Rieder Marina, Kreifels Paul, Stuplich Judith, Ziupa David, Servatius Helge, Nicolai Luisa, Castiglione Alessandro, Zweier Christiane, Asatryan Babken, Odening Katja E
Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland.
Department of Cardiology and Angiology I, Faculty of Medicine, University Heart Center Freiburg-Bad Krozingen, University of Freiburg, Freiburg, Germany.
Front Cardiovasc Med. 2022 Jul 14;9:916036. doi: 10.3389/fcvm.2022.916036. eCollection 2022.
Congenital long-QT syndrome (LQTS) is a major cause of sudden cardiac death (SCD) in young individuals, calling for sophisticated risk assessment. Risk stratification, however, is challenging as the individual arrhythmic risk varies pronouncedly, even in individuals carrying the same variant.
In this study, we aimed to assess the association of different electrical parameters with the genotype and the symptoms in patients with LQTS. In addition to the heart-rate corrected QT interval (QTc), markers for regional electrical heterogeneity, such as QT dispersion (QT-QT in all ECG leads) and delta T (T V5 - T V2), were assessed in the 12-lead ECG at rest and during exercise testing.
QTc at rest was significantly longer in symptomatic than asymptomatic patients with LQT2 (493.4 ms ± 46.5 ms vs. 419.5 ms ± 28.6 ms, = 0.004), but surprisingly not associated with symptoms in LQT1. In contrast, post-exercise QTc (minute 4 of recovery) was significantly longer in symptomatic than asymptomatic patients with LQT1 (486.5 ms ± 7.0 ms vs. 463.3 ms ± 16.3 ms, = 0.04), while no such difference was observed in patients with LQT2. Enhanced delta T and QT dispersion were only associated with symptoms in LQT1 (delta T 19.0 ms ± 18.1 ms vs. -4.0 ms ± 4.4 ms, = 0.02; QT-dispersion: 54.3 ms ± 10.2 ms vs. 31.4 ms ± 10.4 ms, = 0.01), but not in LQT2. Delta T was particularly discriminative after exercise, where all symptomatic patients with LQT1 had positive and all asymptomatic LQT1 patients had negative values (11.8 ± 7.9 ms vs. -7.5 ± 1.7 ms, = 0.003).
Different electrical parameters can distinguish between symptomatic and asymptomatic patients in different genetic forms of LQTS. While the classical "QTc at rest" was only associated with symptoms in LQT2, post-exercise QTc helped distinguish between symptomatic and asymptomatic patients with LQT1. Enhanced regional electrical heterogeneity was only associated with symptoms in LQT1, but not in LQT2. Our findings indicate that genotype-specific risk stratification approaches based on electrical parameters could help to optimize risk assessment in LQTS.
先天性长QT综合征（LQTS）是年轻人心脏性猝死（SCD）的主要原因，需要进行精细的风险评估。然而，风险分层具有挑战性，因为即使携带相同变异的个体，其心律失常风险也存在显著差异。
在本研究中，我们旨在评估LQTS患者不同电参数与基因型及症状之间的关联。除心率校正QT间期（QTc）外，还在静息及运动试验时的12导联心电图中评估了区域电不均一性标志物，如QT离散度（所有心电图导联中的QT差值）和△T（V5导联T波与V2导联T波差值）。
LQT2有症状患者静息时的QTc显著长于无症状患者（493.4 ms±46.5 ms对419.5 ms±28.6 ms，P = 0.004），但令人惊讶的是，LQT1中QTc与症状无关。相比之下，LQT1有症状患者运动后QTc（恢复第4分钟）显著长于无症状患者（486.5 ms±7.0 ms对463.3 ms±16.3 ms，P = 0.04），而LQT2患者未观察到这种差异。增强的△T和QT离散度仅与LQT1中的症状相关（△T：19.0 ms±18.1 ms对-4.0 ms±4.4 ms，P = 0.02；QT离散度：54.3 ms±10.2 ms对31.4 ms±10.4 ms，P = 0.01），而与LQT2中的症状无关。运动后△T的鉴别能力尤为突出，所有有症状的LQT1患者△T为正值，所有无症状的LQT1患者△T为负值（11.8±7.9 ms对-7.5±1.7 ms，P = 0.003）。
不同电参数可区分不同基因形式LQTS的有症状和无症状患者。经典的“静息QTc”仅与LQT2中的症状相关，运动后QTc有助于区分LQT1的有症状和无症状患者。增强的区域电不均一性仅与LQT1中的症状相关，而与LQT2中的症状无关。我们的研究结果表明，基于电参数的基因型特异性风险分层方法有助于优化LQTS的风险评估。
