Division of Cardiology, Department of Medicine, University of Ottawa Heart Institute, Ottawa, Ontario, Canada.
J Am Coll Cardiol. 2013 Nov 5;62(19):1772-9. doi: 10.1016/j.jacc.2013.04.084. Epub 2013 Jun 27.
The aim of this study was to determine if exercise testing could expose a latent electrical substrate of arrhythmogenic right ventricular cardiomyopathy (ARVC) in asymptomatic gene carriers.
Management of asymptomatic ARVC gene carriers is challenging because of variable penetrance of disease and the recognition that sudden cardiac death may be the first clinical manifestation.
Exercise-induced abnormalities during exercise treadmill testing (ETT) were initially compared in 60 subjects: 30 asymptomatic ARVC gene carriers and 30 healthy controls. In phase 2 of the study, ETT results of 25 patients with ARVC with histories of sustained ventricular arrhythmia or cardiac arrest were evaluated to determine if ETT abnormalities in asymptomatic gene carriers were common to patients with a malignant electrical form of the disease.
Depolarization abnormalities during ETT were found to develop more frequently in asymptomatic gene carriers compared with healthy controls: epsilon waves appeared in 4 of 28 (14%) compared with 0 of 30 (0%) (p = 0.048), premature ventricular contractions in 17 of 30 (57%) compared with 3 of 30 (10%) (p = 0.0003), and new QRS terminal activation duration ≥ 55 ms in 7 of 22 (32%) compared with 2 of 29 (7%) (p = 0.03). Superior axis premature ventricular contractions occurred only in gene carriers. In the second phase of the study, the frequency of these abnormalities was found to be high in patients with symptomatic ARVC: new epsilon waves appeared in 3 of 18 (17%), superior axis premature ventricular contractions in 21 of 25 (84%), and new terminal activation duration ≥ 55 ms in 8 of 12 (67%).
Exercise testing exposes a latent electrical substrate in asymptomatic ARVC gene carriers that is shared by patients with ARVC with histories of ventricular arrhythmia. ETT may be useful in guiding treatment decisions, exercise prescription, and prioritizing medical surveillance in asymptomatic ARVC gene carriers.
本研究旨在确定运动试验是否能在无症状 ARVC 基因携带者中发现心律失常性右心室心肌病（ARVC）的潜在电基质。
由于疾病的可变外显率以及认识到心脏性猝死可能是首次临床表现，因此对无症状 ARVC 基因携带者的管理具有挑战性。
在 60 名受试者中比较了运动平板试验（ETT）期间的运动诱导异常：30 名无症状 ARVC 基因携带者和 30 名健康对照者。在研究的第二阶段，评估了 25 例有持续性室性心律失常或心脏骤停病史的 ARVC 患者的 ETT 结果，以确定无症状基因携带者的 ETT 异常是否与具有恶性电形式的疾病患者常见。
与健康对照组相比，在无症状基因携带者中发现 ETT 期间出现去极化异常更为频繁：出现 ε 波的比例为 4/28（14%），而 0/30（0%）（p=0.048），出现室性期前收缩的比例为 17/30（57%），而 3/30（10%）（p=0.0003），新 QRS 终末激活持续时间≥55ms 的比例为 7/22（32%），而 2/29（7%）（p=0.03）。优势轴室性期前收缩仅见于基因携带者。在研究的第二阶段，发现这些异常在有症状 ARVC 患者中的频率较高：新出现 ε 波的比例为 3/18（17%），出现优势轴室性期前收缩的比例为 21/25（84%），新出现的终末激活持续时间≥55ms 的比例为 8/12（67%）。
运动试验在无症状 ARVC 基因携带者中暴露了一种潜在的电基质，这种基质与有室性心律失常病史的 ARVC 患者共享。ETT 可能有助于指导治疗决策、运动处方以及在无症状 ARVC 基因携带者中进行医疗监测。
