Fujiki Akira, Sugao Masataka, Nishida Kunihiro, Sakabe Masao, Tsuneda Takayuki, Mizumaki Koichi, Inoue Hiroshi
Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Sugitani, Toyama, Japan.
J Cardiovasc Electrophysiol. 2004 Jan;15(1):59-63. doi: 10.1046/j.1540-8167.2004.03396.x.
We evaluated the characteristics of QT-RR and QaT (apex of T wave)-RR relationships in patients with idiopathic ventricular fibrillation (IVF) compared with control subjects. We hypothesized that IVF patients have unique repolarization dynamics related to a reduced fast Na current and a prominent transient outward current.
The study group consisted of 9 men (age 47 +/- 10 years) with IVF (6 with Brugada type and 3 with non-Brugada type) who had experienced nocturnal episodes of VF. The control group consisted of 28 healthy age-matched men (age 44 +/- 12 years). The relationships between QT and RR intervals and between QaT and RR intervals were analyzed from 24-hour Holter ECG data using an automatic measurement system. Both QT and QaT at RR intervals of 0.6, 1.0, and 1.2 seconds were determined from QT-RR and QaT-RR linear regression lines. Both QT-RR and QaT-RR slopes were lower in the IVF group than in the control group (QT-RR: 0.092 +/- 0.023 vs 0.137 +/- 0.031, P < 0.001; QaT-RR: 0.109 +/- 0.025 vs 0.153 +/- 0.028, P < 0.001). QT at an RR interval of 0.6 second did not differ between two groups, but QT at RR intervals of either 1.0 or 1.2 seconds was significantly shorter in the IVF group than in the control group (RR 1.0 s: 0.384 +/- 0.018 vs 0.399 +/- 0.017, P < 0.05; RR 1.2 s: 0.402 +/- 0.019 vs 0.426 +/- 0.020, P < 0.01). QaT at RR intervals of either 1.0 or 1.2 seconds also was shorter in the IVF group (RR 1.0 s: 0.289 +/- 0.022 vs 0.312 +/- 0.021, P < 0.01; RR 1.2 s: 0.311 +/- 0.024 vs 0.343 +/- 0.024, P < 0.01). In four patients, oral administration of disopyramide (300 mg/day) was effective in suppressing VF episodes and increased slopes of QT-RR and QaT-RR relationships.
IVF patients had lower slopes of QT-RR and QaT-RR regression lines and impaired prolongation of QT and QaT at longer RR intervals compared with control subjects. These unique repolarization dynamics may be related to the frequent occurrence of VF episodes at night.
我们评估了特发性室颤（IVF）患者与对照组相比QT-RR和QaT（T波顶点）-RR关系的特征。我们假设IVF患者具有与快速钠电流降低和显著的瞬时外向电流相关的独特复极动力学。
研究组由9名患有IVF的男性（年龄47±10岁）组成（6例为Brugada型，3例为非Brugada型），他们经历过夜发性室颤发作。对照组由28名年龄匹配的健康男性（年龄44±12岁）组成。使用自动测量系统从24小时动态心电图数据中分析QT与RR间期以及QaT与RR间期之间的关系。从QT-RR和QaT-RR线性回归线确定RR间期为0.6、1.0和1.2秒时的QT和QaT。IVF组的QT-RR和QaT-RR斜率均低于对照组（QT-RR：0.092±0.023对0.137±0.031，P<0.001；QaT-RR：0.109±0.025对0.153±0.028，P<0.001）。RR间期为0.6秒时两组的QT无差异，但RR间期为1.0或1.2秒时IVF组的QT显著短于对照组（RR 1.0秒：0.384±0.018对0.399±0.017，P<0.05；RR 1.2秒：0.402±0.019对0.426±0.020，P<0.01）。RR间期为1.0或1.2秒时IVF组的QaT也较短（RR 1.0秒：0.289±0.022对0.312±0.021，P<0.01；RR 1.2秒：0.311±0.024对0.343±0.024，P<0.01）。在4例患者中，口服丙吡胺（300mg/天）可有效抑制室颤发作并增加QT-RR和QaT-RR关系的斜率。
与对照组相比，IVF患者的QT-RR和QaT-RR回归线斜率较低，且在较长RR间期时QT和QaT的延长受损。这些独特的复极动力学可能与夜间室颤发作频繁有关。
