Department of Cardiology, Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
Department of Cardiology, Shaare Zedek Medical Center, Jerusalem, Israel.
Europace. 2018 Feb 1;20(2):370-376. doi: 10.1093/europace/euw439.
Type 3 long QT syndrome (LQT3) is caused by gain-of-function mutations in the cardiac sodium channel gene (SCN5A). Previous reports on the long-term use of sodium channel blockers in LQT3 are sparse. The objective of the current study was to evaluate the long-term safety and efficacy of flecainide therapy in patients with LQT3 who carry the D1790G SCN5A mutation.
The study population comprised 30 D1790G carriers who were treated with flecainide and followed for 1-215 months (mean 145 ± 54 months, median 140 months). The mean baseline (off-drug) QTc was 522 ± 45 ms, and shortened to 469 ± 36 ms with flecainide therapy, a mean decrease of 53 ms [10.1%] (P < 0.01). A QTc longer than 500 ms was evident in 53% of carriers at baseline, and only in 13% on flecainide. All carriers while being compliant with flecainide therapy had no cardiac events during an average follow up of 83 ± 73 months. Twenty carriers stopped flecainide after an average follow up of 40 ± 42 months without symptoms. Six of them (30%) had cardiac events 1-11 months after stopping flecainide. Flecainide induced the appearance of Brugada pattern in six carriers (20%, 5 males), was stopped in three and was not associated with arrhythmia. Sinus-node dysfunction was evident in six carriers (20%) and was fully corrected by flecainide in three.
These data suggest that long-term flecainide therapy is relatively safe and effective among LQT3 patients who carry the D1790G SCN5A mutation.
3 型长 QT 综合征（LQT3）是由心脏钠离子通道基因（SCN5A）的功能获得性突变引起的。先前关于 LQT3 中钠离子通道阻滞剂长期使用的报告很少。本研究的目的是评估携带 D1790G SCN5A 突变的 LQT3 患者长期使用氟卡尼治疗的安全性和疗效。
研究人群包括 30 名接受氟卡尼治疗并随访 1-215 个月（平均 145±54 个月，中位数 140 个月）的 D1790G 携带者。平均基线（停药）QTc 为 522±45ms，氟卡尼治疗后缩短至 469±36ms，平均降低 53ms[10.1%]（P<0.01）。基线时 53%的携带者 QTc 大于 500ms，而服用氟卡尼后仅 13%的携带者 QTc 大于 500ms。所有在氟卡尼治疗期间依从性良好的携带者在平均 83±73 个月的随访中均无心脏事件。20 名携带者在平均 40±42 个月的随访后停止服用氟卡尼，无任何症状。其中 6 名（30%）在停止氟卡尼后 1-11 个月出现心脏事件。氟卡尼在 6 名携带者（20%，5 名男性）中诱发 Brugada 图形，在 3 名携带者中停止使用，与心律失常无关。窦房结功能障碍在 6 名携带者（20%）中明显，并在 3 名携带者中被氟卡尼完全纠正。
这些数据表明，在携带 D1790G SCN5A 突变的 LQT3 患者中，长期使用氟卡尼治疗相对安全有效。
