Acute pericarditis generally lasts just a few weeks, whereas chronic pericarditis lasts longer, usually more than 6 months.

急性心包炎通常持续数周时间，而慢性心包炎持续时间较长，大于6个月。

Now, the cause of acute pericarditis is usually idiopathic, meaning that we don't know what causes it.

急性心包炎通常是特发性的；特发性指原因不明。