated to ensure safe transcatheter closure. Post-procedural complications include atrial arrhythmias, heart block, thrombus formation on the device, and rarely device mobilization or erosion.

Long-Term Outcomes and Complications

Patients who undergo ASD repair prior to the age of 25 years have favorable outcomes. However, surgical repair does not provide proven benefit in reducing arrhythmia burden in older adults. Following closure, patients with significant residual shunt, valvular or ventricular dysfunction, arrhythmias, and/or PH should be followed at regular intervals with TTE. The imaging recommendations for patients following transcatheter ASD closure are dictated by the specific manufacturer, but in general, TTE is performed at 1 week, 1 month, and then annually for at least 5 years following closure. Any patient who has had a transcatheter ASD device placed who presents with chest pain should have an urgent evaluation to rule out device erosion, which occurs in 1 in 1000 cases.

Patients with ASD and elevated PVR require closely monitored management as PAH can progress even after ASD closure.

Anatomic Description and Prevalence

AVSDs are a spectrum of lesions that involve deficiencies of the AV septum, often accompanied by anomalies of the AV valves. AVSDs are the result of failed fusion of the endocardial cushions, and comprise up to 5% of CHD. These include primum ASDs, partial or complete AV canal defects ( Fig. 82.14 ). Complete AVSDs are characterized by both an atrial and ventricular level defect with a common AV valve, usually comprised of five leaflets. A partial AVSD does not have a VSD component, and almost always has a cleft in the anterior mitral valve leaflet. A unique anatomic feature in patients with AVSD is elongation of the LVOT, due to the aortic valve being displaced anteriorly. This results in a scooped-out appearance of the ventricular septum and a shortened LV inlet, creating a “goose neck” appearance ( Fig. 82.15 ). The severity of the defect is dictated by several factors including size of the shunt, extent of AV valve abnormalities, size discrepancy of the ventricle, and presence of additional anomalies, including LVOT obstruction.

Clinical Features

The great majority of patients with AVSD undergo repair in childhood. Older patients with large AVSDs which have not been repaired early in life usually develop irreversible pulmonary vascular disease and Eisenmenger syndrome, precluding complete repair. More commonly, adults with a history of AVSD repair in childhood present with symptoms from residual left AV valve regurgitation and stenosis, LVOT obstruction, or atrial arrhythmias.

Surgical Repairs

Indications for surgical intervention of AVSD in adults are similar to those for ASD closure. These include a net left-to-right shunt (Qp:Qs ≥1.5:1), PA systolic pressure less than 50% systemic, and PVR less than one third systemic. Pre-operative cardiac catheterization may be required to assess for PH. For adults with prior repair, left AV valve regurgitation is the most common reason for later surgical reintervention.

Long-Term Outcomes and Complications

Survival after AVSD defects repair is good, yet reoperation for left AV valve disease and LVOT obstruction remains significant. Other late complications include patch dehiscence or residual septal defects and development of complete heart block. Those adults with repaired AVSD and any degree of PH must be followed closely.

Anatomic Description and Prevalence

VSDs are the most common form of CHD, and the reported incidence of isolated VSDs varies widely, from 1.5 to 53 per 1000 live births. There are several classification schemes used to describe VSDs ( Table 82.10 ). Fig. 82.16 demonstrates the locations of VSDs.

Clinical Features

Many isolated muscular and perimembranous VSDs are small and close spontaneously in childhood. However, there are several clinical presentations of VSDs in adults ( Fig. 82.17 , Video 82.3 ). Patients living with small, restrictive VSDs are usually asymptomatic with a harsh holosystolic murmur on exam. Continuous wave Doppler through these defects reveals a high velocity, often greater than 5 msec, which confirms the pressure-restrictive physiology. In this case, the left-to-right shunt is minimal, and there is usually not left ventricular dilation. Other adults may present with prior VSD surgical repair in childhood, some of whom have residual patch margin leaks. A small number of adults will present with moderate- or large-size VSDs which have not undergone closure. These patients must be assessed for elevated PVR and the presence of Eisenmenger syndrome.