ReviewAdult Congenital Heart Disease: A Growing EpidemicPablo Ávila, MD, Lise-Andr!ee Mercier, MD, Annie Dore, MD, François Marcotte, MD,

François-Pierre Mongeon, MD, MS, Reda Ibrahim, MD, Anita Asgar, MD, Joaquim Miro, MD,Gregor Andelfinger, MD, Blandine Mond!esert, MD, Pierre de Guise, MD, Nancy Poirier, MD, and

Paul Khairy, MD, PhDMontreal Heart Institute Adult Congenital Center, Universit!e de Montr!eal, Montreal, Quebec, Canada

ABSTRACTMedical and surgical breakthroughs in the care of children born withheart defects have generated a growing population of adult survivorsand spawned a new subspecialty of cardiology: adult congenital heartdisease. The prevalence of adult congenital heart disease is escalatingat a rampant rate, outpacing the relatively static prevalence of pedi-atric congenital heart disease, because adults now surpass children innumbers by a ratio of 2:1. As such, congenital heart disease can nolonger be considered primarily a pediatric specialty. Most congenitalheart defects are not curable and require lifelong specialized care.Health care systems worldwide are challenged to meet the uniqueneeds of this increasingly complex patient population, including thedevelopment of supraregional centres of excellence to providecomprehensive and multidisciplinary specialized care. In this review,we explore the incidence and prevalence of congenital heart diseaseand their changing patterns, address organization and delivery of care,highlight the importance of appropriate training and dedicatedresearch, summarize the high burden of health care resource utiliza-tion, and provide an overview of common issues encountered in adultswith congenital heart disease.

R!ESUM!ELes avanc!ees m!edicales et chirurgicales dans la prise en charge desenfants n!es avec des malformations cardiaques ont g!en!er!e un nombrecroissant de survivants adultes et ont donn!e naissance à une nouvellesous-sp!ecialit!e de la cardiologie : la cardiopathie cong!enitale chezl’adulte. La pr!evalence des adultes atteints de cardiopathie con-g!enitale s’amplifie à un rythme effr!en!e, d!epassant la pr!evalence rel-ativement stable des cardiopathies cong!enitales p!ediatriques, puisqueles adultes d!epassent maintenant en nombre les enfants avec un ratiode 2 : 1. En tant que telle, la cardiopathie cong!enitale ne peut plus êtreconsid!er!ee comme !etant essentiellement une sp!ecialit!e p!ediatrique.La plupart des anomalies cardiaques cong!enitales ne sont pas cur-ables et n!ecessitent des soins sp!ecialis!es à vie. Les systèmes de sant!edu monde entier sont amen!es à r!epondre aux besoins particuliers decette population de patients de plus en plus complexe, y compris par led!eveloppement de centres d’excellence suprar!egionaux afin de fournirdes soins sp!ecialis!es d’ensemble et multidisciplinaires. Dans cetterevue, nous examinons l’incidence et la pr!evalence des cardiopathiescong!enitales et leurs particularit!es changeantes, nous abordons l’or-ganisation et la prestation des soins, mettons en !evidence l’impor-tance d’une formation appropri!ee et d’une recherche d!edi!ee,r!esumons la charge consid!erable de l’utilisation des ressources dessoins de sant!e, et nous fournissons un aperçu des problèmes habituelsrencontr!es chez les adultes atteints de cardiopathie cong!enitale.

Congenital heart malformations are the most common birthdefects and the leading cause of infant mortality.1 Althoughseveral studies have attempted to quantify the incidence ofcongenital heart disease, generating accurate estimates iscomplicated by nonstandardized definitions of qualifying pa-thologies, nonuniform screening methods, and geographicvariability. Notwithstanding these limitations, recent

estimates suggest that the incidence of congenital heart disease(excluding patent foramen ovale and bicuspid aortic valve) isin the order of 7 to 10 per 1000 live births, with moderate andsevere forms afflicting 3 per 1000 newborns.2-4 Consideringthat there are approximately 138 million live births per yearworldwide yields an estimated 1 million newborns withcongenital heart disease every year. These rates have remainedrelatively constant since 2011.5

In developed countries, a shift toward a greater proportionof simpler defects has been reported, which might reflectenhanced sensitivity in detecting milder forms of congenitalheart disease combined with a reduction in the incidence ofnewborns with the most severe defects because of pregnancytermination on prenatal detection.2

Canadian Journal of Cardiology 30 (2014) S410eS419

Received for publication June 7, 2014. Accepted July 23, 2014.

Corresponding author: Dr Paul Khairy, Montreal Heart Institute AdultCongenital Center, Montreal Heart Institute, 5000 Belanger St E, Montreal,Quebec H1T 1C8, Canada. Tel.: þ1-514-376-3330 "3800; fax: þ1-514-593-2581.

E-mail: paul.khairy@umontreal.caSee page S417 for disclosure information.

http://dx.doi.org/10.1016/j.cjca.2014.07.7490828-282X/! 2014 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Prevalence of Congenital Heart DiseaseMost patients born with moderate or severe forms of

congenital heart disease in the 1950s and earlier died beforereaching adulthood, with the highest mortality during the firstweek of life.6 Remarkable advances in diagnostic methods,medical management, interventional techniques, congenitalheart disease surgery, and perioperative care have led to his-torical shifts in population demographic characteristics, andadults now outnumber children with congenital heart defectsby a ratio of 2:1.7-9 Improved survival has been driven by areduction in mortality in the youngest age strata, particularlyin those with severe forms of congenital heart disease (Fig. 1).7

From 1987 to 2005, a > 30% reduction in mortality wasreported among patients with congenital heart disease at large,with a 67% mortality reduction in children with complexdisease.7 More than 85% of children born with heart defectsare now expected to survive to adulthood and continue tothrive.10-12 Consequently, the population with congenitalheart disease is aging. For example, the median age of patientswith severe defects was 11 years in 1985 compared with 17years in 2000.13 In 2000, the median age of adults withcongenital heart disease was 40 years, with a median age of 29in those with severe defects.13 From 1987 to 2005, the me-dian age at death increased by 15 years, from 60 to 75 years,and the median age at death in those with severe defectsincreased from 2 to 23 years.7

In amanner similar to incidence, estimating the prevalence ofcongenital heart disease is fraught with assumptions and subjectto limitations. Prevalence is defined as the number of livingsubjects with a particular disease during a specific time frame.Birth prevalence underestimates the true burden of congenitalheart disease by not capturing those in whom the diagnosis isestablished afterward. Prevalence estimated at a later time ex-cludes those who died before the assessment, thereby differen-tially underrepresenting higher-fatality lesions, and potentiallyomitting defects that resolve spontaneously. For example, up totwo-thirds of ventricular septal defects diagnosed at birth

spontaneously close within the first years of life and will not bepresent in adulthood, whereas other forms of congenital heartdisease, such as atrial septal defects, Ebstein anomaly, andcongenitally corrected transposition of the great arteries mightgo unrecognized until adulthood. Furthermore, prevalence es-timates might not consider other factors that affect global diseaseepidemiology, such as migration and population mobility.

A Quebec population-based study estimated that, in theyear 2010, the prevalence of congenital heart disease in adults(18 years of age and older) was 6.1 per 1000.9 Similar rateswere projected in a recent systematic review.14 Extrapolatingthis statistic to the general population, it might be estimatedthat there are > 100,000 adults with congenital heart diseasein Canada, 1 million in the United States,15 and 1.8 millionin Europe.16 It is also noteworthy that the prevalence ofcomplex congenital heart disease in adults has been steadilyincreasing (eg, by 85% from 1985 to 2000), unlike therelatively stable prevalence of complex congenital heart diseasein children (Fig. 2).13 By 2010, adults accounted for 60% ofpatients with complex congenital heart disease.9

Organization and Delivery of CareAlthough the provision of care for children with congenital

heart disease is well established in developed countries, clinicalservices for adults are comparatively scarce.17-19 To attend tothe progressive increase in the number of adults withcongenital heart disease and the increasing complexity of theirpathologies, specialized adult congenital heart centres haveemerged in several countries, with increasing volume of ac-tivities (Fig. 3).

Canada assumed a leadership role in establishing recom-mendations for optimal organization and delivery of care. In1991, the Canadian Adult Congenital Heart (CACH)network was established as the first national society dedicatedto the care of adults with congenital heart disease (www.cachnet.ca). The Canadian Cardiovascular Society, in collab-oration with the CACH network, formed a panel of experts in1996 to discuss the needs of adults with congenital heartdisease and provide recommendations for referral to special-ized centres. The first management guidelines were presentedat the Canadian Cardiovascular Congress in Montreal in1996, published in the Canadian Journal of Cardiology in1998,20 and subsequently updated in 200121 and 2009.22

Similar proposals emerged from the 32nd Bethesda Confer-ence in 2000, which focused on the need for health careprofessionals, patients, and governing agencies to developstrategic plans to improve access to and delivery of care for theadult with congenital heart disease.23 This call to action wasfollowed by more specific recommendations from the Amer-ican College of Cardiology/American Heart Association andthe European Society of Cardiology (ESC).24,25

Current management guidelines suggest that approxi-mately half of the adult population with congenital heartdisease stand to benefit from specialized care within adultcongenital heart centres. Such care is generally recommendedfor the initial assessment of adults with known or suspectedcongenital heart disease, follow-up of patients with moderateand severe lesions, cardiac surgical and nonsurgical in-terventions, and risk assessment and support for pregnancyand noncardiac surgery.17,20,22,25-27

Figure 1. Distribution of age at death in patients with congenital heartdisease in 1987-1988 and 2004-2005. Histogram bars depict theproportion of all deaths (x-axis) according to age at death (y-axis) in ourcohort of patients with congenital heart disease in the first (1987-1988; left graph) and final (2004-2005; right graph) years of obser-vation. Bold black curves with diamonds represent the correspondingage at death distribution in the general Quebec population during thesame periods of observation. Reproduced from Khairy et al.7

Ávila et al. S411ACHD: A Growing Epidemic

Recommended personnel and services for regional adultcongenital centres are summarized in Table 1.25 In short,centralized care within regional centres should be provided by amultidisciplinary team comprised of cardiologists with expertisein adult congenital heart disease, including imaging, arrhythmiamanagement,28 interventional cardiology, and high-risk ob-stetrics, congenital heart surgeons, perioperative care, and psy-chosocial support.17,25,26 Estimates regarding the ideal numberof regional adult congenital centres have varied between 1 per

2-10 million inhabitants,17,21 which translates to up to 17specialized centres in Canada, 150 in the United States, and 365in Europe.29 This figure balances factors such as ease of accessand centralization of resources, considering that improved out-comes are proportional to volume of activity and experience.30

Although the recommended number of specialized centres hasbeen achieved in Canada (ie, 17 centres are registered within theCACH network), most countries in the developed world fallshort of this target. For example, in the United States, 108

Figure 2. Number and proportion of adults and children with (A) all forms of congenital heart disease (CHD), and (B) severe CHD in 1985, 1990,1995, and 2000. Reproduced from Marelli et al.13

Figure 3. Number of patients followed at the Montreal Heart Institute Adult Congenital Centre over time. A > 7-fold increase in the number of adultswith congenital heart disease was observed over a 15-year period.

S412 Canadian Journal of CardiologyVolume 30 2014

self-declared adult congenital heart centres with variable volumesof activity and availability of resources are listed on the AmericanCongenital Heart Association Web site (www.achaheart.org).

An adequate ratio of specialized adult congenital centres isno guarantee for optimal care. A larger issue that plagues thefield of congenital heart disease is the relatively small pro-portion of qualifying patients who actually receive specializedadult-oriented care. For example, a Canadian study found that< 25% of adults with congenital heart disease are followed byspecialized centres and that waiting times to access servicesexceed published recommendations.31 These sobering statis-tics have prompted numerous educational initiatives to raiseawareness about the need for lifelong care and have incitedresearch studies into factors associated with gaps in care andimpediments to long-term follow-up.32,33 Common barriersto transfer from pediatric-to adult-oriented health care includeinadequate knowledge regarding the need for such care, adearth of accessible competent adult care providers, andemotional attachment of patients and families to their pedi-atric caregivers and vice-versa.34,35 Lending further credenceto the notion that specialized adult congenital centres withmultidisciplinary expertise offer the best prospects forimproving outcomes, a recent population-based study

concluded that referral to such a centre is associated with asignificant reduction in all-cause mortality (Fig. 4).36

Training and ResearchAn important element in optimizing outcomes is the devel-

opment of training programs to meet workforce requirementsand provide qualified, consistent, and comprehensive care.37

Exposure of adult cardiology trainees to adult congenital heartdisease didactic and clinical experience varies widely, reflectingthe fact that few programs offer advanced training in this sector ofcardiology.38 Surveys suggest that only approximately 25% ofcardiologists who care for adults with congenital heart diseasehave received formal training in this discipline.31,37

The United States is the first country to officially recognizethe legitimacy of adult congenital heart disease as a separatesubspecialty of cardiology.39 In September 2012, the Amer-ican Board of Medical Subspecialties approved a specializedcertification examination via the American Board of InternalMedicine. The first examination is planned for 2015. Pedi-atric or adult cardiologists require a minimum 2-year fellow-ship within recognized adult congenital training centres toqualify. The ESC, with its working group on grown-upcongenital heart disease, is poised to follow suit.40 Canada iscurrently contemplating recognizing adult congenital heartdisease as an area of focused competence via a Diploma of theRoyal College of Physicians and Surgeons of Canada(DRCPSC). While details remain to be determined, aDiploma of the Royal College of Physicians and Surgeons ofCanada typically requires 1-2 years of additional training byRoyal College-accredited programs and is competency-based,with assessment through a summative portfolio.

Another critically important element required to advancethe care of adults with congenital heart disease is well-designedresearch. Over the past decade, significant strides have beenachieved in coordinating research efforts and creating dedi-cated infrastructures.41 A critical mass of patients and in-vestigators has enabled a new era of multicentre research withmore exacting standards. Several networks and organizationshave emerged, some focused on multicentre research as theirmain objective, with others providing a supportive environ-ment to facilitate research. These include, but are not limitedto, the International Society for Adult Congenital Heart Dis-ease (www.isachd.org), CACH network, ESC (www.escardio.org), Japanese Circulation Society (www.j-circ.or.jp/english),Society of Thoracic Surgeons (www.sts.org), Congenital HeartSurgeons’ Society (www.chss.org), and the Adult CongenitalHeart Association. In the Netherlands, the InteruniversityCardiology Institute and Heart Foundation developed a highlyproductive national registry and DNA bank of patients withcongenital heart disease, named CONgenital CORvitia(CONCOR; www.concor.net/en).42 In North America, anAlliance for Adult Research in Congenital Cardiology wasfounded in 2006 to foster collaborative research, advanceknowledge, and improve outcomes (www.aarcc.net).

Health Care Resource UtilizationDespite surgical repair, most forms of congenital heart

disease are associated with sequelae and long-term complica-tions, which engender a high level of health care resourceutilization.19,43 Rates of emergency room visits, hospital

Table 1. Personnel and services recommended for regional ACHDcentres

Type of Service Personnel/Resources

Cardiologist specializing in ACHD One or several 24/7Congenital cardiac surgeon Two or several 24/7Nurse/physician assistant/nurse practitioner One or severalCardiac anaesthesiologist Several 24/7Echocardiography*# Includes TEE, intraoperative TEE

Two or several 24/7

Diagnostic catheterization* Yes, 24/7Noncoronary interventional catheterization* Yes, 24/7Electrophysiology/pacing/ICD implantation* One or severalExercise testing # Echocardiography

# Radionuclide# Cardiopulmonary# Metabolic

Cardiac imaging/radiology* # Cardiac MRI# CT scanning# Nuclear medicine

Multidisciplinary teams # High-risk obstetrics# Pulmonary hypertension# Heart failure/transplant# Genetics# Neurology# Nephrology# Cardiac pathology# Rehabilitation services# Social services# Vocational services# Financial counsellors

Information technology # Database collection# Database support# Quality assessment

review/protocols

24/7, availability 24 hours per day, 7 days per week; ACHD, adultcongenital heart disease; CT, computed tomography; ICD, implantable car-dioverter defibrillator; MRI, magnetic resonance imaging; TEE, trans-esophageal echocardiography.

* These modalities must be supervised/performed and interpreted byphysicians with expertise and training in congenital heart disease.

Reproduced from Warnes et al.25

Ávila et al. S413ACHD: A Growing Epidemic

admissions, and cardiac interventions are several-fold greaterthan in the general population.44-47 Figure 5 depicts commoncauses of hospitalizations.46 Models of health-related costs andoutcomes in adults with congenital heart disease provideeconomic justification for expensive interventions on the basisof striking benefits on quality-adjusted life years.48

Overview of Common IssuesCommon complications that contribute to the growing

epidemic of adults with congenital heart disease include ar-rhythmias, heart failure, pulmonary hypertension, endo-carditis, pregnancy-related issues, and cardiac interventions.

Arrhythmias

Arrhythmias are themost common long-term complication inadults with congenital heart disease, the leading source ofmorbidity and hospital admissions, and a major cause ofmortality.46,49-52All forms of tachy- and bradyarrhythmiasmightbe encountered.53 Figure 6 schematically summarizes factorspredisposing to arrhythmias.54 The prevalence of tachyarrhyth-mias generally correlates with increasing age and complexity ofthe congenital heart lesion (Fig. 7).28,55,56 Sinus node dysfunc-tion is highly prevalent in patients with surgery at or near thesuperior vena cava to the right atrial junction; atrioventricularblock is common in thosewith displaced conduction systems andin the acute postoperative setting.57-60 In 2014, the Pediatric andCongenital Electrophysiology Society together with the HeartRhythm Society proposed recommendations on the recognitionand management of arrhythmias in adults with congenital heartdisease, which were endorsed by the American College of Car-diology, American Heart Association, European Heart RhythmAssociation, Canadian Heart Rhythm Society, and the Interna-tional Society for Adult Congenital Heart Disease.28

Heart failure

Mechanisms for heart failure in adults with congenitalheart disease might involve circulatory overload, ventricular

volume and/or pressure overload, inability of a systemicmorphologic right ventricle or single ventricle circulationto adequately meet metabolic needs, unequal flow distri-butions to lung fields, variable pulmonary vascular integ-rity, and abnormalities of myocardial tissue architecture,electrical conduction, and blood supply.61 As such, man-agement guidelines for acquired heart disease cannot beextrapolated to the complex forms of heart failureencountered in adults with congenital heart disease.Despite the heterogeneity and imprecisions, on the whole,heart failure appears to be increasing in prevalence as thepopulation ages. It is among the most common causes ofhospitalization (see Fig. 5),45,46,52 with some studies sug-gesting that it has surpassed sudden cardiac death as theleading cause of mortality.8,51,62 The incidence of systolicsystemic ventricular dysfunction is highest in those withcyanotic lesions, systemic right ventricles, and uni-ventricular hearts.63 In some forms of congenital heartdisease, diastolic systemic ventricular dysfunction has beencorrelated with arrhythmias and mortality.64 Even in theabsence of overt heart failure as classically defined, somedegree of exercise intolerance is documented in up to one-third.65 When contrasted against quantified exercise ca-pacity, functional symptoms are notoriously underreportedas a result of lifelong adaptation to a chronic disorder.66

Exercise intolerance consistently portends poorer midtermoutcomes, such as hospitalizations and mortality.66

Moreover, in an increasing number of adults withcongenital heart disease and end-stage circulatory failure inwhom cardiac transplantation is not a viable option, end-of-life issues and palliative care assume a prominentrole.67,68

Pulmonary hypertension

Any nonrestrictive communication causing left-to-rightshunting with increased pulmonary blood flow might pro-duce pathological changes to the pulmonary vascular bed,

Figure 4. Time-series analysis: referral to specialized adult congenital heart disease (ACHD) centres and ACHD patient mortality. Observedspecialized ACHD centre referral (black line) and ACHD mortality (grey line) per 1000 ACHD population per year, between 1990 and 2005. Thedashed lines indicate expected trends after the change points identified by Poisson regression, and the black or grey lines represent the observedtrends. Reproduced with permission from Mylotte et al.36

S414 Canadian Journal of CardiologyVolume 30 2014

including vasoconstriction, inflammation, cell proliferation,and vascular remodelling, resulting in increased pulmonaryvascular resistance.69,70 Pulmonary arterial hypertension isprevalent in 4%-10% of adults with congenital heart diseaseand is associated with exercise intolerance and heart fail-ure.69,71 At the extreme end of the spectrum, Eisenmengersyndrome is a multisystemic disorder associated with a 10- to12-fold increase in mortality in those with complex congenitalheart disease.69,72-77 If managed appropriately, many suchpatients survive past the third or fourth decade of life.72 Indeveloped countries, earlier recognition and closure of

intracardiac shunts has resulted in a reduction in the preva-lence of Eisenmenger syndrome.78 Nevertheless, pulmonaryhypertension persists in 3%-13% of patients after septal defectclosure71,79 and implies a worse prognosis.80

Endocarditis

The incidence of endocarditis (approximately 1.1 per 1000patient-years) in adults with congenital heart disease is 20-foldgreater than in the general population,81,82 with a 12%recurrence rate.81,83 Factors associated with endocarditisinclude the type of congenital heart defect, presence of

Figure 6. Factors leading to arrhythmias in (A) before, and (B) after surgery for congenital heart disease. AV, atrioventricular; VT, ventriculartachycardia. Adapted from Escudero et al.54

Figure 5. Most frequent cardiovascular admission diagnoses/symptoms in the CONgenital CORvitia (CONCOR) Dutch national registry populationfrom 2001 to 2005 (n ¼ 5798). All cardiovascular admissions with n ¼ 100 are displayed. Nos, not otherwise specified. Reproduced from Verheugtet al.46

Ávila et al. S415ACHD: A Growing Epidemic

multiple defects, and male sex.81 Systemic embolization, heartfailure, and valvular regurgitation are common complica-tions.84 Surgery is required in up to one-third of patients.84,85

Improvements in antibiotic therapy and earlier surgicalmanagement have resulted in lower rates of complications andmortality over the past decades, with current in-hospitalmortality ranging from 4% to 9%.81,83,84 Educational coun-selling, including hygienic measures and antibiotic prophylaxiswhen indicated, should be incorporated in the care of adultswith congenital heart disease.

Pregnancy

When considered collectively, congenital malformationsare the most prevalent form of heart disease in pregnantwomen86,87 and the leading cardiac cause of maternalmorbidity and mortality in developed countries.25 Pregnancyis the most common noncardiac cause of hospitalization inwomen with congenital heart disease.45,46 Congenital heartdisease carries increased maternal and fetal risks, particularly inthe setting of pulmonary arterial hypertension, subaortic orsubpulmonary ventricular dysfunction, left-sided valvularobstruction, unrepaired aortic coarctation, or aortic rootdilatation in association with other anomalies such as abicuspid aortic valve, Marfan, or Turner syndrome.86-89 Heartfailure and arrhythmias are the most common maternalcomplications, whereas frequent neonatal adverse outcomesinclude small for gestational age birth weight, respiratorydistress, and intraventricular cerebral hemorrhage.90 Womenwith moderate and complex forms of congenital heart disease

should be managed by a multidisciplinary team with appro-priate expertise and delivery should take place in specializedcentres.25-27,91

Congenital cardiac surgeries and interventions

Surgical and catheter procedures are on the increase inadults with congenital heart disease.92 Percutaneous devicesare increasingly used to close septal defects, abnormal vascularconnections, leaks across conduits and baffles, and pseudoa-neurysms; covered stents have enhanced the safety with whichaortic coarctation, conduit stenosis, and branch pulmonarystenosis can be treated; and percutaneous valves have broad-ened the range of therapeutic options in selected patients.93

Cardiovascular surgery is also increasingly performed inadults with congenital heart disease to rectify residual orprogressive lesions in the setting of previous reparative surgery,address previously unoperated disease, palliate nonreparabledefects, and transplant failing hearts.94 Complications aftersurgery occur in 15%-25% of patients and include arrhyth-mias, low cardiac output, stroke, bleeds, and renal failure.Perioperative mortality risk depends on numerous factors butis generally within the 3%-8% range.95-98

ConclusionAdult congenital heart disease is the most rapidly growing

sector of cardiology today, with a patient population that isswiftly increasing in size and complexity. Unique issues,challenges, and considerations are involved in managing adults

Figure 7. Risk estimates for arrhythmias according to type of congenital heart disease. Approximate risk estimates for atrial tachycardia (AT), atrialfibrillation (AF), other supraventricular arrhythmias, ventricular arrhythmia, sinus node dysfunction (SND), atrioventricular (AV) block, and ventriculardyssynchrony are shown across various congenital heart defects (CHDs) of simple, moderate, and severe complexity. D- and L-transposition denotecomplete and congenitally corrected transposition of the great arteries, respectively. The colour-coded pattern ranges from minimal (no shading) tomild (light blue), moderate (medium blue), and high (dark blue) risk. Reproduced Khairy et al.28

S416 Canadian Journal of CardiologyVolume 30 2014

with congenital heart disease, including arrhythmias, heartfailure, pulmonary hypertension, endocarditis, pregnancy,interventions, and surgery. An increasing body of evidencesuggests that outcomes can be improved by referral tospecialized centres with multidisciplinary teams dedicated toclinical care, training, and research in adult congenital heartdisease.

Funding SourcesDr Ávila received a research grant from the Fundación

Alfonso Martín Escudero (Spain). Dr Khairy is supported by aCanada Research Chair in Adult Congenital Heart Diseaseand Electrophysiology.

DisclosuresThe authors have no conflicts of interest to disclose.

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