Download Introduction to cardiac conditions

Introduction to cardiac conditions
PICU cardiac course 2014
Objectives:
At the end of this session I will be able to…
• Describe the normal heart structure
• Describe common cardiac conditions
including;
• Signs and symptoms
• Management and treatment
• Discuss different cardiac shunts
Normal Heart Anatomy
Cardiac pressures and Sa02
Cardiac Terminology
• Cardiac output- CO=HR x SV
(Heart rate- no of heart beats per minute) x (Stroke
volume- the amount of blood expelled by the left
ventricle with each contraction)
• Preload- The stretch on the heart before it contracts
• Afterload- It refers to the resistance against which
the ventricles must work against to eject their blood
volume
• Contractility- Refers to the strength and efficiency of
a contraction.
8–10 in 1000 births have
some kind of congenital
heart abnormality
Classification of Congenital
Heart Disease
Congenital
Cardiac
Disease
Acyanotic
Increased
pulmonary
blood flow
75%
Obstruction of
flow from
ventricles
Cyanotic
Decreased
pulmonary
blood flow
Source: http://www.racgp.org.au/gplearninglinks/ccheartdefects_may2000.htm
25%
Mixed blood
flow
Lesions with increased blood
flow (Acyanotic)
• ASD
• VSD
• AVSD
• PDA
Obstruction to blood flow from
ventricles (Acyanotic)
• Coarctation of the aorta
• Aortic stenosis
• Pulmonary stenosis
Decrease pulmonary blood
flow (Cyanotic)
• Tetralogy of fallot
• Tricuspid atresia
Mixed blood flow (Cyanotic)
•
•
•
•
TGA
TAPVD
Truncus arteriosus
Hypoplastic left heart syndrome
Atrial Septal Defect
• An Acyanotic increased pulmonary
blood flow lesion.
• Opening between the atria.
* 5-10% of
congenital heart
disease
Source: www.rch.org.au
Signs & Symptoms
• Left to right shunting
• Most patients asymptomatic
• Present 3 to 6 weeks with soft murmur and
can have a large heart on x-ray.
• Present with poor feeding,
lower respiratory tract
infection and small amount
of heart failure.
• Cyanosis infrequent.
Treatment
• Spontaneous closure likely of small
secundum type ASD’s.
• Device closure.
• Surgical correction either by
pericardium patch or sutures.
Source: www.rch.org.au
Ventricular Septal Defect
• An Acyanotic lesion with increased
pulmonary blood flow.
• Opening between the right and left
ventricle.
* 30% of congenital
heart disease
Source: www.rch.org.au
Signs & Symptoms
• Majority of undiagnosed presentations occur
at 6-8 weeks of age as the Pulmonary
Vascular Resistance falls.
• Left to right shunting
• Small shunt causes patient to be
asymptomatic
• A large shunt will increase pulmonary blood
flow, leading to tachycardia, increased
respiratory rate, sweating, poor feeding and
poor weight gain.
Eisenmenger’s Complex
• Increasing Pulmonary Vascular
Resistance to protect overflow of blood.
• Causes changes to vasculatureirreversible.
• PVR>SVR= shunt reversal= cyanosis
Treatment
• Medical Therapy i.e.. Lasix, Aldactone
• Surgical Repair with a
device.
Source: www.google.com
Patent Ductus Arteriosus
• A cyanotic heart disease with increased
pulmonary blood flow
• Persistent opening between the main pulmonary
artery and aorta.
• Closure begins
10-15mins after birth.
• Complete closure
3 weeks post birth.
Source: Pedheart
5-12% of congenital heart
disease
Signs & Symptoms
• Left to right shunt controlled by diameter of
PDA.
• Small PDA – Resistance to flow high
across ductus.
• Large PDA – CHF, poor feeding,
increased respiratory
rate and slow weight
gain.
Failure of the PDA to close
• Closure depends on:
• 1) increased oxygenation with first breaths=
constriction of the ductal tissue
• 2) Reduction in naturally occurring prostaglandin=
contraction of the muscular ductal tissue.
• Delayed closure due to; prematurity,
mechanical ventilation and diuretics, reduced
partial pressure of oxygen, maternal infection
Treatment
• Medical Management
– Use of diuretics and fluid restrictions.
• Cardiac Catheter
– Coils or balloons used to ligate PDA
via cardiac catheter.
• Surgical Management
- Ligation via thoracotomy with no bypass.
Tetralogy of Fallot
• A cyanotic lesion with decreased blood flow.
• 2 types of TOF - Pink TOF
- Cyanotic TOF
• Made of 4 components:
1. Stenosis of Pulmonary
Artery
2. Ventricle Septal Defect
3. Right sided aorta.
4. Hypertrophic right ventricle.
Source: Pedheart.org.au
Signs & Symptoms
• Right to left shunting
• Hypoxic Spells or ‘TOF Spells’
- Induced by crying, cyanosis,
increased respiratory rate.
- Decreased pulmonary blood flow
caused by infundibula muscle spasm.
- Prolonged hypoxia = Loss of
consciousness, brain damage.
Treatment
• Hypoxic Spells – Squatting increases systemic
vascular resistance
-Morphine, volume
- Oxygen and mechanical
ventilation.
• TOF – Surgery – BT Shunt
- TOF Repair
Source: www.rch.org.au
Coarctation of the Aorta
•
• Acyanotic heart lesion
with obstruction to flow
from left ventricle.
• Discrete Narrowing of the
aortic arch.
Source: www.rch.org.au
6-12% of Congenital heart disease
Signs & Symptoms
• Right to left flow across
PDA to descending aorta.
• Higher BP’s in arms than
legs.
• Degree of cyanosis
depending on degree of
narrowing of coarctation.
• Severe coarctation will
show signs of decreased
ventricular function,
heart failure, poor feeding
etc.
Pre and Post Duct presentation
Treatment
• Prostin at birth to reopen/ maintain PDA
• Catheter – Dilation of aorta
with balloon.
• Surgical Repair –
Aorta dissected and
end-to-end/ end to side
anastomosis
Source: www.rch.org.au
Transposition of the Great Arteries
• A cyanotic heart lesion
with mixed blood flow.
• Aorta and Pulmonary
artery positioned across
ventricle from original
position.
• On average greater than
normal birth weight
Source: Pedheart
4-5% of congenital cardiac disease
Treatment
• At birth – Prostin to
maintain PDA
• Balloon Atrial
Septostomy, if no
VSD
• Switch Repairusually Day 7-10
Source: www.rch.org.au
Hypoplastic Left Heart Syndrome
• A cyanotic heart lesion
with mixed blood flow.
• Hypoplastic left atrium,
left ventricle and aorta
arch.
• 25% chance of death in
first week of life.
• No Systemic flow unless
PDA or intra atrial
communication is
present.
Source: rch.org.au and Pedheart
Signs and Symptoms
• Right to left shunting across PDA to allow
systemic blood flow.
• Falls in pulmonary vascular resistance sees
blood diverts to lungs rather than systemic
system i.e. SaO2 97-100%
• Rise in pulmonary vascular resistance sees
greater systemic blood flow at a price of hypoxia.
• Increased systemic resistance drops systemic
output leading to shock.
• Pulmonary congestion can occur if atrial
communications are small.
• Cyanosis present even with PDA.
1-2% of all congenital heart
defects
Treatment
• Medical – Prostin used
prior to surgery to
maintain PDA.
• Surgical:
Norwood – Day 2.
- Main pulmonary artery
divided to construct
aorta.
- PDA ligated, BT shunt
inserted and ASD
maintained.
BCPS – aprox 4months
Fontan – aprox 4-5yrs
Types of Shunts
Blalock-Taussig shunt (BT Shunt) (Classic and Modified)
Bidirectional cavopulmonary shunt (BCPS)
Central shunt
Fontan
Blalock-Taussig Shunt
Source: http://images.google.com.au
“as an utterly miserable, small six-year old
boy who was no longer able to walk." His
skin was intensely blue, his lips deep
purple. Just after the final stitches were
tied and the clamps released, the
anesthesiologist called out, "The boy's a
lovely color now!" Dr. Taussig remembered
the thrill of walking around to the head of
the operating table to see those "lovely
normal pink lips." She reported that after
his recovery from the operation he was a
happy, active child.
http://www.medicalarchives.jhmi.edu/firstor.htm
Modified Blalock-Taussig Shunt
• Gortex tube sewn
between aorta and
pulmonary artery
• Palliative shunt
• Steals from systemic
blood flow to increase
pulmonary blood flow
Central Shunt
• Graft between
ascending aorta and
main pulmonary
artery
• High pressures
• Graft size determines
the size of the shunt
Bidirectional Cavopulmonary
Shunt (BCPS)
• SVC separated at the join
to right atrium
• SVC anastomose to right
pulmonary artery
• Increases pulmonary
blood flow
• Decrease volume of blood
returning to heart
• Improved arterial
oxygenation
• First stage of Fontan
Source: www.rch.org.au
Aims of BT and BCPS/Glenn
•
•
•
•
•
Palliative measure
Growth of Pulmonary arteries
Lead up to fontan
Reduces cardiac workload/CCF
Provides adequate pulmonary flow and
better systemic oxygen delivery
Fontan
The Fontan
• 3rd stage can be performed from 2-16
years of age
• Systemic blood flow is redirected from
both IVC and SVC directly to pulmonary
arteries
• Optimises cardiac output
• Intracardiac and Extracardiac
Intracardiac
• A tunnel-like patch is placed inside the
atrium so that blood returning from the
IVC is directed through this tunnel
• Atrial Septum removed
• Less common
Extracardiac Fontan
• The IVC is sewn directly onto a conduit,
and the underside of the pulmonary artery
• Routing the blood flow outside of the heart
• The atrial septum is
removed if not done
already
• Less complicated
• Less incidence of
effusions and
arrhythmias
Fenestrations
In either method, a hole or “fenestration”
is often made between the Fontan circuit
and the right atrium
Circulation Journal (Circulation. 2007;116(suppl 1):1-157-1-164)
Who qualifies for a Fontan
• Generally children with single ventricle
lesions
• Tricuspid Atresia
• HLHS
• Pulmonary Atresia Double Inlet Left
Ventricle
• Double outlet Right Ventricle (with other
defects)
• Ebstein's Anomaly
Outcomes
•
•
•
•
Post fontan- Sa02 90’s
<4 mortality rates 20%
4-16yo mortality rates 7-8%
Limitations
• Experience can vary greatly on how active
they were prior to surgery
• Still Palliative!!
http://www.fontanregistry.com/
Questions??