Next, the ectopic beat could happen during the PR segment, and because the ectopic depolarization happens relatively slowly, oftentimes, it will combine with the normal depolarization wave coming down the ventricular conduction system, resulting in a ventricular fusion beat.

其次，异位心搏可能发生在PR间期，因为异位去极化相对缓慢，它常会和在心室传导系统中下行的正常除极波融合，导致室性融合心搏。