【名词&注释】
心房颤动(atrial fibrillation)、预激综合征(preexcitation syndrome)、利多卡因(lidocaine)、心房扑动(atrial flutter)、心得安(propranolol)、高度房室传导阻滞(advanced atrioventricular block)、抗心律失常药物(antiarrhythmic drug)、肺动脉瓣(pulmonary valve)、美西律(慢心律)、洋地黄制剂(digitalis)
[单选题]有关肺动脉瓣(pulmonary valve)口的描述,正确的是
A. 肺动脉瓣(pulmonary valve)由2个瓣叶组成
B. 肺动脉瓣(pulmonary valve)由3个瓣叶和3组小乳头肌组成
C. 肺动脉瓣(pulmonary valve)口由肺动脉瓣(pulmonary valve)环和3个半月形肺动脉瓣(pulmonary valve)组成
D. 肺动脉瓣(pulmonary valve)口直接与右室流入道相连续
E. 肺动脉瓣(pulmonary valve)口向下通过宽大的右室流入道与右室相连