Jalanko Mikko, Väänänen Heikki, Tarkiainen Mika, Sipola Petri, Jääskeläinen Pertti, Lauerma Kirsi, Laitinen Tiina, Laitinen Tomi, Laine Mika, Heliö Tiina, Kuusisto Johanna, Viitasalo Matti
Department of Cardiology, Heart and Lung Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland.
Ann Noninvasive Electrocardiol. 2018 Nov;23(6):e12582. doi: 10.1111/anec.12582. Epub 2018 Jul 4.
Hypertrophic cardiomyopathy (HCM) is characterized by ventricular repolarization abnormalities and risk of ventricular arrhythmias. Our aim was to study the association between the phenotype and ventricular repolarization dynamics in HCM patients.
HCM patients with either the MYBPC3-Q1061X or TPM1-D175N mutation (n = 46) and control subjects without mutation and hypertrophy (n = 35) were studied with 24-hr ambulatory ECG recordings by measuring time intervals of rate-adapted QT (QTe), maximal QT, and T-wave apex to wave end (TPE) intervals and the QTe/RR slope. Findings were correlated to specified echocardiographic and cardiac magnetic resonance imaging (CMRI) findings.
Rate-adapted QTe interval was progressively longer in HCM patients with decreasing heart rates compared to control subjects (p = 0.020). The degree of hypertrophy correlated with measured QTe values. HCM patients with maximal wall thickness higher than the mean (20.6 mm) had longer maximum QTe and median TPE intervals compared to control subjects and HCM patients with milder hypertrophy (p < 0.001 and p = 0.014, respectively). HCM patients with late gadolinium enhancement (LGE) on CMRI had steeper QTe/RR slopes compared to HCM patients without LGE and control subjects (p = 0.044 and p = 0.001, respectively). LGE was an independent predictor of QTe/RR slope (p = 0.023, B = 0.043).
Dynamics of ventricular repolarization in HCM are affected by hypertrophy and fibrosis. LGE may confer an independent effect on QT dynamics which may increase the arrhythmogenic potential in HCM.
肥厚型心肌病（HCM）的特征是心室复极异常和室性心律失常风险。我们的目的是研究HCM患者的表型与心室复极动力学之间的关联。
对携带MYBPC3 - Q1061X或TPM1 - D175N突变的HCM患者（n = 46）以及无突变和肥厚的对照受试者（n = 35）进行24小时动态心电图记录，测量心率适应性QT（QTe）、最大QT以及T波顶点至波末（TPE）间期的时间间隔和QTe/RR斜率。研究结果与特定的超声心动图和心脏磁共振成像（CMRI）结果相关联。
与对照受试者相比，心率降低时HCM患者的心率适应性QTe间期逐渐延长（p = 0.020）。肥厚程度与测得的QTe值相关。与对照受试者和肥厚程度较轻的HCM患者相比，最大壁厚高于平均值（20.6 mm）的HCM患者的最大QTe和中位TPE间期更长（分别为p < 0.001和p = 0.014）。与无晚期钆增强（LGE）的HCM患者和对照受试者相比，CMRI上有LGE的HCM患者的QTe/RR斜率更陡（分别为p = 0.044和p = 0.001）。LGE是QTe/RR斜率的独立预测因子（p = 0.023，B = 0.043）。
HCM患者的心室复极动力学受肥厚和纤维化影响。LGE可能对QT动力学产生独立影响，这可能增加HCM患者的致心律失常潜力。
