Quintal R E, Dhurandhar R W, Jain R K
Pacing Clin Electrophysiol. 1987 Mar;10(2):378-81. doi: 10.1111/j.1540-8159.1987.tb05976.x.
We describe pacemaker pauses and pseudohysteresis resulting from sensing of retrograde P waves in a patient with an implanted AV sequential universal pacemaker. Although retrograde P waves are usually followed by a ventricular spike and therefore create the possibility for "endless loop tachycardia," in our patient some retrograde P waves which followed premature ventricular contractions or junctional beats produced pacemaker pauses. The reason for the occurrence of this phenomenon is that the sum of the VA conduction time and the AV delay is shorter than the pacemaker's hardware rate limit. Therefore, the ventricular spike that should follow the retrograde P wave is inhibited. In the pacemaker used by us, the atrial refractory period is only initiated by an atrial event, allowing the pacemaker to sense retrograde P waves occurring after premature junctional or ventricular depolarizations. Although no therapy is needed for the phenomenon described, it is important to understand its true significance and to avoid unnecessary surgical procedures.
我们描述了一名植入房室顺序通用起搏器患者因感知逆行P波而导致的起搏器停顿和假性滞后现象。尽管逆行P波之后通常会跟随一个心室起搏信号，因此有可能引发“无休止环形心动过速”，但在我们的患者中，一些跟随室性早搏或交界性搏动出现的逆行P波却导致了起搏器停顿。出现这种现象的原因是室房传导时间与房室延迟之和短于起搏器的硬件频率限制。因此，本应跟随逆行P波出现的心室起搏信号被抑制。在我们使用的起搏器中，心房不应期仅由心房事件启动，这使得起搏器能够感知在交界性或室性过早去极化之后出现的逆行P波。尽管对于所描述的这种现象无需进行治疗，但了解其真正意义并避免不必要的外科手术很重要。
