congenital heart diseases of burao university.pptx

Congenital heart
diseases
pathology
Instructor: Dr Hamza Gaydh
Names:
1. Abdiaziz Essa Adam
2. Barwako Abdirahman
3. Fardus Mohamed Mohamuod
4. Asma jama
5. Hamse Mohamed
6. Fadumo ahmed

Topics :
Malformations associated the left to right shunts.
arterial septal defact
ventricular septal defact
patent ductus arteriosus
Malformation associated the right to left shunts.
Malformation associated with obstructive lesions.
aortic coarctations
pulmonary valve stenosis
aortic valve stenosis

Introduction
Both genetic and environmental factors contribute to congenital abnormalities of the
heart or great vessels, which account for 20% to 30% of all birth defects.
Congenital heart disease affects nearly 1% of births (roughly 40,000 infants per year),
Pathogenesis usually occurs due to faulty embryogenesis during Gestational weeks
specially between week 3-8 when cardiovascular system is developing. The cause is
unknown 90% of the cases but the known etiological causes are;
Congenital rubella infections
Teratogen exposure
Maternal diabetes and genetic factors

Structural defects are categorized :
Defects cause ;
• Malformations associated the left to right shunts.
• Malformation associated the right to left shunts
• Malformation associated with obstructive lesions.

Malformations associated the left to right shunts :
• Disorders associated with Left-to-right shunts are the most common types of
congenital cardiac malformations. They include atrial septal defects (ASDs),
ventricular septal
• defects (VSDs), and patent ductus arteriosus (PDA). ASDs typically increase
only right ventricular and pulmonary outflow volumes, while VSDs and PDAs
cause both increased pulmonary blood flow and pressure.

Cont..:
 At first, cyanosis (bluish skin from low oxygen) is not present in these defects.
But if the left-to-right shunt continues for a long time, it can lead to pulmonary
hypertension. When this happens, the blood flow can reverse (right-to-left),
sending unoxygenated blood into the body’s circulation. This stage is marked by
the appearance of cyanosis and is known as Eisenmenger syndrome.
 Once severe pulmonary hypertension has developed, the heart defect becomes
irreversible. That is why early treatment—usually surgical correction—is
recommended before these complications occur.

Atrial Septal Defect
• During normal heart development in the fetus, there are temporary
openings (called ostium primum and ostium secundum) between the
right and left atria. These openings later form the foramen ovale. This
connection is important because it lets oxygen-rich blood from the
mother pass directly from the right atrium to the left atrium, which
helps support fetal growth.
• Later in pregnancy, thin tissue walls (septum primum and septum
secundum) grow to cover and close the foramen ovale. After birth,
when blood pressure in the left atrium becomes higher than in the right
atrium, the septa usually fuse permanently in about 80% of people.

Cont..
• In the other 20%, the foramen ovale stays slightly open (patent foramen
ovale, PFO). The flap is usually large enough to cover the hole, but
sometimes pressure changes—like when sneezing or straining during a
bowel movement—can cause blood to pass from the right to the left
atrium. This usually causes no problems, but in rare cases, it can allow a
paradoxical embolism, where a blood clot from the veins (such as from
the legs) travels through the PFO and enters the arteries of the body.
• Unlike a PFO, an atrial septal defect (ASD) is a true abnormal hole in the
atrial septum that allows free blood flow between the two atria. Most
ASDs (about 90%) are ostium secundum defects, where the septum
secundum does not grow enough to close the second opening.

Cont..
• Atrial septal defects (ASDs) are among the most common heart defects first discovered in
adults. At first, they cause a left-to-right shunt because pressure in the lungs and right side of
the heart is lower than on the left side. Most ASDs are well tolerated, especially if the
opening is less than 1 cm. Even larger ASDs often cause no symptoms in childhood.
• However, over time, the constant extra blood flow can lead to volume and pressure
overload, which may result in pulmonary hypertension. For this reason, ASDs are usually
closed by surgery or catheter-based procedures to prevent serious problems later, such as:
• Heart failure
• Paradoxical embolism (clots crossing to the systemic circulation)
• Permanent damage to lung blood vessels

Cont..
• The risk of death from the procedure is very low, and long-term survival after
closure is about the same as in people without ASDs.

Ventricular Septal Defects
• Ventricular septal defects (VSDs) are the most common type of congenital heart
defect present at birth. They cause a left-to-right shunt, meaning blood flows
from the left ventricle to the right ventricle.
The ventricular septum normally develops from two parts:
• A muscular ridge that grows upward from the apex of the heart.
• A thin membranous wall that grows downward from the endocardial cushions.

Cont..
• These two structures fuse to form a complete septum. The membranous (upper
basal) part is the last to form, and this area is where about 90% of VSDs occur.
• Most VSDs close on their own during childhood. However, only about 20–30% of
cases are isolated VSDs (occurring alone). The rest are linked with other heart
malformations.

patent ductus arteriosus
• Ductus arteriosus is a connecting link between pulmonary trunk and Aorta that
normally closes at birth.
• It arises from the pulmonary artery and joins the aorta just distal to the origin of
the left subclavian artery.
• During intrauterine life, it permits blood flow from the pulmonary artery to aorta,
by bypassing the blood from the un-working or underdeveloped lung. Within
1 to 2 days of birth the ductus normally constrict and closes in response to
increase arterial oxygenation and decrease pulmonary vascular resistance
and the declining levels of prostaglandin E2 derived from the placenta

Cont..
• Known cause of persistent patent ductus arteriosus include hypoxia and certain
autosomal dominant gene defect, but 90% of cases are uncertain pathogenesis.
• Small ductal shunt generally causes no symptoms but larger defect eventually lead
to shunt reversal, cyanosis and heart failure

Right-to-Left Shunts (Cyanotic Congenital Heart
Diseases)
• Right-to-left shunts occur when poorly oxygenated blood from the
right side of the heart enters systemic circulation without passing
through the lungs for oxygenation.
• This leads to early cyanosis (“blue babies”).
• Most are not pure shunts but involve a combination of a structural
shunt + an obstruction.
1. Tetralogy of Fallot
• Pulmonary stenosis
• Right ventricular hypertrophy
• VSD (ventricular septal defect)
• Overriding aorta

Major causes
1. Tetralogy of Fallot
• Pulmonary stenosis
• Right ventricular hypertrophy
• VSD (ventricular septal defect)
• Overriding aorta
Blood flows from RV LV through VSD due to obstruction of RV outflow.
→
2. Transposition of the Great Arteries (TGA)
• Aorta from RV, pulmonary artery from LV.
• Systemic and pulmonary circulations run in parallel.
• Requires another shunt (PDA, VSD, or ASD) for survival

3. Tricuspid Atresia
• No tricuspid valve RV absent or small.
→
• Needs ASD + VSD or PDA for blood flow.
4. Total Anomalous Pulmonary Venous Connection (TAPVC)
• Pulmonary veins drain into systemic veins RA instead of LA.
→
• Requires ASD or PFO for oxygenated blood to reach LV.
5. Persistent Truncus Arteriosus
• Single arterial trunk from both ventricles mixed blood to body &
→
lungs.
• Always has VSD.
Cont..

Right-to-Left Shunts: Mechanism
• Why a Right-to-Left Shunt Occurs
• When blood from the right atrium (RA) cannot enter the right ventricle (RV) due to
an obstruction, it must find an alternative route to circulate.
• The only available path is through a defect in the atrial septum into the left atrium
(LA).
• This creates a right-to-left shunt at the atrial level, where blood flows directly from
RA → LA.

How this bypass the lungs
• Normally, blood from the RA goes to the lungs to get oxygenated. In a right-
to-left shunt:
• Deoxygenated systemic venous blood bypasses the lungs.
• It mixes with oxygenated blood from the pulmonary veins in the LA.
• The result is mixed or poorly oxygenated blood being pumped to the
systemic circulation, leading to cyanosis (bluish discoloration of skin and
mucous membranes).

Clinical significance
• Early cyanosis is a hallmark of cyanotic congenital heart diseases.
• Understanding this mechanism helps guide diagnosis and surgical
planning for affected patients.

Malformation associated with obstruction.
Congenital obstruction to blood flow may result from obstruction in the aorta due
to narrowing (coarctation of aorta), obstruction to outflow from the left ventricle
(aortic stenosis and atresia), and obstruction to outflow from the right ventricle
(pulmonary stenosis and atresia).

AORTIC STENOSIS AND ATRESIA.
• The most common congenital anomaly of the aorta is bicuspid aortic valve
which does not have much functional significance but predisposes it to
calcification. Congenital aortic atresia is complete absence or failure of
formation of the aortic valve opening, rare and incompatible with survival. Aortic
stenosis may be acquired (e.g. in rheumatic heart disease, calcific aortic stenosis)
or congenital.
• Calcific aortic stenosis is Progressive narrowing of the aortic valve due to
calcific deposits on the cusps that prevent full opening.

Pathogenesis
Progressive calcification of the aortic valve leaflets occurs without
prior rheumatic damage.
• Calcium deposits form at the bases of the cusps (near the aortic
outflow side) → cusps become rigid → narrowed valve orifice
• Clinical consequence:
• Causes left ventricular pressure overload → concentric LV
hypertrophy → angina, syncope, and possible sudden death.

Cont..
Congenitally bicuspid aortic valve calcification – presents earlier (40–60
years).
MORPHOLOGIC FEATURES.
• Congenital aortic stenosis may be of three types: valvular, sub-valvular and
supravalvular.
1. Valvular stenosis: location At the level of the valve leaflets. Result in
Thickened, calcified, and immobile cusps → reduced orifice area.
2. sub-valvular stenosis (subaortic stenosis)
Location: Below the valve, in the left ventricular outflow tract (LVOT).
The major Cause is Hypertrophic cardiomyopathy (HC

Cont..
3. Supravalvular stenosis
Location: Above the valve, in the ascending aorta
Causes Williams-Beuren syndrome is deletion of chromosome and lead
to reduce elastin content

PULMONARY STENOSIS AND ATRESIA.
• Isolated pulmonary stenosis and atresia do not cause cyanosis and hence are
included under acyanotic heart diseases.
• MORPHOLOGIC FEATURES.
• Pulmonary stenosis: It is the commonest form of obstructive congenital heart
disease comprising about 7% of all congenital heart diseases. It may occur as a
component of tetralogy of Fallot or as an isolated defect.
• Pulmonary stenosis is caused by fusion of cusps of the pulmonary valve forming
a diaphragm-like obstruction to the outflow of blood from the right ventricle
and dilatation of the pulmonary trunk.

Cont..
• Pulmonary atresia: There is no communication between the right ventricle and
lungs so that the blood bypasses the right ventricle through an interatrial septal
defect. It then enters the lungs via patent ductus arteriosus

Aortic Coarctation
• The aorta is the big blood vessel that carries blood from the heart to the whole
body. In this disease, one part of the aorta is narrow, so blood cannot flow normal
• There are two main types:
• 1. Infant type – the narrowing is before the ductus arteriosus. Babies get sick
early, often with heart failure.
2. Adult type – the narrowing is after the ductus arteriosus. Patients live longer
because the body makes new blood vessels to help

Cont..
• What happens : “ When the aorta is narrow, blood to the upper body (arms and
head) is too much, causing high blood pressure. But blood to the lower body
(legs) is less, causing low blood pressure and weak pulse in the legs.”
symptoms: “The patient shows:
1. High blood pressure in the arms
2. Weak or delayed femoral pulse in the legs
3. Headache and nose bleeds
4. Cold feet or leg pain while walking”

Cont..
• Complications: “If not treated, the heart becomes big, brain vessels
can burst, and infection of the aorta may happen.”
Diagnosis: Doctors check the difference between blood pressure in
arms and legs. On X-ray we see rib notching and a figure 3 sign.
Echocardiography or CT scan confirms the disease.
Treatment: The treatment is surgery to remove the narrow part or
balloon angioplasty with stent to open it.

congenital heart diseases of burao university.pptx

congenital heart diseases of burao university.pptx

More Related Content

What's hot

Similar to congenital heart diseases of burao university.pptx

Recently uploaded

congenital heart diseases of burao university.pptx