Kandori Akihiko, Shimizu Wataru, Yokokawa Miki, Maruo Takeshi, Kanzaki Hideaki, Nakatani Satoshi, Kamakura Shiro, Miyatake Kunio, Murakami Masahiro, Miyashita Tsuyoshi, Ogata Kuniomi, Tsukada Keiji
Central Research Laboratory, Hitachi Ltd, 1-280 Higashi-Koigakubo, Kokubunji, Tokyo 185-8601, Japan.
Physiol Meas. 2002 Nov;23(4):603-14. doi: 10.1088/0967-3334/23/4/301.
The aim of this study is to detect the spatial current dispersion that appears in the T-wave of patients with congenital long-QT syndrome (LQTS). To observe this dispersion, magnetocardiograms (MCGs)--which have a high spatial resolution--of LQT1 patients (n = 7), LQT2 patients (n = 9) and a control group (n = 33) were recorded. The dispersion was evaluated by plotting current-arrow maps (CAMs) calculated from the MCG signals. In the case of LQT1, abnormal current arrows in the CAMs appeared above the inferior part of the heart in two LQT1 patients with a long corrected QT interval (QTc) (>0.6), and the current direction was from the left (origin side) to the right ventricular muscle (110 degrees). In six out of nine LQT2 patients, abnormal current arrows with angles below 20 degrees were observed above the right inferior part or lower septum; the current direction was from the right (origin side) to the left ventricular muscle. However, in the case of the LQT2 patients, the QTc values did not correlate with the abnormal current. These findings suggest that the origin of abnormal repolarization in LQT1 is the left ventricular muscle and the origin of that in LQT2 is the right ventricular muscle or lower septum. The estimation of the origin in LQTS patients can provide important information such as the risk factor of sudden death.
本研究的目的是检测先天性长QT综合征（LQTS）患者T波中出现的空间电流离散情况。为观察这种离散情况，记录了LQT1患者（n = 7）、LQT2患者（n = 9）和对照组（n = 33）的高空间分辨率心磁图（MCG）。通过绘制根据MCG信号计算得出的电流箭头图（CAM）来评估离散情况。在LQT1患者中，两名校正QT间期（QTc）较长（>0.6）的LQT1患者的CAM中，异常电流箭头出现在心脏下部上方，电流方向是从左侧（起始侧）指向右心室肌（110度）。在9名LQT2患者中的6名患者中，在右下部分或下间隔上方观察到角度低于20度的异常电流箭头；电流方向是从右侧（起始侧）指向左心室肌。然而，对于LQT2患者，QTc值与异常电流并无关联。这些发现表明，LQT1中异常复极化的起源是左心室肌，而LQT2中异常复极化的起源是右心室肌或下间隔。对LQTS患者起源的估计可为诸如猝死风险因素等重要信息提供依据。
