Atrial Septal Defect (ASD)

Atrial septal defect (ASD) is a type of congenital heart disease that enables blood flow between two upper compartments of the heart called the left and right atrium. Normally, the right and left atriums are separated by a septum called the inter-atrial septum. If this septum is defective or absent, then oxygen-rich blood can flow directly from the left side of the heart to mix with the oxygen-poor blood in the right side of the heart, or vice versa. However, an Atrial Septal Defect (ASD) may not produce noticeable signs or symptoms, especially if the defect is small.

Symptoms of Atrial Septal Defect (ASD)

In Children

Usually asymptomatic

Large defects may cause

Congestive heart failure,Recurrent respiratory infection,Exertional dyspnoea (Difficulty in breathing while doing any physical activities), fatiguability

In Adults

Palpitation-Fast beating of the heart,(Atrial fibrillation),Excertional dyspnoea (Difficulty in breathing while doing any physical activities),Eisenmenger’s syndrome (The process in which a left to right shunt caused by a congenital heart defect in the fetal heart)

Physical Examination

JVP (Jugular Venous Pulse)-V wave prominent (left atrium patter),Right ventricular (lower chamber of the heart)  lift,Palpable pulmonary artery pulsation,Wide and fixed splitting S2-second heart sound (A2-P2 do not move close on expiration),Pulmonary soft superficial ejection systolic murmur in second left intercostals space, radiating to left shoulder,Tricuspid mid-distolic flow murmur when shunt > 2:1,Right sided S3 in large left to right shunts,Mitral incompetence in ostium primum defect.

X-Ray

Increased pulmonary vascularity,Enlarged main pulmonary artery,Small ascending aorta,Right ventricular enlargement,LA enlargement in ostium primum defect

Echo

 

Dilated RV, RA and LA,Paradoxical septal motion (RV volume overload),Inter artrial shunt shown by contrast / colour Doppler,Visualization of the defect.

Treatment

Shunt closure by Septal occluder shown in figure below if shunt exceeds 1.5:1 but not for Eisenmenger syndrome.

Dacron patch repair or transvenous umbrella closure when thoractomy contraindicated.

 

Associated Defects

MVP in 20% cases of Secundum ASD,Lutembacher syndrome – ASD with mitral stenosis,Triology of Fallot-ASD + Pulmonary stenosis + RVH,Pentalogy of Fallot- ASD+Fallot tetralogy

Signs of a Developing Eisenmenger Complex

Decreasing intensity of pulmonary / tricuspid flow murmurs,Increasing intensity of P2 : development of single S2.,Appearance of Graham-Steel murmur(A heart murmur typically associated with pulmonary regurgitation. It is a high pitched early diastolic murmur heard best at the left sternal edge in the second intercostal space with the patient in full inspiration.),Development of central cyanosis-the appearance of a blue or purple coloration of the skin or mucous membranes due to the tissues near the skin surface being low on oxygen,Clubbing-also known as drumstick fingers and watch-glass nails (later)

In Further

Type	Location	ECG-Feature	Associated Abnormalities
Primum	Lower septum A.V. Valve	Left axis deviation, AV block	Cleft mitral valve
Secundum	Fossa ovalis	Incomplete RBBB normal or right axis	Mirtal valve prolapse
Sinus Venosus	High atrial septum near SVC	Ectopic atrial rhythm, negative P in lead III	Annomalous pulmaonary venous connections