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A 35-year-old woman presented to the Adult Congenital Heart Disease Clinic 1 month after successful caesarean section (C-section) of her second child. A C-section was performed only as a result of fetal distress. She reported that compared to her prior pregnancy, symptoms of increasing shortness of breath in the third trimester that persisted postpartum. At the time of her initial outpatient clinic visit she experienced dyspnea with routine activities.

Her physical examination revealed the following vital signs: blood pressure (BP) 111/72 mm Hg, heart rate (HR) 74 bpm with 98% oxygen saturations in room air. Chest examination demonstrated no evidence of a right ventricular (RV) lift or heave. Cardiac examination demonstrated a regular rate and rhythm with a normal S1 and a fixed, split S2. The P2 component of the second heart sound was not accentuated. There was a soft II/VI systolic ejection murmur best appreciated at the left, upper sternal border. No diastolic murmurs, rubs, or gallops were heard. Extremities were warm and well perfused without clubbing, cyanosis, or edema.

A 12-lead electrocardiography (ECG) demonstrated a normal sinus rhythm, normal axis, and incomplete right bundle branch pattern (Figure 2-1). A transthoracic echocardiogram (TTE) demonstrated right atrial and ventricular enlargement (Figures 2-2 and 2-3) as a consequence of a large atrial septal defect, secundum type.


A 12-lead electrocardiogram demonstrates a normal sinus rhythm with an incomplete right bundle branch block.


Right ventricular inflow view demonstrating moderate right atrial and ventricular enlargement on outpatient 2-dimensional transthoracic imaging. RA, right atrium; RV, right ventricle.


Apical 4-chamber view on a transthoracic echocardiogram with right atrial and ventricular chamber enlargement (left) and left-to-right shunt with color Doppler interrogation suggestive of secundum-type defect (right). RA, right atrium; RV, right ventricle.


  • Patients with an atrial septal defect (ASD) often have fixed splitting of the second heart sound. However, its absence does not exclude an ASD. The absence of a loud P2 component of the second heart sound minimizes the possibility of pulmonary hypertension. The systolic ejection murmur is consistent with increased pulmonary blood flow.

  • The incomplete right bundle branch block pattern on 12-lead ECG suggests right ventricular volume overload.

  • Findings of right atrial and ventricular enlargement on echocardiogram should prompt an evaluation for possible ASD.


  • ASDs are common and can present at any age. Interatrial communications are the third most common type of congenital heart defect and the type most likely to be diagnosed in adulthood.

  • Female gender constitutes 65% to 75% of patients ...

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