Kim Juwon, Oh Il-Young, Cha Myung-Jin, Ahn Jinhee, Lee So-Ryoung, Lee Sung Ho, Uhm Jae-Sun, Yang Pil-Sung, Shim Jaemin, Park Hyoung-Seob, Park Junbeom, Kim Jun Hyung, Kim Ki-Hun, Ko Jumsuk, Lim Hong Euy, Kim Ju Youn
Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Cardiovascular Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
Korean J Intern Med. 2025 Jul;40(4):616-625. doi: 10.3904/kjim.2024.364. Epub 2025 Jul 1.
BACKGROUND/AIMS: Although an implantable loop recorder (ILR) is a valuable tool for investigation of unexplained syncope, there are limited data regarding time course to diagnosis and predictors of serious arrhythmias as a cause of unexplained syncope. We sought to investigate diagnosis rate by time period after ILR implantation and identify predictors of serious arrhythmias in patients with unexplained syncope.
We identified 394 patients who received ILR implantation for unexplained syncope enrolled in the Korean ILR registry.
Serious arrhythmias were documented in 205 patients (52.0%). One hundred seventy-two patients (43.7%) had sick sinus-node syndrome (SSS), 24 (6.1%) had atrioventricular block, and nine (2.3%) had ventricular arrhythmia. Of these, 48 (23.4%) and 77 (37.6%) were diagnosed within two weeks and one month after ILR implantation, respectively. Median time to diagnosis was 62 days. In multivariable analysis, left atrial volume index (LAVI) ≥ 34 mL/m2 (hazard ratio [HR] 1.582), hypertension (HR 1.788), sinus bradycardia with a heartrate less than 60 beats per minute (HR 1.762), and LAVI ≥ 34 mL/m2 combined with sinus bradycardia (HR 1.911) were independent predictors of SSS. Cumulative detection rate of SSS was significantly higher in patients with LAVI ≥ 34 mL/m2 than those with LAVI < 34 mL/m2 (p < 0.001).
More than half of patients with unexplained syncope had serious arrhythmias, and more than one-third of these arrhythmias were diagnosed within one month after ILR implantation. LAVI combined with sinus bradycardia may be a useful predictor of SSS as a cause of unexplained syncope.
背景/目的：尽管植入式循环记录仪（ILR）是用于不明原因晕厥调查的重要工具，但关于诊断的时间进程以及作为不明原因晕厥病因的严重心律失常的预测因素的数据有限。我们旨在研究ILR植入后不同时间段的诊断率，并确定不明原因晕厥患者严重心律失常的预测因素。
我们从韩国ILR登记处中识别出394例因不明原因晕厥接受ILR植入的患者。
205例患者（52.0%）记录到严重心律失常。172例患者（43.7%）患有病态窦房结综合征（SSS），24例（6.1%）患有房室传导阻滞，9例（2.3%）患有室性心律失常。其中，分别有48例（23.4%）和77例（37.6%）在ILR植入后两周内和一个月内被诊断出来。诊断的中位时间为62天。在多变量分析中，左心房容积指数（LAVI）≥34 mL/m²（风险比[HR] 1.582）、高血压（HR 1.788）、心率低于60次/分钟的窦性心动过缓（HR 1.762）以及LAVI≥34 mL/m²合并窦性心动过缓（HR 1.911）是SSS的独立预测因素。LAVI≥34 mL/m²的患者中SSS的累积检出率显著高于LAVI<34 mL/m²的患者（p<0.001）。
超过一半不明原因晕厥患者患有严重心律失常，其中超过三分之一的心律失常在ILR植入后一个月内被诊断出来。LAVI合并窦性心动过缓可能是不明原因晕厥病因中SSS的有用预测因素。
