Double Inlet Ventricle

Seoul National University Hospital

Department of Thoracic & Cardiovascular Surgery

Double Inlet Ventricle

1. Definition A congenital cardiac malformation in which both atria con

nect to only one ventricular chamber by either two separate atrioventricular valves or a common AV valve

Single ventricle, univentricular AV connection

2. History Holmes : Solitary ventricular chamber in 1824 Rokitansky : Double inlet left ventricle in 1875 Taussig : Single ventricle in 1939 Van Praagh : Clear definition of this entity in 1964 Muller & Damman ; PA banding for single ventricle in 1952 Mayo Clinic : Septation on single ventricle

Double Inlet Ventricle

Pathophysiology • A single functional ventricle receives both systemic

and pulmonary venous return via right- & left-sided atrioventricular valves or a single common valve, resulting in mixing of oxygenated & deoxygenated blood and , hence, systemic arterial hypoxemia.

• This defect is also associated with excessive or inadequate pulmonary blood flow, depending on whether there is obstruction to pulmonary flow (e.g., pulmonary stenosis/atresia).

Spectrum of AV Malalignment

Double Inlet VentricleMorphology• Ventricular mass Main( dominant) chamber, Nondominant chamber, Bu

lboventricular foramen• Atria Any types of atrial situs can be present• Atrioventricular connection Usually two AV valves, Valves or common valve overriding in 20 % of cases• Ventriculoarterial connection• Conduction tissue• Coronary arteries

Types of Double Inlet Ventricle

1. Double inlet LV with left-sided rudimentary RV & discordant ventriculoarterial connection {S,L,L}

2. Double inlet LV with right-sided rudimentary RV & concordant ventriculoarterial connection ({S,D,S} : Holme’s heart)

3. Double inlet LV with right-sided rudimentary RV & discordant ventriculoarterial connection {S,D,D}

4. Double inlet and double outlet LV

5. Double inlet and double outlet RV

6. Double inlet RV with concordant ventriculoarterial connection

7. Solitary ventricle of intermediate morphology

Frequent Double Inlet Ventricle

1 DILV with left rudimentary RV & discordant VA connection {S,L,L} * Most frequent type (50%) * Restrictive VSD is frequent : subaortic stenosis, CoA, IAA * Subpulmonic obstruction : favorable clinical course * Frequent stenosis or hypoplasia of AV valve

2 DILV with right rudimentary RV & concordant VA connection {S,D,L} * Less than 10% * Usual atrial arrangement * Frequent right AV valve straddling and overriding * Usually restrictive VSD

3 Double inlet and double outlet right ventricle * About 5% * Usual atrial arrangement, or right isomerism * PS or PA and TAPVR

Double Inlet Left Ventricle (SDD)

Double Inlet Left Ventricle (SLL)

DILV (1)

Morphologic LV

DILV (2)

Morphologic RV

Double Inlet Ventricle

Connections * Atrioventricular concordant discordant : frequent ambiguous * Ventriculoarterial concordant discordant : frequent (60-80%)

Double Inlet Ventricle

Associated cardiac anomalies1 Subaortic stenosis (restrictive BVF or VSD) 2 Pulmonary stenosis (subpulmonary stenosis)3 Pulmonary atresia 4 Patent ductus arteriosus 5 AV valve stenosis, hypoplasia, straddling, overr

iding6 IAA, CoA, aortic arch hypoplasia

Double Inlet Ventricle

Natural History • Incidence 3% of CHD M : F = 2.5 : 1

• Estimated overall survival without treatment 1) Not entirely accurate 2) Less risk of death during neonatal & infant period 3) 57%, 45% remain alive at 1, 5 years 4) Acidosis & low cardiac output is a severe risk factor 5) Systemic outflow obstruction is strong risk factor

Clinical Features & Diagnosis

1. Clinical features are governed by the morphology & associated lesions 2. Variable according to following anomalies

(TAPVR, PS, PA, subaortic obstruction, CoA, IAA,

unobstructed pulmonary blood flow) 3. Pulmonary blood flow 1/3 : decreased 2/3 : increased small % : balanced 4. Electrocardiogram & chest radiography 5. Echocardiography & cineangiography 6. CT angiography & MRA

Systemic Outflow Obstruction

Initial Palliation • Pulmonary artery banding & CoA repair

• Norwood & DKS type operation

• Palliative arterial switch operation

• Alternative surgical approaches ;

PAB, CoA repair, enlargement of BVF,

Apical LV-aortic conduit, Transplantation

Systemic Outflow Obstruction

• Surgical treatment of subaortic stenosis in functional single ventricle

Operative Management

Techniques1 Septation * At any age or in patients with increased PVR, or after palliative procedure * Usually in {S,L,L} type single ventricle * Some of {S,L,D} with arterial switch operation (without PS) * High mortality and complications (complete heart block, residual VSD, A-V valve regurgitation, sudden death)

2 Fontan operation * Usually done around 2 years old * After banding or systemic-pulmonary artery shunt

Fontan Operation

• Right AV valve may be closed as part of Fontan-type repair in double inlet left ventricle

Septation Operation

• Septation is performed through right atrial approach, best illustrated through fishmouth incision in the ventricle

Operative Management

Surgical results1 Septation * Recently improved hospital mortality (10 - 30%)

* Late functional result : good

2 Fontan-type procedure * Nearly same early and late result as other types of CHD

3 Palliative procedure * Pulmonary artery banding

* Systemic-pulmonary shunt

* Atrial septectomy

Suitable Septation Operation

• Apparently, 20-25% of patients with double inlet ventricle are suitable at birth for septation

• Somewhat, not severely, enlarged dominant ventricle• Two reasonable competent and nonstenotic AV valves wi

th little or no overriding or straddling• There should be little or no pulmonary or systemic outflo

w obstruction • Septation should be performed during the first year or t

wo of life• Consideration should be given to a two-stage approach, t

o minimize the probability of producing complete heart block

Indications of Operation

Primary considerations in managing the patients with double inlet ventricle of any type are

(1) their suitability for septation, Fontan operation, or cardiac transplantation and (2) prevention of additional complicating conditions such as subaortic stenosis or pulmonary arterial stenosis

Atrial Isomerism

Atrial Isomerism

Definition• Atrial isomerism is a condition in which the rig

ht-sided and left-sided atria, normally morphologically different, are morphologically similar.

• Atrial isomerism is a subset of situs ambigus, a condition in which usually asymmetric bodily structures tend to be symmetric.

Morphology of Atrial Isomerism

• Bilateral right or left atria• Conduction system• Anomalies of systemic venous connection• Anomalies of pulmonary venous connection• Atrioventricular connection• Atrioventricular septal & other atrial septal defect• Ventricular morphology and VSD• Pulmonary outflow tract• Ventriculoarterial connection• Other coexisting cardiac anomalies

Clinical Features & Diagnosis

• There are no other clinical features specific to atrial isomerism

• Asplenia is associated with an increased number of Howell-Jolly bodies

• Clinical features depend, therefore, on other cardiac anomalies that may present.

• Almost all with right atrial isomerism have sinus rhythm, & complete heart block coexist in 10% of left artrial isomerism, but rare in right atrial isomerism

• Echocardiography• Cardiac catheterization

Natural History

• Determined primarily by details of cardiac structures and nature of coexisting cardiac anomalies.

• However, atrial isomerism itself may contribute to natural history because of its association with neonatal complete heart block and sometimes neonatal death

• Right atrial isomerism is often accompanied by asplenia, a condition believed to render the patient susceptible to infection, particularly pneumococcal.

• Left atrial isomerism is often accompanied by a polysplenia and a high prevalence of extrahepatic biliary atresia

Operative Indications & Technique

Need for surgical treatment is dictated by associated cardiac anomalies, not by atrial isomerism

Technique• Cardiopulmonary bypass• Intracardiac repair• Complex atrial baffle• Fontan type repair• Palliative operations

Complex Atrial Baffle

Results of Surgical Treatment• Overall survival is better with left, compared to right at

rial isomerism • Survival is better when a biventricular repair is undert

aken• Although, overall outcomes of isomerism have been poo

r, results have improved substantially over time• In left atrial isomerism, one third possibly received by

biventricular repair, one third by Fontan, no palliation in others.

• In right atrial isomerism, both short and long-term outcomes are poor, and biventricular repair is possible in few patients.

Incremental Risk Factors for Death

Left atrial isomerism• Lower birth weight• Single ventricle• Gastrointestinal malformation• Biliary atrsia• Congenital AV block• Coarctation of aorta.

Right atrial isomerism• Absence of pulmonary outflow obstruction• Presence of AV valve anomaly• Presence of obstructed pulmonary veins