Questions on atrial septal defect (ASD)

Definition and classification

  • What is wide and fixed splitting of 2nd sound? A, hs
  • What are the types of ASD? A, hs
  • What is Lutembacher’s syndrome? A
  • What is patent foramen ovale? Hs
    • What is the main difference between patent foramen ovale and ADS? Hs
  • What is Holt-Oram syndrome? hs

Epidemiology

  • Q

Etiology and Pathophysiology

  • Why does wide and fixed splitting occur in ADS? A, hs
  • What are the murmurs in ASD? A, hs
  • Why no murmur due to ASD itself? hs

Clinical manifestations

  • What murmur may be heard in patient with ADS? Hs

Examinations

  • What are the findings when there is reversal of shunt? A, hs
    • At what age shunt reversal usually occur? Hs
  • What are the auscultatory findings of ASD and VSD? H192

Investigations

  • What investigations do you suggest in ASD? A, hs
  • What is the ECG finding in ASD? A, hs
  • What is the X-ray finding in ASD? hs

Diagnosis

  • Which type of ASD do you think clinically? hs
  • What are your differential diagnoses? A, hs
  • Why not this is a case of pulmonary stenosis? A, hs
  • Why not this is a case of VSD? A
  • A patient with MS also has ASD. What may be the possibilities? hs

Treatment

  • How to treat ASD? A, hs
  • How can you treat secondary pulmonary hypertension? Hs
  • What are the indications for ASD closure? Hs
  • Is the development of Eisenmenger’s syndrome always contraindication fro ASD closure? hs

Complications

  • What are the complications of ASD? A, hs

 

 


Rimikri

SOLVES


Definition and Classification
What is wide and fixed splitting of 2nd sound?

Wide means that gap between A2 and P2 is wider than usual and fixed splitting means no variation during respiratory cycle, i.e. it remainins same in inspiration and expiration.

See more about heart sound at Examination of cardiovascular system.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 55

What are the types of ASD?

They are of two types:

  1. Ostium secundum (90% cases)
    • Defect is mainly at the fossa ovalis.
  2. Ostium primum ( 10% cases)
    • It results from atrioventricular defect in septum and there is involvement of AV valve; hence there may be MR or TR.
  3. Other
    • Sinus venosus ASD
    • Coronary sinus ASD

Note

  • ASD is common in females; M:F ratio is 1:2.
  • Ostium primum may occur in Down syndrome.
* Short Cases in Clinical Medicine, ABM Abdullah, 5th Edition Page: 99; Short and Long Cases in Clinical Medicine, HN Sarker Page: 54
What is Lutembacher’s syndrome?

ASD with an acquired rheumatic mitral stenosis.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 247
What is patent foramen ovale?

Patent foramen ovale (PFO) is a remnant of the fetal circulation (25-30%).

It is an oblique slit-like defect in interatrial septum due to incomplete fusion of septum primum against septum secundum and functions as a valve-like structure with the door jam on the left atrial side of the interatrial septum.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 56
What is the main difference between patent foramen ovale and ADS?

PFO does not allow equalization of pressure between left and right atrium unlike ASD.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 56
What is Holt-Oram syndrome?

It is an autosomal dominant condition, characterized by ASD (osdum secundum) with absence or short upper limb, a hypoplastic thumb with an accessory phalanx.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 56
Epidemiology
Etiology and Pathophysiology
Why does wide and fixed splitting occur in ADS?
  • Wide: Because of delay in right ventricular ejection (increased stroke volume and right bundle branch block) and
  • Fixed: Because the septal defect equalises left and right atrial pressures throughout the respiratory cycle.

Note:

Normally, there is wide splitting during inspiration due to delay of closure of pulmonary valve.

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 633; Long Cases in Clinical Medicine, ABM Abdullah Page: 246
What are the murmurs in ASD?

Two murmurs:

  • ESM
    • It is due to increased flow through pulmonary valve
    • ESM is typical of ASD
    • It does not occur due to septal defect
  • MDM
    • MDM in left parasternal area is due to increased flow through tricuspid valve
    • Its presence indicates hemodynamically significant shunt.

Note:

No murmur is due to ASD. Because there is equal pressure between left and right atrium.

Read more about murmur at Examination of cardiovascular system

* Long Cases in Clinical Medicine, ABM Abdullah Page: 246; Short and Long Cases in Clinical Medicine, HN Sarker Page: 56
Why no murmur due to ASD itself?

There is no murmur due to ASD, because of equal pressure between left and right atrium.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 56
Clinical Manifestations
What are the clinical manifestations of ASD?

Clinical Manifestations

Vary with the size of defect.

  • Small defect : Asymptomatic and is usually diagnosed during a routine health check-up
  • Large defect : Symptomatic & patients usually present with–
    • Easy fatigability
    • Increased perspiration
    • Poor weight gain (failure to thrive)
    • Recurrent respiratory tract infections
* Step on to Paediatrics, Md Abid Hossain Mollah, 3rd Edition Page: 123
Examination
What are the examination findings of a patient with ASD?

General physical examination

  • Appearance : Usually normal
  • Heart rate : Normal
  • Respiratory rate : Normal
  • Weight & height : Age appropriate
  • Pulse: 86/min, normal in volume, rhythm and character.
  • JVP: Normal.
  • BP: 120/75 mmHg.

Precordium:

On inspection:

  • Usually normal.

On palpation:

  • Apex beat: In left … intercostal space, … cm from midline.
  • Thrill: Absent.
  • (Apex beat may be shifted to left, P2 may be palpable, left parastemal heave may be present)

On auscultation:

  • First heart sound (S1): normal in all the areas.
  • Second heart sound (S2): Widely splitted and fixed (very important finding).
  • Added sound:
    • There is an ejection systolic murmur in left second and third intercostal spaces (in pulmonary area).
    • There is ( or may be) MDM in tricuspid area.
* Short Cases in Clinical Medicine, ABM Abdullah, 5th Edition Page: 98; Step on to Paediatrics, Md Abid Hossain Mollah, 3rd Edition Page: 123
What are the examination findings when there is reversal of shunt?

As follows:

  • Cyanosis
  • Clubbing
  • Both murmurs are reduced in intensity (becomes quite)
  • Systolic ejection sound is accentuated
  • Features of pulmonary hypertension, e.g. loud P2, left parasternal heave, etc.
* Long Cases in Clinical Medicine, ABM Abdullah Page: 246; Short and Long Cases in Clinical Medicine, HN Sarker Page: 57
At what age shunt reversal usually occur?

Shunt reversal usually occurs after 20 years of age.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 57
What are the auscultatory findings of ASD and VSD?
  • ASD—Ejection systolic murmur in pulmonary area
  • VSD—Pansystolic murmur in left parasternal area.
* Pre-exam preparation for medicine, HN Sarker
Investigations
What investigations do you suggest in ASD?

As follows:

  • Chest X-ray
  • ECG
  • Echocardiogram (shows location and size of the defect)
  • Cardiac catheterization in some cases
* Short and Long Cases in Clinical Medicine, HN Sarker Page: 56; Step on to Paediatrics, Md Abid Hossain Mollah, 3rd Edition Page: 123
What is the ECG finding in ASD?

ECG shows the following

  • May be normal, especially in small defects.
  • Incomplete right bundle branch block
  • Right axis deviation (in ostium secundum defects)
  • Left axis deviation (in ostium primum defects)

Other findings may be as follows

  • Right ventricular hypertrophy
  • Right atrial hypertrophy (P pulmonale)
  • Left atrial enlargement (biphasic p waves in V1).
* Short and Long Cases in Clinical Medicine, HN Sarker Page: 56; Step on to Paediatrics, Md Abid Hossain Mollah, 3rd Edition Page: 123
What is the X-ray finding in ASD?

The X-ray findings in ASD are as follows:

  • Normal or may show cardiomegaly
  • Cardiomegaly with plethoric lung fields
  • Cardiomegaly with oligemic lung fields when pulmonary hypertension develops
* Short and Long Cases in Clinical Medicine, HN Sarker Page: 56; Step on to Paediatrics, Md Abid Hossain Mollah, 3rd Edition Page: 123
Diagnosis
Which type of ASD do you think clinically?

Example:

Ostium secundum, because ostium primum is usually associated with mitral and/ or tricuspid regurgitation.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 55
What are your differential diagnoses?

As follows:

  • Pulmonary stenosis
  • VSD
* Long Cases in Clinical Medicine, ABM Abdullah Page: 245
Why not this is a case of pulmonary stenosis?

Clinically differences between ASD and pulmonary stenosis:

Feature ASD Pulmonary stenosis
Thrill Absent Systolic thrill present in pulmonary area
S2 Fixed, wide splitting Wide but no fixed splitting
P2 Normal P2 is soft or absent
ESM Does not radiate to the neck Radiates to the neck
* Short and Long Cases in Clinical Medicine, HN Sarker Page: 56
Why not this is a case of VSD?

In VSD, the findings are:

  • Systolic thrill in the left lower parasternal area
  • Pansystolic murmur in the left lower parasternal area.
* Long Cases in Clinical Medicine, ABM Abdullah Page: 245
A patient with MS also has ASD. What may be the possibilities?

Possibilities are as follows

  • Lutembacher’s syndrome (Congenital ASD with acquired rheumatic mitral stenosis)
  • Iatrogenic ASD with acquired rheumatic mitral stenosis [with previous history of mitral valvuloplasty (PTMC), which requires a transeptal puncture to gain access to the left heart from a venous (femoral) route].
* Short and Long Cases in Clinical Medicine, HN Sarker Page: 56
Treatment
How to treat ASD?

Counsel the parents about the disease, treatment options and prognosis.

  1. Small defects with normal pulmonary artery pressure
    • Re-assurance
    • Encourage to lead a normal life.
  2. Larger defects with pulmonary hypertension/right ventricular failure
    • Diuretics for heart failure
      • Diuretics : Frusemide, Thiazide or combination to remove excess fluid from the body through urine
      • Digoxin : Helps to strengthen the heart muscle, enabling it to pump more efficiently
    • Treatment of pulmonary hypertension
    • ASD closure (surgical or percutaneous) if no contraindications.
* Step on to Paediatrics, Md Abid Hossain Mollah, 3rd Edition Page: 123; Short and Long Cases in Clinical Medicine, HN Sarker Page: 57
How can you treat secondary pulmonary hypertension?

Treatment includes

  • Treatment of underlying cause
  • Diuretics for congestive heart failure
  • Long-term oxygen therapy
  • Anticoagulation
  • Vasodilator therapy
    • Calcium channel blockers-nifedipine and dilatiazem
    • Nitric oxide inhalation
    • Prostacyclin analogs- Epoprostenol and Treprostinol (intravenous preparations), Iloprost (nebulized inhalation)
    • Adenosine infusion
    • Nitrate infusions
    • Phosphodiesterase-5 inhibitors, e. g. sildenaftl
    • Endothelin antagonists. Oral bosentan.
* Short and Long Cases in Clinical Medicine, HN Sarker Page: 57
What are the indications for ASD closure?

Surgical closure should be done, if pulmonary flow to systemic flow is 2:1 or more (Qp : Qs > 2 : 1).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 247; Short and Long Cases in Clinical Medicine, HN Sarker Page: 57

Atrial septal defects in which pulmonary flow is increased 50% above systemic flow (i.e. flow ratio of 1.5 : 1)

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 633
Is the development of Eisenmenger’s syndrome always contraindication fro ASD closure?

If the pulmonary hypertension is irreversible, then closure is contraindicated if reversible pulmonary hypertension, then closure may be undertaken.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 57
Complications
What are the complications of ASD?

The complications of ASD are as follows:

  • Pulmonary hypertension
  • Eisenmenger’s syndrome (reversal of shunt)
  • Atrial arrhythmias (atrial fibrillation is the most common)
  • Paradoxical embolism
  • Brain abscess
  • Infective endocarditis
  • Recurrent pulmonary infections.

Note:

Paradoxical embolism transit from right- to left-sided cardiac chambers, may occur via interventricular, interatrial, or pulmonary arteriovenous malformations.1

A paradoxical embolism is a blood clot that does not travel with normal blood flow. Normally, blood flows from the right side of the heart through the pulmonary arteries and lungs before it returns to the left side of the heart. But this type of embolism moves directly from the right side of the heart to the left through a hole (defect) in the septum.2 Direct entry of venous blood to systemic circulation bypassing lungs may lead to brain abscess.3

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 56; 1 ahajournals.org 2 webmd.com 3Step on to Paediatrics, Md Abid Hossain Mollah, 3rd Edition Page: 129
Notes
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