Dynamic right ventricular outflow tract obstruction due to straight back syndrome and funnel chest - A pediatric case.

Thoracic deformity affects circulatory dynamics, and postural changes may affect hemodynamics. We report on the case of a 10-year-old girl with straight back syndrome (SBS) and funnel chest in which a right ventricular outflow tract (RVOT) obstruction was demonstrated by dynamic echocardiography. The patient occasionally experienced chest discomfort in the standing and sitting positions. Chest radiography and computed tomography showed SBS and funnel chest as well as limited anteroposterior chest space. Although she had a grade 3 systolic ejection murmur due to RVOT obstruction, it disappeared in the supine position. The cardiothoracic ratio was 56 % in the supine position but increased to 67 % in the upright position. Echocardiography showed that the RVOT was maintained in the supine (1.0 m/s) but narrowed in the sitting (1.7 m/s) position. This is the first pediatric case showing RVOT obstruction during the upright position that has been shown by dynamic echocardiography. Dynamic echocardiography in both positions may be useful for evaluating RVOT stenosis. Learning objective: Patients with straight back syndrome and funnel chest have limited anteroposterior chest space, which may cause posture-dependent right ventricular outflow tract (RVOT) obstruction. Dynamic echocardiography in the supine and sitting position is useful to detect posture-dependent RVOT obstruction, which can be also observed in the pediatric population.