atrioventricular (AV) nodal extra systole

a·tri·o·ven·tric·u·lar (AV) no·dal ex·tra· sys·to·le

(ā'trē-ō-ven-trik'yū-lăr nō'dăl eks'tră-sis'tŏ-lē)

A premature beat arising from the AV junction and leading to a simultaneous or almost simultaneous contraction of atria and ventricles.