因心脏过早收缩而引起的一次心脏提前跳动。是一种常见的心脏疾病premature atrial contraction

• B超显示胎盘没有早搏现象。

  A B-mode ultrasound shows that there are no premature atrial contractions in the placenta.

• 心脏彩超显示，他心律出现早搏异常。

  A heart colour ultrasound showed that his heartbeat was showing unusual premature atrial contractions.