Univentricular heartDouble inlet left ventricle

• DILV is the commonest form of “single or univentricular heart”

• In DILV , the ventricle is unseptated, septation of the ventricle has disappointing early and late results.

• Fontan operation dramatically altered the outcomes for many pts with single ventricle malformation.

• The important management strategies is to protect the integrity of the myocardium and pulmonary vascular beds so that these patients will meet the criteria for Fontan operation

Fundamental strategies to prepare for a Good Fontan

• 1)Preserved systolic and diastolic function of myocardium• 2)Prevent dysproportional myocardial hypertrophy and poor

ventricular compliance• 3)Maintain functional integrity of atrioventricular valve• 4)Protect pulm vascular bed from hypertensive changes

Prevalence of DILV 1.25% to 1.375% of all congenital ht diseaseThere are 3 morphological types of single ventrilcle;1)Left ventricle type with/without rudimentary right ventricle2)Right ventricle type with/without rudimentary left ventricle3)Indeterminate or undifferentiated type

• Univentricular atrioventricular connection of left ventricular type is found in 60n -70% of pts with single ventricle, single right ventricle is 5-25%,indeterminate is <5%

Changing in form and function of hearts with one dominant ventricle

These phenomena are applicable to hts with1)Double inlet or absent right atrioventricular Connection2)Absent left atrioventricular connnection

These changing phenomenon include

• 1)Progressive systemic outflow tract obstruction• 2)Progressive change in ventricular function/hypertrophy• 3)Progressive atrioventricular valve regurgitation• 4)Progressive left atrial hypertension• 5)Progressive pulmonary outflow tract obstruction• 6)Progressive deterioration in atrioventricular conduction• 7)Development of Pulm vascular obstruction• 8)Development of aortopulm collaterals blood flow

Progressive systemic outflow tract obstruction

• May present at birth or acquired• .• The most frequent setting for subaortic stenosis is:• i)A univentricular atrioventricular connection of LV type• Ii)Rudimentary RV and TGA• The aorta originates above the rudimentary RV and bld

reaches the aorta and systemic circulation through the bulboventricular foramen

• DILV, TGA, rudimentary RV, the VSD tends to be larger and not potentially restrictive when there is naturally occurring RVOTO

• ConverselyIn the absence of naturally occurring RVOTO, VSD tend to be

smaller than aortic root diameter , substrate for LVOTO

Acquired LVOT after PA banding, explanation:1)VSD/ bulboventricualr foramen was initially smaller than aortic

root , thus predisposed to spontaneous diminution in size2)PA banding promoted myocardial hypertrophy, this likely

contributed to further reduction in size of VSD with reduction of Pulm blood flow.

The median duration from banding to recognition of subaortic stenosis was 2.3 yrs

• reduction of Pulm blood flow• + • myocardial hypertrophy secondary to PA banding• +• Increased ventricular afterload• +• Natural predisposition for spontaneous diminution

Systemic outflow tract obstruction

Progressive change in ventricular hypertrophy

• Ventricular hypertrophy is risk factor for poor outcome after Fontan operation related to impaired diastolic function.

• LVOTO causes ventricular hypertrophy, thus the earlier the LVOTO is resolved, the outcome of Fontan is better, preferably in the neonatal period.

• Surgical procedures employed to treat subaortic stenosis are many, but the only procedure that proved useful is

• 1)Damus Kay stansel operation plus systemic to pulm shunt in neonate or young infant

• 2)Damus Kay Stansel operation plus Cavopulm shunt

• Long term PA banding of the pulm trunk especially when the band is close to the pul valve can lead to morphological changes in the pulm valve and pulm regurgitation.

• There are clinical observations indicating that neonatal pulm artery banding with subsequent conversion to Damus Kay stensel with Cavopulm shunt or Fontan does not importantly compromise the function of the pulm valve.

Progressive atrioventricular valve regurgitation

• Occurrence is not ventricular specific, but more common in pts with single right ventricle and a common atrioventricular valve, more

• Frequent in pts with right isomerism.• Natural history Toronto series• Double inlet atrioventricular connection, RV dominant, 46%

noted to have abnormal AV valve function at initial presentation.• 37% dying in neonatal period

• It is unlikely that severe AVVR would improved solely by construction of Cavopulm shunt

Progressive left atrial hypertension

• Left atrial hypertension is common in pts with absent, imperforate or severely obstructed left AVV connection and a restrictive interatrial communication

• In the situation when there is naturally occurring pulmonary stenosis, left atrial hypertension may compromise the function of a surgically created Systemic to pulm artery shunt

• Severe pulm venous hypertension impacts on the pulm vascular bed, it is advantageous to relief the obstruction and allow remodelling before the construction of the cavopulm shunt or Fontan operation, impedance to pulm flow in the Fontan circulation is very unforgiving

• Sequential assessment of the atrial septum is important in pts with stenosis or atresia to the systemic AVV

Progressive pulm outflow obstruction

• Any heart malformation with a dominant left ventricle, rudimentary right ventricle and concordant ventriculoarterial connections, there is potential for pulm outflow tract obstruction.

• The development of pulm outflow obsturction depends on the initial size of VSD, nature of pulm valve and infundibulum

and anatomic obstruction of the branch PAS Progressive cyanosis and hypoxaemia may not be related to progressive pulm

outflow tract obstruction alone , it may be due to confounding left atrial hypertension.

It is important both to maximise mixing at atrial level to obviate disadvantageous streaming and to avoid left atrial hypertension, the interatrial communication must be wide open

Progressive deterioration in atrioventricular conduction

• Very little information on the incidence of spontaneous CHB.

• The incidence is less common compared to pts with double discordance

Development of pulm vascular obstruction

• Pts with unprotected pulm blood flow and obstructive anomly of the aortic arch die in infancy

• Adult s univentricular heart and eisenmenger syndrome, mean age of death was about 28 yrs old. 5 year survival after the initial visit was 34%

Development of aortopulm collaterals

• Vascular endothelial growth factor and basic fibroblast growth factor are increased in children with cyanotic heart disease

Outcome analysis

• Prospective Bohemian Survival study in DILV• 1ST WEEK of life :77.6%• 6 months : 41.8%• 1st year : 38.8%• 10 yrs to 15 yrs: 35.6%

Franklin et al Great Ormond Street hospital for Sick Children

• 1)DILV, TGA, BALANCED OR LOW PULM BLD FLOW• 1 YR survival: 96% /90%• 10 yr survival: 91% /79%

• 2)DILV, TGA, HIGH and UNOBSTRUCTED PULM BLD FLOW• 1YR survival: 79%• 10 YR survival : 60%

• 3)DILV, UNOBSTRUCTED PULM BLD FLOW , LVOTO• 1YR survival: 36%• 10 YR survival: 11%

• 4)R isomerism, Double inlet and double outlet RV, A common AVV Reduced pulm bld flow and extracardiac pulm venous connection

• 1yr survival:3%• 10yr survival: 0%

In the same paper, they also assess the outcome and potential for later Fontan

• At presentation 71% pts potential for Fontan operation , however by 2 yrs of age only 57% were alive and suitable for Fontan.

Survival after definitive palliation

• Modified stage-one Norwood , mortality 10%• 2nd stage: 2.5%• Modified Fontan:4%

• Ventricular septation: numbers are small, initial experience of Kurosawa: 1967 to 1983: mortality 36%

• In pts considered ideal morphology for ventricular septation and without need for AVV replacement , late survival was 77%