Response to Dr Kula: Asymptomatic hypoxia in a young pregnant lady—Unusual presentation of atrial septal defect

Abstract

We thank Dr Kula and colleagues for their comments [1] on our recent case report ‘Asymptomatic hypoxia in a young pregnant lady—an unusual presentation of atrial septal defect [2]’. The patient described was noted to have an ejection systolic murmur in the pulmonary area with fixed wide splitting of the first heart sound without a loud pulmonary component on clinical examination. A bubble contrast echocardiography which was done as a diagnostic procedure did demonstrated passage of a few bubbles (b5) from the right to left atrium even at rest before a Valsalva manoeuvre but bubbles were more pronounced with the Valsalva manoeuvre (N20) consistent with the diagnosis of an atrial septal defect (ASD) without any evidence of pulmonary hypertension. We agree that the passage of bubbles from right to left side at rest is very common in patients with pulmonary hypertension but still could be seen in patients with large atrial septal defects, as seen in our case. At 3 months after pregnancy, a transoesophageal echocardiography examination demonstrated a Qp/Qs ratio of 1.7:1 without any features suggestive of pulmonary hypertension. She did not undergo any right or left heart catheterisation due to the lack of pulmonary hypertension, well delineated os secundum ASD on echocardiography and a low risk for coronary artery disease. Following referral to a tertiary centre, she had an uncomplicated percutaneous closure of her ASD. We believe that the hypoxia noted during her pregnancy and just immediately post-partum might well be related to transient right to left sided shunting, but after the device closure of the ASD, a subsequent TOE did not demonstrated any residual shunting. There was no further hypoxia after procedure which was confirmed in her arterial blood gas analysis. We agree with Dr Kula colleagues that a differential diagnosis to consider in this kind of scenario is a pulmonary atrio-venous malformations or fistula, as a fifth of patients do remain asymptomatic. This diagnosis was considered in our patient but the subsequent investigations clearly revealed the presence of large os secundum ASD. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology [3].