Atrial Septal Defects and Congestive Cardiac Failure

Presentation and Diagnosis

Children with large atrial septal defects (ASD) and congestive cardiac failure (CCF) typically present with progressive feeding intolerance, failure to thrive, exertional dyspnea, and recurrent "chest infections" 1
Hepatomegaly from right heart failure is a characteristic sign of CCF in pediatric ASD patients 1
Fixed splitting of the second heart sound is pathognomonic for ASD 1
A diastolic tricuspid flow rumble indicates significant shunt with Qp/Qs >2.0 1
ECG shows right axis deviation, incomplete right bundle branch block, right atrial enlargement, and right ventricular hypertrophy 1
Chest X-ray demonstrates increased pulmonary vascularity bilaterally, cardiomegaly, and enlarged pulmonary artery segment 1
Right ventricular enlargement on echocardiography is the primary indicator of hemodynamically significant shunting 1, 2
Any adult presenting with atrial arrhythmia and dilated RV should be investigated for an atrial level shunt lesion 3

The fundamental mechanism of CCF in ASD is right ventricular volume overload from chronic left-to-right shunting 1, 4
The left-to-right shunt causes increased blood flow through the right heart, leading to RV volume overload and pulmonary overcirculation 4
Closure of ASD with evidence of right heart volume overload is indicated regardless of symptom status to prevent progression to overt heart failure 2
Surgical or device closure is indicated for Qp/Qs >1.5 with RV volume overload 1
Closure should not be performed in patients with severe irreversible pulmonary hypertension and no evidence of left-to-right shunt 2

Adults with large ASDs typically develop symptoms in the third decade of life or later, with CCF occurring through multiple pathophysiologic mechanisms 2, 3
Reduced LV compliance from ischemic heart disease, hypertension, or diabetes mellitus increases LV diastolic and left atrial pressure, leading to increased left-to-right shunting with pulmonary overcirculation that can accelerate RV failure 3
Superimposed pulmonary disease including interstitial lung disease or obstructive sleep apnea adversely affects RV function 3