EFFECT OF CALCIUM-CHANNEL BLOCK ON THE WALL-MOTION ABNORMALITY OF THE IDIOPATHIC LONG QT SYNDROME
EFFECT OF CALCIUM-CHANNEL BLOCK ON THE WALL-MOTION ABNORMALITY OF THE IDIOPATHIC LONG QT SYNDROME
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DOI：
10.1161/01.cir.89.5.2126
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发表时间：
1994-05-01
期刊：
影响因子：
37.8
通讯作者：
SCHWARTZ, PJ
中科院分区：
文献类型：
--
作者：
DEFERRARI, GM;NADOR, F;SCHWARTZ, PJ
背景 我们最近发现，通过超声心动图评估，特发性长 QT 综合征 (LQTS) 患者经常出现不寻常的心室壁运动异常。开发了两个新的定量指标： Th-1/2（达到最大收缩期增厚一半所需的时间），LQTS 患者的该指标小于对照组； TSTh（快速松弛前处于极低增厚率的时间），在 LQTS 患者中要长得多，表明在增厚后期存在缓慢收缩。这种明显的收缩后期“平台”，无论是直线还是具有特殊的双峰模式，在有晕厥或心脏骤停病史的患者中更为常见。这一令人费解的现象背后的机制仍不清楚。 方法和结果 本研究评估了钙通道阻滞剂维拉帕米对 10 名具有明显平台模式的 LQTS 患者（9 名女性和 1 名男性；平均年龄，19+/-7 岁）和 6 名健康对照者（4 名女性和 2 名男性；平均年龄，28+/-5 岁）收缩模式的影响。在 2 分钟内随机注射维拉帕米 (0.1 mg/kg) 或生理盐水。生理盐水没有效果。在 LQTS 患者中，维拉帕米使 Th-1/2 增加 27%，从心动周期的 16.9+/-3.2% 增加到 21.4+/-3.9% (P=.005)，并使 TSTh 显着降低 92%，从心动周期的 13.7+/-5.3% 增加到 1.08+/-0.6% (P=.005)。
Background We recently showed the frequent occurrence of an unusual ventricular wall motion abnormality, assessed by echocardiography, in patients with the idiopathic long QT syndrome (LQTS). Two new quantitative indexes were developed: Th-1/2 (time needed to reach half of the maximal systolic thickening), which was smaller in LQTS patients than in controls; and TSTh (time spent at a very low thickening rate before rapid relaxation), which was much greater in LQTS patients, indicating the presence of a slow contraction in the late thickening phase. This marked late systolic ''plateau,'' either rectilinear or with a peculiar double peak pattern, was significantly more frequent in patients with a history of syncope or cardiac arrest. The mechanism underlying this puzzling phenomenon remained unexplained.Methods and Results The present study assessed the effects of the calcium channel blocker verapamil on the contraction pattern in 10 LQTS patients (9 females and 1 male; mean age, 19+/-7 years) with a marked plateau pattern and in 6 healthy controls (4 females and 2 males; mean age, 28+/-5 years). Either verapamil (0.1 mg/kg) or saline was randomly injected over 2 minutes. Saline had no effect. In LQTS patients, verapamil increased Th-1/2 by 27%, from 16.9+/-3.2% to 21.4+/-3.9% of the cardiac cycle (P=.005), and dramatically reduced TSTh by 92%, from 13.7+/-5.3% to 1.08+/-0.6% of the cardiac cycle (P