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Showing posts with label atrial septal defect. Show all posts
Showing posts with label atrial septal defect. Show all posts

Management of ASD

Definitive treatment of ASD is closure with patch of defect.
Repair of ASD defect is indicated
  • When there is significant shunt from left atrium to left ventricle with pulmonary blood flow to systemic blood flow is >2:1.
Contraindications to surgical treatment are
  • Small ASD with bivial shunt
  • ASD with severe PAH, and right to left shunt pulmonary  vascular resistance to systemic vascular resistances >0.7:1

What is the effect of PAH on physical signs of ASD ?

When the person with ASD develop PAH. The following effects are noticed.
Prominent a wave is present in JVP.
Split of S2 narrows.
Two new sounds appear they are pulmonary ejection click (PEC) and right ventricular S4 (RVS4)
Two murmur disappeares they are pulmonary ejection systolic murmur and tricuspid mid diastolic murmur.
Two new murmurs appear 
  • Tricuspid pansystolic murmur
  • Pulmonary early diastolic murmur
Usually with fixed split of S2 narrows with ASD with PAH, but when ASD with PAH is in RV failure (Right ventricular) wide fixed split is retained.

What are the complications of ASD ?

Common complications in ASD are
  • Pulmonary artery hypertension
  • Cardiac failure
  • Atrial arrhythmia (atrial fibrillation or flutter)
Rare complications in ASD are
  • Rare complications of ASD are infective endocarditis.
Endocarditis is more common in ostium primum defect and in ostium secundum defect associated mitral valve prolapse. Other complications are Eisenmenger syndrome and paradoxic embolism.
The most common cause of death in AD is cardiac failure. 
Right heart failure is seen in ASD in patients above 30 years. It may be precipitated by
  • Decreased LV compliance as a result of hypertension or coronary artery disease
  • Atrial arrhythmia

Read related topics -ASD

What are the investigation findings in ASD (atrial septal defect) ?

The main diagnostic modalities of ASD are ECG, chest X-ray and echocardiogram.
The findings are listed below.
ECG findings in ASD
  • There is right axis deviation in ECG. Axis may be deviated to left in ostium primum defet.
  • Right bundle branch block (RBBB)
RBBB is due to delayed activation of the posterobasal part of ventricular septum and due to enlarged ventricular outflow tract.
Chest X-ray findings in ASD
Chest X-ray will show
  • Enlarged right atria and right ventricle
  • Prominence of main pulmonary artery
  • Pulmonary plethora
Chest X-ray also help to differentiate between mitral stenosis and ASD. Left atrial enlargement is the striking features of MS which is absent in ASD.
Echocardiograpy in ASD
Echocardiography shows  the definitive features of ASD
  • Right ventricular dilatation
  • Paradoxical septal motion
Subcostal echo is best in visualising the defect
2D- echo with Doppler is the confirmatory diagnostic test
Transesophageal echo: Useful in ambiguous transthoracic  Echo.
Cardiac catheterisatiom in ASD is done in case of
  • Coronary artery disease
  • Valvular heart disease
  • Pulmonary artery hypertension.

Read related topics -ASD

What is the Hemodynamics in ASD ?

The essential hemodynamic feature of ASD is right ventricular volume overload.
When there is RV volume overload it produces the following effect.
  • Right ventricle compress on the let ventricle producing reverse Bernheim effect on the interventricular septum.
  • Right ventricle compress on the coronary arteries.
What are the main fectors that determine the shunt in ASD
Shunt in ASD is determined by
  • Size of septal defect
  • Relative distensibility of the left and right ventricle.
  • Pulmonary as well as systemic vascular resistance.
Large septal defect produce the following effects
  • Cardiomegaly 
  • Load ejection systolic murmur with thrill in the pulmonary area
  • Tricuspid midiastolic murmur
These three factors are used to access the size of ASD
Describe about ASP with bidirectional shunt
This is ASD with shunt occurring in either direction, based on pulmonary and systemic vascular resistance.

What are the Murmurs in atrial septal defect?

ASD is a condition where there is abnormal communication between the right and left atria resulting in shunting of blood from left to right atria.
What is the classical murmur of atrial septal defect ?
The classical murmur is a crescendo - decrescendo ejection systolic murmur in the pulmonary area which peaks in early or mid systole.
This murmur is produced due to the rapid ejection of the large right ventricular stroke volume into the dilated pulmonary artery.
Sometimes flow murmur may be produced due to rapid blood flow through the peripheral pulmonary arteries. This can be heard as a systolic murmur over the right side of chest, axilla or back.
What are the causes of loud murmur in ASD ?
Loud murmur in ASD may be due to 
  • Large defect
  • ASD with mitral stenosis
  • ASD with pulmonary stenosis
What are the differential diagnosis of mid diastolic murmur at apex in ASD ?
Large ASD with tricuspid middiastolic murmur
ASD with acquired mitral stenosis
Differential diagnosis of ASD with PSM (Pansystolic murmur) at the apex - following are the causes ?
Ostium secondum ASD with mitral valve prolapsed
Ostium primum ASD with mitral regurgitation

Why there is Fixed split in ASD

Split is fixed in ASD because of the following reasons.
1.Septal defect produce equalisation of pressure between the atria during the respiratory cycle.
2.The hangout interval is already widened. Ti cannot be further increased during inspiration.
What is the prerequisite before diagnosing wide fixed split 
Before diagnosing the fixed split always examine the patient in the standing or sitting position, because the split tend to be narrow on standing due to shortening of right ventricle ejection time more than left ventricle.

How will you clinically diagnose atrial septal defect?

Atrial septal defect is the most common congenital heart disease in adult.
It can be diagnosed based on clinical symptoms and signs.
The most common symptoms of ASD are
  • Dyspnoea on exertion
  • Palpitation
  • Recurrent chest infection 
Examination will show the following features
Pulse, blood pressure and jugular venous pressure are normal
Precordial bulge may be seen
Apex beat is normal.
P2 is palpable and pulmonary artery pulsation may be felt
Systolic thrill may be present in 2nd left inter costal space
Left parasternal heave present 
On auscultation 
S1 is loud
P2 is loud
Wide fixed split of S2 is present
There may be an ejection systolic murmur (ESM)which is heard at the pulmonary area 
The striking features are
  • Palpable P2
  • Left parasternal heave
  • Systolic thrill in 2nd left intercostals space
  • Wide fixed split S2
  • ESM in pulmonary area
What are the causes of thrill in ASD?

Development of interatrial septum and its defect (ASD)

Atrial septal defect is the most common congenital heart diseases in adults. Intratrial septum is developed from septum primum and septum secundum.
Septum primum forms the lower part of atrial septum
Septum secundum forms the upper part of atrial septum.

There are 4 different types of atrial septal defect which include :
  • Ostium secundum type of ASD seen in 70% cases.
  • Ostium primium type of ASD seen in 20% case
  • Sinus venosus type
  • Coronary sinus type
Ostium secundum type of ASD is developed from septum secondum which is also called as fossa ovalis.
Ostium primum type of ASD develops from septum primum. It is also called as partial AV canal defect.
Sinus venosus type is situated superior to fossa ovalis in relation to the superior venocaval opening into the right atrium. 
Coronary sinus type the defect is seen near the opening of coronary sinus.

Following associations are seen in atrial septal defect
Ostium secundum – May be associated with mitral valve prolapse and partial anomalous pulmonary venous connection on right side.
Ostium primum ASD – is associated with left mitral or tricuspid valve and first degree heart block.
Sinus venosus ASD –may be associated with partial anomalous pulmonary venous connection.
Coronary sinus – May be associated with superior venacaval opening into left atrium.
Syndromes in relation to atrial septal defect
Down syndrome patients have higher rates of ASDs, 
Ebstein's anomaly about50% of individuals with Ebstein anomaly have an associated shunt between the right and left atria, either an atrial septal defect or a patent foramen ovale.
Fetal alcohol syndrome 25% of patients with fetal alcohol syndrome has either an ASD or a ventricular septal defect.
Holt-Oram syndrome – Both the osteium secundum and osteum primum types of ASD are associated with Holt–Oram syndrome
Lutembacher's syndrome – the presence of a congenital ASD along with acquired mitral stenosis.

SCIMITAR syndrome
What is SCIMITAR syndrome: Here there is fatal or patial anomalous pulmonary venous drainage into the inferior venacava

Lutembacher syndrome 
It is congenital ASD with acquired mitral stenosis.

Development of interatrial septum

Through all stages of development of fetus blood shunts from right atria to left atrium so it bypass lungs.
Inter atrial septum is developed from  Septum Primum and Septum Secundum
Septum Primum
Septum Primum is a crescent shaped membranous extension of dorso-cranial wall. 
It will grows downward towards endocardial cushions
The opening between the Septum Primum and endocardial cushions is foramen primum (ostium primum), which  serves as a shunt.
A series of perforations will develop in cranial end that coalesce to form foramen secundum (ostium secundum)
In the later stages of development the septum primum fuses with endocardial cushions – this will obliterates foramen primum
Septum Secundum
Septum Secundum is a crescent shaped septum begins to form to the right side of of septum primum
Grows as septum primum downwards, it does not fuse with endocardial cushion, the opening is called foramen ovale
Because of the arrangement of the two septa it act as one-way valve.

Types of ASD (Atrial septal defect)

 Atrial septal defect (ASD) is a defect in the interatrial septum permitting free communication of blood between the atria. Based on the location of the septal defect ASD can be classified into four types.

  1. Ostium secundum ASD is the commonest type of ASD which involves the fossa ovalis, in the mid-septal region. 20% of these cases are associated with mitral valve prolapse (MVP). 
  2. Ostium primum type of ASD is rare, defect is near AV valves. The AV valves may also be deformed.
  3. Sinus venosus type is also rare, defect is seen high in the atrial septum near the entry of superior venacava (SVC).
  4. Coronary sinus type of ASD