Sinus Venosus Atrial Septal Defects Clinical Presentation

Updated: Dec 15, 2020
  • Author: Gary M Satou, MD, FASE; Chief Editor: Howard S Weber, MD, FSCAI  more...
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Sinus venosus atrial septal defects (ASDs), like most ASDs, are diagnosed upon detection of a murmur, a fixed split second heart sound, and/or right heart enlargement on chest x-ray or electrocardiogram (ECG) in the usually asymptomatic patient. Note the following:

  • Symptoms of ASDs are typically a function of the size of the associated shunt.

  • As many as 60% of apparently asymptomatic patients may have easy fatigability and dyspnea. Such symptoms usually indicate a relatively large shunt.

  • Adults may not come to medical attention until symptoms occur. Arrhythmias, dyspnea, and a decrease in exercise tolerance are common symptoms.



A cardiac murmur secondary to increased pulmonary artery blood flow is heard over the upper left sternal border. The murmur is usually a soft grade 2/6 systolic ejection murmur. A prominent right ventricular impulse may also be noted along the left sternal border. A diastolic flow murmur may be present at the left lower sternal border and the tricuspid area and is indicative of a large left-to-right shunt.

The second heart sound is widely split and may be fixed or may vary little with respiration. The pulmonic component of the second heart sound is usually normal in intensity but may increase in intensity if pulmonary hypertension is present.

Patients with atrial septal defects may present with the "gracile habitus." These patients are thin for their height.