Single ventricle refers to congenital heart defects where there is only one functional ventricle supporting both the pulmonary and systemic circulations. There are various classifications, and the goal of treatment is to balance blood flow between the lungs and body. Initial medical management uses prostaglandins and aims for balanced pulmonary flow. Later stages involve surgical procedures like shunts, banding of arteries, and ultimately the Fontan procedure to separate circulation to the lungs and body without overloading the single ventricle. Complications can include arrhythmias, heart failure, and protein-losing enteropathy. Long term outcomes are improved with careful patient selection and multi-stage management to optimize hemodynamics at each stage.

2.  Single Ventricle: congenital cardiac malformations that
lack two completely well developed ventricles, and in
which functionally there is only a single ventricular
chamber that supports both pulmonary and systemic
circulations

3.  Classifications of Single ventricle:
 Hearts with common inlet atrioventricular connection [Double-
inlet RV/ Double-inlet LV]
 Hearts with absence of one atrioventricular connection [Tricuspid
atresia / Mitral atresia]
 Hearts with common atrioventricular valve and only one well-
developed ventricle [unbalanced common atrioventricular canal
defect]
 Hearts with only one fully developed ventricle
 Hypoplastic left heart syndrome
 Double-outlet right ventricle and a ventricular septal defect
remote from semilunar valves
 Other rare forms of univentricular hearts

5. 1.Inadequate pulmonary circulation (or ductal dependent)
2.Excessive pulmonary circulation without systemic obstruction
3. Excessive pulmonary circulation with systemic obstruction
4. Balanced pulmonary flow

6.  Medical management: (temporary palliation)
 Prostaglandin E1
 Restoraration of normal acid base status
 Maintain End organ perfusion & function
 Aim of surgical intervention: to improve the natural
history by balancing blood flow between the pulmonary and
systemic circulations and ultimately separating these two
circulations.

7.  In patients with Pulmonary
outflow obstruction:
pulmonary atresia/stenosis
 Consistently SaO2 <75~80%
 Systemic to pulmonary
arterial shunt: modified B-T
shunt: graft from subclavian
A to PA
 To improve SaO2

8.  In patients with excessive pulmonary blood flow:
 SaO2> 85% strongly suggest excessive pulmonary blood flow
 Volume overload to the single ventricle: cause CHF
 Pressure overload to the pulmonary arteriole tree: cause
pulmonary vascular disease
 Tx: PA banding!
 Exclude obstruction of systemic outflow!
 SaO2 80~85%

9.  In patients with excessive pulmonary blood flow with
systemic obstruction-
 DKS procedure (Norwood + BT shunt)

10.  One of the following conditions:
 Mean PA pressure up to 20mmHg
 2 PVR≦ ＜ 4 Wood units but reactive to vasodilators
 Surgically repairable PA hypoplasia or discrete stenosis
present
 McGoon ratio is 2.0 and repairable
 LVED volume is 2SD above the mean[compared with
normal structural heart]
 Target SpO2: 78~85%

11.  Bidirectional cavopulmonary shunt as a staging
Maneuver, usually combined with repair of associated lesion
leading to poor outcome of Fontan’s operation,
including pulmonary arterial stenosis, atrioventricular
valve regurgitation, and systemic outflow tract
obstruction.
 To reduce the volume load on single ventricle & maintain
a viable Spo2.
 So to preserve ventricular function for the subsequent
Fontan

12. COMMENTSCOMMENTS
 End to side connection between the cranial end of SVC & right
pulmonary artery
 Ligation of of azygous
 If b/l SVC, both should be connected to respected Pas
 The cavopulmonary shunt increases effective pulmonary
blood flow without volume-loading the ventricle.
 Systemic venous collateralization may worsen hypoxemia by
reducing the effective pulmonary blood flow
 There are concerns about the growth of the pulmonary
arteries .
 Pulmonary arteriovenous fistulae may be a universal
consequence of the bidirectional cavopulmonary shunt

13. Contd.Contd.
 promotes regression of left ventricular mass in younger
children.
 Improvement in the degree of atrioventricular valve
regurgitation.

14. Intra-atrial baffle /
Lateral tunnel method Extra-cardiac conduit method

15. To drain all systemic veins
directly into PA
Preserve the Functioning single ventricle for
systemic circulation

16.  Goal: BEFORE proceeding to the Fontan circulation,
appropriately regulating pulmonary blood flow since newborn
period
(1) Improve clinical symptoms: cyanosis, CHF
(2) Provide optimal pulmonary artery architecture and low
pulmonary vascular resistance
(3) Preserve systolic and diastolic ventricular function
(4) Preserve atrio-ventricular valve function
(5) Relieve systemic ventricular outflow tract obstruction
(6) Provide anatomic setup for a definitive Fontan repair
 Ideal saturation: SpO2 80%

17. Proper Patient
Sellection!!!!!!

18. Graham and Johns pointed out that theGraham and Johns pointed out that the
following issues or criteria were not includedfollowing issues or criteria were not included
 Diastolic dysfunction,
 Ventricular hypertrophy,
 Systemic outflow tract obstruction,
 Right ventricular type of single ventricle,
 Extensive systemic aortopulmonary collaterals.

19. NECESSARY CRITERIANECESSARY CRITERIA
1. Undistorted pulmonary artery anatomy;
2. Low pulmonary vascular resistance;
3. Low ventricular end diastolic pressure;
4. Absence of obstruction to systemic outflow;
and
5. Preservation of systemic atrioventricular valve
function.

20. METHODMETHOD
 The lateral tunnel technique involves placement of a
baffle along the lateral aspect of the right atrium,
which conveys IVC blood to SVC orifice.
 4 mm fenestration is made in the medial aspect of
baffle to prevent the systemic venous pressure risisng
to intolerable limit.
 Large ASD is created to prevent any restriction of flow
between atria.
 Allows to preserve systemic cardiac output at the
expense of some reduction in arterial saturation.
 Lower operative mortality &p/o pleural effusion.

21. Post operative managementPost operative management
 Minimize PVR
 Monitor systemic & pulmonary pressure & indicators of good cardiac
output as strength of pulse, urine output, BP, CRT.
 Systemic venous hypertension lead to reflex arterial constriction lead
to increased afterload may impair cardiac output- milrinone,
nitroprusside
 Arrhythmias- atrial pacing lowers atrial filling pressure & augments
cardiac output
 Pleural effusion & ascites- complete drainage

22.  Early mortality: 7.7%
 Late mortality:
 Survival 93% at 5years, 91% at 10 years
 Most common causes of death
 Thromboembolism: intra-cardiac thrombus, lack of
Aspirin / Warfarin
 Heart failure: morphological RV, high RA pressure,
protein-losing enteropathy
 Sudden death: cardiac arrhythmias [within fist 5 years
after Fontan surgery]

23.  Complications:
 Early complications: pleural effusion, pericardial
effusion, sternal wound infection, arrhythmia,
stroke……
 Late complications: atrial arrhythmia, ventricular
dysfunction, protein-losing enteropathy,
thromboembolic events

24.  Atrial arrhythmia
 Major risk factor for morbidity and functional
decline after the Fontan procedure
 Incidence: 10~40%
 Most common: Sinus node dysfunction!! [sinus
node injury while REDO or disturbance of its
blood supply]
 Cause: RA dilation, RA incision
 Tx: anti-coagulant if refractory

25.  Protein-losing enteropathy
 Very poor prognosis!!! : 5-yr survival 59%, 10-yr
survival <20%
 Incidence: 3.8%~10%
 Lymphatic drainage dysfunction
 Tx: anticongestive therapy, steroid, heparin, atrial
fenestration, heart transplantation!

26.  Ventricular dysfunction/heart dailure: 8.3%
 Preload reduced to 50~70% of normal for BSA
 Ventricle: from volume overload and overstretched
to severely undeloaded
→”Disuse hypofunction”: remodelling, reduced
compliance, poor ventricular filling, continuous
declining cardiac output
 Tx: heart transplantation! [Late take down or
fenestration before heart transplantation]

27.  Right atriomegaly and hepatic dysfunction
 Dilatation of the coronary sinus
 Pulmonary arteriovenous malformations
 Myocardial dysfunction and failure
 Ventricular outflow obstruction
 Obstruction of pulmonary veins
 Recanalization of ligated main pulmonary trunk
 Systemic venous collateralisation
 Bronchitis
 Pancreatitis
 WPW syndrome