DOI: 10.1161/circ.148.suppl_1.13558 ISSN: 0009-7322

Abstract 13558: Age-Dependent Change of Electrocardiographic Characteristics and Cardiac Events in the Long QT Syndrome Type-3 With E1784K Mutation of SCN5A

Hiroyuki Kamada, Keiko Shimamoto, Yuichiro Miyazaki, Akinori Wakamiya, Nobuhiko Ueda, Kenzaburo Nakajima, Tsukasa Kamakura, Mitsuru Wada, kohei ishibashi, Yuko Inoue, Koji Miyamoto, Satoshi Nagase, Yoshiaki Kato, Heima Sakaguchi, Yoshihiro Asano, Kazuhiro Takahashi, Wataru Shimizu, Mitsuru Ohishi, Kengo Kusano, Takeshi Aiba
  • Physiology (medical)
  • Cardiology and Cardiovascular Medicine

Introduction: The pathogenic variant of E1784K in SCN5A is known as an overlapped phenotype; long-QT syndrome type-3 (LQT3) and Brugada syndrome (BrS), however it is still unclear age-dependent changes of the ECG findings and which ECG parameters are associated with cardiac events (CEs) in LQT3 patients with SCN5A -E1784K.

Methods: Total 79 LQT3 patients with SCN5A -E1784K (45 probands, 42 males, age 23±17 years, QTc interval: 500±33 ms) were enrolled from the NCVC LQTS registry (2003~2023). We retrospectively evaluated age-dependent change of the clinical characteristics, ECG parameters and those associated with CEs.

Results: Overall, 14 (18%) patients had CEs (10 syncope and 4 ventricular fibrillation), in which 8 occurred under 25 years old, but 6 occurred more than 35 years old. Thus, we divided all into two groups: younger (n=51) or older (n=28) than 30 years old. The younger group shows higher prevalence of male and proband compared with older group, and half of the syncope occurred during exercise. In the ECG parameters, P-R interval and QRS width were significantly longer in older group, in contrast, presence of T-wave alternance, notched, biphasic T-wave and bradycardia were more prevalent in younger group although the QTc interval and QTc peak-end were not different between the two group. Univariate analysis for CEs shows that longer QTc peak-end interval and absence of family history of LQTS are associated with CEs in younger group, whereas in older group, not only the longer QTc peak-end interval and absence of family history but also the Brugada ECG were associated with CEs. Finally, multivariate logistic regression analysis for all patients revealed that longer P-R interval, QTc peak-end and absence of family history of LQTS were independently associated with CEs (p=0.049, p<0.001, p=0.001, respectively). ROC analysis revealed that P-R interval ≥180 ms and QTc peak-end interval ≥86 ms were significantly related to previous CEs.

Conclusion: In LQT3 with SCN5A -E1784K variant, ECG parameters were age-dependently altered and longer P-R and QTc peak-end interval as well as absence of family history of LQTS can be associated with CEs. Furthermore, in adult patients, more careful follow-up should be required for those with LQT3 overlapped with BrS ECG.

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