[Obstructive sleep apnea syndrome with reversible interventricular septal displacement during sleep: a case report]

A case of the obstructive sleep apnea syndrome revealed reversible leftward displacement of the interventricular septum by echocardiography during sleep. A 46-year-old housewife with congenital micrognathia was admitted to our hospital complaining of severe dyspnea and general edema. On admission, she had severe hypoxemia (PaO2 = 35.2 mmHg), pulmonary hypertension (mean pulmonary artery pressure = 70 mmHg) and right heart failure. Her echocardiograms revealed enlargement of the right ventricle with a flattened left ventricle. A sleep study performed after partial resolution of her right heart failure disclosed that severe hypoxemia and pulmonary hypertension (mean pulmonary artery pressure = 70 mmHg) occurred after relatively long periods of apnea. With vigorous inspiratory efforts during sleep apnea, transient enlargement of the right ventricle and leftward displacement of the septum causing the flattened left ventricle were observed echocardiographically. A concomitant decrease in left ventricular inflow velocities was also observed by the pulsed Doppler method. However, these findings immediately returned to normal with the resumption of ventilation. We concluded that these repetitive apneic events due to obstruction of the airway during sleep might accelerate complete eventual pulmonary hypertension and right heart failure.