This is the most common cause of an unusual,or abnormal, heartbeat in older adults.

VOA: special.2009.09.22

A desperate honesty that throbs through his confession does not absolve him from sins of diabolical cunning. He is abnormal.

他的忏悔被绝望的虔诚悸动着,但这也不能为他那恶魔的狡诈赎罪，他是变态。

耶鲁公开课 - 1945年后的美国小说课程节选

This is the most common cause of abnormal heartbeat in older adults.

VOA: special.2009.08.12

The goal is to block abnormal electrical activity in the heart.

VOA: special.2010.03.02