A ppt on Hypoplastic left heart syndrome covering all important concepts. Useful for MD/DCH/DNB Pediatrics exams

1. Hypoplastic Left Heart
Syndrome
Dr.Himanshu S Dave

2. Pathophysiology
• The term hypoplastic left heart is used to
describe a related group of anomalies that
include various degrees of underdevelopment
of the left side of the heart: stenosis or atresia
of the aortic and mitral valves, and hypoplasia
of the left ventricular cavity and ascending
aorta.

3. • Two broad categories include aortic atresia
with hypoplastic but perforate mitral valve or
with mitral atresia.
• The left ventricle may be only moderately
hypoplastic, very small and nonfunctional, or
totally atretic.

4. • In the immediate neonatal period the right
ventricle maintains both the pulmonary
circulation and the systemic circulation via the
ductus arteriosus.
• Pulmonary venous blood passes through an
ASD or dilated foramen ovale from the left to
the right side of the heart, where it mixes with
systemic venous blood (total mixing lesion).

5. • When the ventricular septum is intact,all the
right ventricular blood is ejected into the main
pulmonary artery; the descending aorta is
supplied via the ductus arteriosus, and flow
from the ductus also fills the ascending aorta
and coronary arteries in a retrograde fashion.

6. • The major hemodynamic abnormalities are
inadequate maintenance of the systemic
circulation and, depending on the size of the
atrial-level communication, either pulmonary
venous hypertension (restrictive foramen
ovale) or pulmonary overcirculation
(moderate or large ASD).

7. Clinical Manifestations
• Although cyanosis may not always be obvious
in the 1st 48 hr of life.
• A grayish blue skin color is soon apparent and
denotes a mix of cyanosis and poor perfusion.
• The condition is diagnosed in most infants in
the 1st few hr or days of life.

8. • Once the ductus arteriosus begins to close,
signs of poor systemic perfusion and shock
predominate.
• All the peripheral pulses may be weak or
absent.
• A palpable right ventricular parasternal lift
may be present along with a nondescript
systolic murmur.

9. • This lesion may be isolated or associated in 5–
15% of patients with known genetic syndromes,
such as Turner syndrome, trisomy 13, 18, or 21,
Jacobsen syndrome (11q deletion), Holt-Oram
syndrome, and Rubinstein-Taybi syndrome.
• In these circumstances, noncardiac
manifestations of the syndrome may be evident
and influence the clinical outcomes.
• Occasionally it is familial and inherited as an
autosomal recessive trait.

10. Diagnosis
• On chest radiograph, the heart is variable in
size in the 1st days of life, but cardiomegaly
develops rapidly and is associated with
increased pulmonary vascularity.

11. • The initial ECG may show only the normal
neonatal pattern of right ventricular
dominance, but later, P waves become
prominent and right ventricular hypertrophy is
usual with reduced left ventricular forces.

12. • The echocardiogram is diagnostic and
demonstrates absence or hypoplasia of the
mitral valve and aortic root, a variably small
left atrium and left ventricle, and a large right
atrium and right ventricle.
• Doppler echocardiography demonstrates
whether the mitral and aortic valves are
severely stenotic or totally atretic.

13. • The diagnosis of hypoplastic left heart
syndrome (HLHS) can usually be made without
need for cardiac catheterization.
• If catheterization is necessary, the hypoplastic
ascending aorta is demonstrated by
angiography.

14. Prognosis and Complications
• Untreated patients most often succumb
during the 1st few mo of life, usually during
the 1st or 2nd wk.
• Up to 30% of infants with HLHS have evidence
of either a major or a minor central nervous
system abnormality.
• Other dysmorphic features may be found in
up to 40% of patients.

15. Treatment
• Surgical therapy for HLHS is associated with
improving survival rates, reported as high as 90–
95% for the 1st-stage palliation in experienced
centers.
• The 1ststage repair is designed to construct a
reliable source of systemic blood flow arising
from the single right ventricle using a
combination of aortic and pulmonary arterial
tissue, and to limit pulmonary blood flow to avoid
heart failure and prevent the development of
pulmonary vascular disease.

16. • The surgical procedure typically used is the
Norwood procedure or the Sano procedure.
• If a Norwood or Sano procedure is to be
performed, preoperative medical
management includes correction of acidosis
and hypoglycemia, maintenance of ductus
arteriosus patency with PGE1 (0.01-0.20
μg/kg/min) to support systemic blood flow,
and prevention of hypothermia.

17. • Preoperative management should avoid
excessive pulmonary blood flow; either
through management of ventilator settings,
increasing the concentration of inspired CO2
or decreasing the concentration of inspired
O2.
• Balloon dilation of the atrial septum (if
restrictive) may be indicated.

18. • The Norwood or Sano procedure is usually
performed in 3 stages

19. • Stage I includes an atrial septectomy and
transection and ligation of the distal main
pulmonary artery; the proximal pulmonary artery
is then connected to the transversely opened
hypoplastic aortic arch to form a “neoaorta,”.
• A synthetic aortopulmonary (Blalock-Taussig)
shunt connects the aorta to the main pulmonary
artery to provide controlled pulmonary blood
flow.

20. • In the Sano modification, a right ventricle–to–
pulmonary artery conduit is used instead of an
aortopulmonary shunt to provide pulmonary
blood flow, temporarily creating a double-
outlet right ventricle.
• The operative risk for these 1st-stage
procedures has improved dramatically in the
past 2 decades, and the best reported results
demonstrate a 90–95% survival rate.

21. • Stage II consists of a Glenn shunt
anastomosis to connect the superior vena
cava to the pulmonary arteries at 2-6 mo of
age.
• Stage III , usually performed at 2-3 yr, consists
of a modified Fontan procedure
(cavopulmonary isolation) to connect the
inferior vena cava to the pulmonary arteries
via either an intraatrial or external baffle.

22. • Another alternative therapy is cardiac
transplantation , either in the immediate
neonatal period, thereby obviating stage I of
the Norwood procedure, or after a successful
stage I Norwood procedure is performed as a
bridge to transplantation