Author: Sana Ullah, MB ChB, FRCA - Children’s Health, Dallas
A 36-year-old male who recently emigrated to the United States from India presents with worsening dyspnea on exertion and palpitations. He reports a history of rheumatic fever as a child. A 12-lead ECG show atrial fibrillation with a HR of 110. Transthoracic echocardiogram demonstrates a large secundum atrial septal defect with left to right shunting and moderate right heart enlargement. What additional abnormality is MOST likely to be seen on the echocardiogram?
The association of an atrial septal defect (ASD) with mitral stenosis (MS) is known as Lutembacher syndrome, named after the first publication in 1916 by a French physician. The ASD is usually congenital, but the MS is almost always due to a complication of rheumatic heart disease. Hence, this entity is more common in areas where rheumatic fever is endemic, such as sub-Saharan Africa and other under-developed countries. An iatrogenic form of Lutembacher syndrome is composed of a residual ASD created during trans-catheter balloon mitral valvuloplasty procedures for MS.
The natural history and hemodynamic sequelae of Lutembacher syndrome are determined by the size of the ASD, severity of MS, pulmonary vascular resistance, and compliance of the right ventricle. The magnitude of the left to right shunt across the typically large ASD is increased in the presence of severe MS resulting in volume overload of the right ventricle and pulmonary circulation. This will eventually result in right heart failure and pulmonary hypertension. In the presence of a restrictive ASD, the clinical course will be primarily determined by the severity of the MS. Atrial dilatation additionally predisposes patients to atrial fibrillation.
Diagnosis is confirmed by transthoracic echocardiography (TTE) and confirms ASD size and severity of MS. Planimetry is usually preferred in assessing MS severity as doppler gradients across the valve will be significantly reduced due to shunting across the ASD.
Treatment of Lutembacher syndrome in the current era is usually via trans-catheter techniques with balloon valvuloplasty of the mitral valve and device closure of the ASD. Surgical management is indicated for patients deemed unsuitable for trans-catheter procedure, such as inadequate rims around the ASD, left atrial thrombus, or concomitant severe mitral regurgitation.
In the patient described above, the most likely co-existing abnormality is MS due to the history of rheumatic heart disease. The mitral valve is the most common valve affected by rheumatic heart disease, initially causing mitral regurgitation that may progress to mitral stenosis. A significant ventricular septal defect is likely to result in pulmonary hypertension in a 36-year-old patient and reversal of shunting at level of the ASD. Therefore, answer B is incorrect. Partial anomalous pulmonary venous return is less likely in this patient with a history of rheumatic fever. Furthermore, PAPVR typially associated with sinus venosus ASDs rather than a secundum ASD.
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