In a 1-day old filly with a loud heart murmur, transthoracic echocardiography revealed right ventricular hypertrophy associated with severe pulmonary valvular stenosis and a transvalvular pressure gradient (between right ventricle and pulmonary artery) of 125 mmHg. Computed tomographic angiography confirmed the finding, with no evidence of other relevant concurrent abnormalities. Balloon valvuloplasty was performed using a single balloon technique. The foal recovered well from anaesthesia. Following the procedure, the right ventricle-pulmonary artery transvalvular gradient decreased to 38 mmHg. At follow up examinations after 1 month, 1 year and 2 years, the filly showed normal exercise capacity and echocardiography confirmed the persistent substantial improvement in the transvalvular outflow gradient.

一头 1 天大的母马心脏杂音很大，经胸超声心动图显示右心室肥厚与严重的肺动脉瓣狭窄和跨瓣压力梯度（右心室和肺动脉之间）为 125 mmHg。计算机断层扫描血管造影证实了这一发现，没有其他相关并发异常的证据。球囊瓣膜成形术使用单球囊技术进行。小马驹从麻醉中恢复良好。手术后，右心室-肺动脉跨瓣压差降至 38 mmHg。在 1 个月、1 年和 2 年后的随访检查中，小马显示出正常的运动能力，超声心动图证实跨瓣流出道梯度持续显着改善。