Lande G, Funck-Brentano C, Ghadanfar M, Escande D
Laboratoire des Explorations Fonctionnelles, Centre Hospitalier Universitaire, Nantes, France.
Pacing Clin Electrophysiol. 2000 Mar;23(3):293-302. doi: 10.1111/j.1540-8159.2000.tb06752.x.
The aim of the present study was to investigate the QT-RR interval relationship in ambulatory ECG recordings with special emphasis on the physiological circumstances under which the QT-RR intervals follow a linear relation. Continuous ECG recordings make it possible to automatically measure QT duration in individual subjects under various physiological circumstances. However, identification of QT prolongation in Holter recordings is hampered by the rate dependence of QT duration. Comparison of QT duration and QT interval rate dependence between different individuals implies that the nature of the QT-RR relationship is defined in ambulatory ECG. Holter recordings were performed in healthy volunteers at baseline and after administration of dofetilide, a Class III antiarrhythmic drug. After dofetilide, beat-to-beat automated QT measurements on Holter tapes were compared with manually measured QT intervals on standard ECGs matched by time. The QT-RR relationship was analyzed at baseline in individual and group data during three different periods: 24-hour, daytime, and nighttime. Data were collected under steady-state or non-steady-state conditions of cycle length and fitted with various correction formulae. Our study demonstrated an excellent agreement between manually and automated measurements. The classic Bazett correction formula did not fit the QT-RR data points in individual or group data. When heart beats were selected for a steady rhythm during the preceding minute, QT-RR intervals fit a linear relationship during the day and night periods, but not during the 24-hour period in both individual and group data. In contrast, in the absence of beat selection, data fit a more complex curvilinear relationship irrespective of the period. Our study provides the basis for comparison of QT interval durations and QT-RR relationships between individuals and between groups of subjects.
本研究的目的是调查动态心电图记录中的QT-RR间期关系，特别强调QT-RR间期呈线性关系的生理情况。连续心电图记录使在各种生理情况下自动测量个体的QT间期成为可能。然而，动态心电图记录中QT间期延长的识别受到QT间期心率依赖性的阻碍。不同个体之间QT间期和QT间期心率依赖性的比较意味着QT-RR关系的本质在动态心电图中是确定的。在健康志愿者基线时以及给予III类抗心律失常药物多非利特后进行动态心电图记录。给予多非利特后，将动态心电图磁带逐搏自动测量的QT间期与按时间匹配的标准心电图上手动测量的QT间期进行比较。在个体和组数据的基线时，在三个不同时间段分析QT-RR关系：24小时、白天和夜间。在周期长度的稳态或非稳态条件下收集数据，并拟合各种校正公式。我们的研究表明手动测量和自动测量之间具有良好的一致性。经典的Bazett校正公式不适合个体或组数据中的QT-RR数据点。当在前一分钟选择心律稳定的心跳时，在白天和夜间时段，QT-RR间期符合线性关系，但在个体和组数据的24小时时段则不然。相比之下，在不进行心跳选择的情况下，无论时间段如何，数据都符合更复杂的曲线关系。我们的研究为个体之间以及受试者组之间QT间期持续时间和QT-RR关系的比较提供了基础。
