Right Ventricle Pressure Overload Induces Tethering of the Mitral Valve: the Case Report of a Neonate with Congenital Mitral Valve Dysplasia

Mitral stenosis and regurgitation (MSR) induced by congenital mitral valve dysplasia generally necessitates surgical repair or valve replacement. Here we report the case of a female infant diagnosed with congenital MSR that improved with pharmacotherapy alone and without a mitral valve surgery. The patient was a 22-day-old girl diagnosed with severe MSR accompanied with over-systemic pulmonary hypertension (PH). She was treated with respiratory support using a high-flow nasal cannula; diuretics and digitalis were also administered. Unexpectedly, the patient’s MSR and PH alleviated, and surgery was avoided. Tethering of the mitral valve induced by left ventricular dilation is known to result in secondary mitral regurgitation in adult ischemic heart disease. We speculated that the underlying mechanisms of MSR in this case: were due to elevation of the right ventricular pressure caused by physiological and pathological PH, which is a result of papillary muscle displacement and tethering of the mitral valve. We consider this the reason for the appearance of MSR on admission. Differentiating functional MSR from organic MSR is crucial while making decisions regarding surgery.