背景:无环心动过速(ELT)是在使用心脏可植入电子设备(CIED)的患者中遇到的最常见的起搏器介导的心动过速(PMT)。尽管启用了各种预防算法,我们遇到了几个反复发作的病例,长,和症状ELT。
方法:我们回顾性分析了2019年1月至2023年3月在印度东部单个中心的设备诊所进行的连续设备检查。
结果:4520例器械检查中有20例确诊和持续ELT。虽然大部分是良性的,在两种情况下,ELT导致左心室(LV)收缩功能障碍患者的临床恶化。即使心室功能良好,ELT导致房室(AV)同步性不当,导致一例出现致残症状。ELT与窦性心动过速和房性心动过速(AT)的区别并不总是容易的。磁体应用肯定是有用的区分。在这项研究中引发ELT的情况是长时间的AV延迟,VIP(心室内在偏好)/MVP(心室管理起搏),心房非捕获,心房欠/过感,室性早搏(PVC)/对联,心房过早收缩(PAC)和心室心房(VA)传导较慢。心室后心房不应期(PVARP)的速率响应缩短也促进了其发生并阻碍了故障排除。当发生ELT时,尽管PVARP的PVC后扩展,降低心房的敏感性,在测量VA传导时间后切换到双极传感和手动设置更长的PVARP是有用的。在某些情况下,必须关闭“速率响应PVARP”以防止ELT。相反,PVARP过度扩张导致2例患者出现重复的非折返性心室心房同步性(RNRVAS).检查植入过程中的VA传导和随访过程中的无创程序刺激(NIPS)可用于检查ELT的趋势。
结论:临床显著的ELT是罕见的,但在具有内置预防算法的设备中并不少见。手动调整通常对排除故障很有用。
BACKGROUND: Endless loop tachycardia (ELT) is the commonest pacemaker mediated tachycardia (PMT) encountered among patients with cardiac implantable electronic
devices (CIEDs). Despite being enabled with various preventive algorithms, we encountered several cases having recurrent, long, and symptomatic ELT.
METHODS: We retrospectively analyzed consecutive device checkups at device clinic at a single center of eastern India between January 2019 to March 2023.
RESULTS: There were 20 cases of confirmed and sustained ELT among 4520 device checks. Although mostly benign, in two cases ELT led to clinical worsening in patients having left ventricular (LV) systolic dysfunction. Even with good ventricular function, ELT resulted in improper atrioventricular (AV) synchrony leading to disabling symptom in one
case. The differentiation of ELT from sinus tachycardia and atrial tachycardia (AT) was not always easy. Magnet application is certainly useful to differentiate. The situations that provoked ELT in this study were-long AV delays, VIP (ventricular intrinsic preferences)/MVP (managed ventricular pacing), atrial non-capture, atrial under/over sensing, premature ventricular contractions (PVCs)/couplets, premature atrial contractions (PAC) and slower ventriculo-atrial (VA) conduction. Rate responsive shortening of post-ventricular atrial refractory period (PVARP) also promoted its occurrence and hindered troubleshooting. When ELT occurred despite post-PVC extension of PVARP, lowering the atrial sensitivity, switching to bipolar sensing and manual setting of longer PVARP after measuring VA conduction time were useful. \"Rate responsive PVARP\" had to be turned off in a few cases to prevent ELT. On the contrary, an over aggressive prolongation of PVARP led to repetitive non-reentrant ventriculo-atrial synchrony (RNRVAS) in two cases. Checking VA conduction during implantation and noninvasive program stimulation (NIPS) during follow up were useful to check the tendency for ELT.
CONCLUSIONS: Clinically significant ELT is rare but not uncommon among
devices having in-built preventive algorithms. Manual adjustments are often useful to troubleshoot the same.