Abstract：
BACKGROUND: Early-onset atrial fibrillation (AF) has already been observed in approximately 2% of patients with genetically proven long QT syndrome (LQTS). This frequency is higher than population-based estimates of early-onset AF. However, the concomitant expression of AF in LQTS is likely underestimated. The purpose of this study was to examine the clinical presentation, genetic background, and outcomes of a cohort of patients with LQTS and early-onset AF referred to a single tertiary center.
METHODS: Twenty-seven patients diagnosed with congenital LQTS were included in the study based on the documentation of early-onset (age ≤50 years) clinical or subclinical AF episodes in all available medical records, including standard electrocardiograms, wearable monitor or cardiac implantable electronic devices.
RESULTS: Seventeen patients experienced clinical AF during the follow-up period. Subclinical AF was detected in 10 patients through insertable or wearable cardiac monitors. In our series, the mean heart rate during AF episodes was found to be relatively low despite the patients\' young age and the low or minimal effective doses of beta-blockers used for QTc interval control. All patients exhibiting LQTS and early-onset AF were genotype positive, carrying mutations in the KCNQ1 (66%), KCNH2, KCNE1, and SCN5A genes. Notably, most of these patients carried the same p.(R231C) mutation in the KCNQ1 gene (59%) and were from the same families, suggesting concurrent expression of familial AF and LQTS.
CONCLUSIONS: LQTS patients are prone to developing clinical and subclinical AF, even at a younger age. The occurrence of early-onset AF in the LQTS population could be more frequent than previously assumed. AF should be considered as a potential dysrhythmia related to LQTS. Our study emphasizes the importance of carefully researching clinical and/or subclinical episodes of AF through strict heart rhythm monitoring in the LQTS population.
METHODS: Twenty-seven patients diagnosed with congenital LQTS were included in the study based on the documentation of early-onset (age ≤50 years) clinical or subclinical AF episodes in all available medical records, including standard electrocardiograms, wearable monitor or cardiac implantable electronic devices.
RESULTS: Seventeen patients experienced clinical AF during the follow-up period. Subclinical AF was detected in 10 patients through insertable or wearable cardiac monitors. In our series, the mean heart rate during AF episodes was found to be relatively low despite the patients\' young age and the low or minimal effective doses of beta-blockers used for QTc interval control. All patients exhibiting LQTS and early-onset AF were genotype positive, carrying mutations in the KCNQ1 (66%), KCNH2, KCNE1, and SCN5A genes. Notably, most of these patients carried the same p.(R231C) mutation in the KCNQ1 gene (59%) and were from the same families, suggesting concurrent expression of familial AF and LQTS.
CONCLUSIONS: LQTS patients are prone to developing clinical and subclinical AF, even at a younger age. The occurrence of early-onset AF in the LQTS population could be more frequent than previously assumed. AF should be considered as a potential dysrhythmia related to LQTS. Our study emphasizes the importance of carefully researching clinical and/or subclinical episodes of AF through strict heart rhythm monitoring in the LQTS population.
摘要：
背景：已经在大约2％的经遗传证实的长QT综合征（LQTS）患者中观察到早发性心房颤动（AF）。该频率高于基于人群的早发性AF估计。然而,房颤在LQTS中的伴随表达可能被低估。这项研究的目的是检查临床表现，遗传背景,LQTS和早发性房颤患者队列的结局转诊至一个三级中心。
方法：根据所有现有医疗记录中的早发性（年龄≤50岁）临床或亚临床房颤发作记录，将27例诊断为先天性LQTS的患者纳入本研究。包括标准心电图,可穿戴监测器或心脏可植入电子设备。
结果：17例患者在随访期间出现临床房颤。通过可插入或可穿戴的心脏监护仪在10名患者中检测到亚临床房颤。在我们的系列中,尽管患者年龄较小,且用于QTc间期控制的β-受体阻滞剂有效剂量较低或最低有效剂量,但房颤发作期间的平均心率相对较低.所有表现为LQTS和早发性房颤的患者均为基因型阳性，在KCNQ1中携带突变（66％），KCNH2、KCNE1和SCN5A基因。值得注意的是,这些患者中的大多数携带相同的p。KCNQ1基因（R231C）突变（59％），并且来自相同的家庭，提示家族性AF和LQTS同时表达。
结论：LQTS患者容易发生临床和亚临床房颤，即使在年轻的时候。LQTS人群中早发性房颤的发生可能比以前假设的更频繁。房颤应被视为与LQTS相关的潜在心律失常。我们的研究强调了在LQTS人群中通过严格的心律监测仔细研究房颤临床和/或亚临床发作的重要性。
方法：根据所有现有医疗记录中的早发性（年龄≤50岁）临床或亚临床房颤发作记录，将27例诊断为先天性LQTS的患者纳入本研究。包括标准心电图,可穿戴监测器或心脏可植入电子设备。
结果：17例患者在随访期间出现临床房颤。通过可插入或可穿戴的心脏监护仪在10名患者中检测到亚临床房颤。在我们的系列中,尽管患者年龄较小,且用于QTc间期控制的β-受体阻滞剂有效剂量较低或最低有效剂量,但房颤发作期间的平均心率相对较低.所有表现为LQTS和早发性房颤的患者均为基因型阳性，在KCNQ1中携带突变（66％），KCNH2、KCNE1和SCN5A基因。值得注意的是,这些患者中的大多数携带相同的p。KCNQ1基因（R231C）突变（59％），并且来自相同的家庭，提示家族性AF和LQTS同时表达。
结论：LQTS患者容易发生临床和亚临床房颤，即使在年轻的时候。LQTS人群中早发性房颤的发生可能比以前假设的更频繁。房颤应被视为与LQTS相关的潜在心律失常。我们的研究强调了在LQTS人群中通过严格的心律监测仔细研究房颤临床和/或亚临床发作的重要性。
