从剖开的左心房可见最为普遍的原发性心脏肿瘤-心房粘液瘤。这些良性肿块大多附着在心房壁上，但也可以在瓣膜或心室出现。他们可以产生“球阀”效应，引起房室瓣口间歇性关闭。肿块的碎片也可能引发栓塞。超声心动图可容易诊断粘液瘤。
The left atrium has been opened to reveal the most common primary cardiac neoplasm--an atrial myxoma. These benign masses are most often attached to the atrial wall, but can arise on a valve or in a ventricle. They can produce a "ball valve" effect by intermittently occluding the atrioventricular valve orifice. Embolization of fragments of tumor may also occur. Myxomas are easily diagnosed by echocardiography.