Khan Habib R, Chan William K, Kanawati Juliana, Yee Raymond
London Health Sciences Centre, University of Western Ontario, 339 Windermere Road, London, ON N6A 5A5, Canada.
Eur Heart J Case Rep. 2021 Mar 20;5(3):ytab096. doi: 10.1093/ehjcr/ytab096. eCollection 2021 Mar.
Modern permanent pacemakers (PPMs) have individual features designed to identify cardiac rhythm abnormalities and improve their performance. Inappropriate pacing inhibition may be an undesired outcome from these features and cause symptoms in patients who require frequent pacing, leading to dizziness, and syncope. Inappropriate inhibition can be difficult to identify in circumstances that are intermittent and difficult to reproduce.
A 57-year-old female underwent a mitral valve replacement (MVR) for severe mitral stenosis. One month following MVR, she presented with symptomatic third-degree atrioventricular block, and a dual-chamber PPM (Advisa™, Medtronic, Minneapolis, USA) was implanted and programmed DDD 50-130 b.p.m. At the 3-month follow-up, she reported frequent episodes of lightheadedness. She was found to have intermittent ventricular pacing inhibition on a 48-h Holter monitor due to an internal function of the Advisa™ series of PPMs that attempts to store an electrogram (EGM) every 1 h and 30 s. During the EGM storage, an amplified signal from the storage capacitor can result in oversensing by the ventricular channel and inappropriate pacing inhibition.
To rectify the issue, the ventricular lead sensitivity value was increased from 0.9 mV to 1.2 mV. No instances of inappropriate ventricular pacing inhibition were noted on follow-up. To our knowledge, this is a rare case of inappropriate ventricular pacing inhibition caused by a combination of PPM self-adjusting sensitivity algorithm and oversensing every 1 h and 30 s from an amplified storage capacitor. Physicians should be aware of this possible complication and differentiate it from device or lead malfunction.
现代永久性起搏器（PPM）具有旨在识别心律失常并改善其性能的独特功能。不适当的起搏抑制可能是这些功能产生的不良后果，并在需要频繁起搏的患者中引发症状，导致头晕和晕厥。在间歇性且难以重现的情况下，不适当的抑制可能难以识别。
一名57岁女性因严重二尖瓣狭窄接受二尖瓣置换术（MVR）。MVR术后1个月，她出现有症状的三度房室传导阻滞，并植入了双腔PPM（Advisa™，美敦力公司，美国明尼阿波利斯），并将其程控为DDD模式，心率50 - 130次/分钟。在3个月的随访中，她报告频繁出现头晕。通过48小时动态心电图监测发现，由于Advisa™系列PPM的内部功能，即每1小时30秒尝试存储一次心电图（EGM），导致她出现间歇性心室起搏抑制。在EGM存储期间，来自存储电容器的放大信号可导致心室通道过度感知并产生不适当的起搏抑制。
为纠正该问题，将心室导联灵敏度值从0.9 mV提高到1.2 mV。随访中未发现不适当的心室起搏抑制情况。据我们所知，这是一例罕见的由PPM自我调整灵敏度算法与每1小时30秒来自放大存储电容器的过度感知共同导致的不适当心室起搏抑制病例。医生应意识到这种可能的并发症，并将其与设备或导联故障相区分。
