Abstract：
BACKGROUND: Frequent premature ventricular contractions (PVCs) in children are usually considered benign. Symptoms and left ventricular dysfunction are indications for treatment with antiarrhythmic drugs.
OBJECTIVE: This study aimed to evaluate the efficacy of flecainide vs metoprolol in reducing PVCs in children.
METHODS: A randomized open-label crossover trial was conducted of children with a PVC burden of >15% on Holter monitoring successively treated with metoprolol and flecainide, or vice versa, with a drug-free interval of at least 2 weeks. Holter measurements were repeated before and after the start of the antiarrhythmic drug.
RESULTS: Sixty patients were screened; 19 patients could be included. Median age was 13.9 years (interquartile range, 5.5 years). Mean baseline PVC burden was 21.7% (n = 18; SD ± 14.0) before the start of flecainide and 21.2% (n = 17; SD ± 11.5) before the start of metoprolol. In a mixed model analysis, the estimated mean reduction in PVC burden was 10.6 percentage points (95% CI, 5.8-15.3) for flecainide and 2.4 percentage points (95% CI,2.7-7.5) for metoprolol, with a significant difference of 8.2 percentage points (95% CI, 0.86-15.46; P = .031). Exploratory analysis revealed that 9 of 18 patients treated with flecainide and 1 of 17 patients treated with metoprolol had a reduction to a PVC burden below 5%. No discriminating factors between flecainide responders and nonresponders were found; the mean plasma level was not significantly different (0.34 mg/L vs 0.52 mg/L; P = .277).
CONCLUSIONS: In children with frequent PVCs, flecainide led to a significantly greater reduction of PVC burden compared with metoprolol. Flecainide was effective in only a subgroup of patients, which appears to be unrelated to the plasma level.
OBJECTIVE: This study aimed to evaluate the efficacy of flecainide vs metoprolol in reducing PVCs in children.
METHODS: A randomized open-label crossover trial was conducted of children with a PVC burden of >15% on Holter monitoring successively treated with metoprolol and flecainide, or vice versa, with a drug-free interval of at least 2 weeks. Holter measurements were repeated before and after the start of the antiarrhythmic drug.
RESULTS: Sixty patients were screened; 19 patients could be included. Median age was 13.9 years (interquartile range, 5.5 years). Mean baseline PVC burden was 21.7% (n = 18; SD ± 14.0) before the start of flecainide and 21.2% (n = 17; SD ± 11.5) before the start of metoprolol. In a mixed model analysis, the estimated mean reduction in PVC burden was 10.6 percentage points (95% CI, 5.8-15.3) for flecainide and 2.4 percentage points (95% CI,2.7-7.5) for metoprolol, with a significant difference of 8.2 percentage points (95% CI, 0.86-15.46; P = .031). Exploratory analysis revealed that 9 of 18 patients treated with flecainide and 1 of 17 patients treated with metoprolol had a reduction to a PVC burden below 5%. No discriminating factors between flecainide responders and nonresponders were found; the mean plasma level was not significantly different (0.34 mg/L vs 0.52 mg/L; P = .277).
CONCLUSIONS: In children with frequent PVCs, flecainide led to a significantly greater reduction of PVC burden compared with metoprolol. Flecainide was effective in only a subgroup of patients, which appears to be unrelated to the plasma level.
摘要：
背景：儿童中频繁的室性早搏（PVC）通常被认为是良性的。症状和/或左心室功能障碍是使用抗心律失常药物（AAD）治疗的适应症。
目的：评价氟卡尼与美托洛尔在减少儿童PVCs方面的疗效。
方法：一项随机开放标签交叉试验，儿童在Holter上的PVC负担>15％；连续接受美托洛尔和氟卡尼治疗，反之亦然，至少两周的无药物间隔。在AAD开始之前和之后重复Holter测量。
结果：筛选了60例患者，可纳入19名患者。中位年龄为13.9岁（IQR5.5岁）。在开始使用氟卡尼之前，平均基线PVC负荷为21.7％（N=18，SD±14.0），在开始使用美托洛尔之前为21.2％（N=17，SD±11.5）。在混合模型分析中，氟卡尼的PVC负荷估计平均降低为10.6个百分点（95％-CI5.8-15.3），美托洛尔为2.4个百分点（95％-CI-2.7-7.5）。差异有8.2个百分点(95%-CI为0.86-15.46,P=0.031)。探索性分析显示，9/18患者接受氟卡尼治疗，1/17患者接受美托洛尔治疗，PVC负荷降低到5%以下。没有发现氟卡尼应答者和非应答者之间的区别因素；平均血浆水平没有显着差异（0.34mg/L与0.52mg/L，P=0.277）。
结论：在患有频繁PVC的儿童中，氟卡尼导致PVC负担显着降低，与美托洛尔相比.氟卡尼仅对患者亚组有效，这似乎与血浆水平无关。（荷兰审判登记号26689）。
目的：评价氟卡尼与美托洛尔在减少儿童PVCs方面的疗效。
方法：一项随机开放标签交叉试验，儿童在Holter上的PVC负担>15％；连续接受美托洛尔和氟卡尼治疗，反之亦然，至少两周的无药物间隔。在AAD开始之前和之后重复Holter测量。
结果：筛选了60例患者，可纳入19名患者。中位年龄为13.9岁（IQR5.5岁）。在开始使用氟卡尼之前，平均基线PVC负荷为21.7％（N=18，SD±14.0），在开始使用美托洛尔之前为21.2％（N=17，SD±11.5）。在混合模型分析中，氟卡尼的PVC负荷估计平均降低为10.6个百分点（95％-CI5.8-15.3），美托洛尔为2.4个百分点（95％-CI-2.7-7.5）。差异有8.2个百分点(95%-CI为0.86-15.46,P=0.031)。探索性分析显示，9/18患者接受氟卡尼治疗，1/17患者接受美托洛尔治疗，PVC负荷降低到5%以下。没有发现氟卡尼应答者和非应答者之间的区别因素；平均血浆水平没有显着差异（0.34mg/L与0.52mg/L，P=0.277）。
结论：在患有频繁PVC的儿童中，氟卡尼导致PVC负担显着降低，与美托洛尔相比.氟卡尼仅对患者亚组有效，这似乎与血浆水平无关。（荷兰审判登记号26689）。
