Fujito T, Takayanagi K, Shimizu M, Inoue T, Hayashi T, Sakai Y, Morooka S, Takabatake Y
Department of Cardiology, Koshigaya Hospital, Dokkyo University School of Medicine, Saitama, Japan.
Jpn Heart J. 1994 Mar;35(2):125-40. doi: 10.1536/ihj.35.125.
To determine the number of days required to obtain 75% suppression of ventricular premature contractions (VPCs) by antiarrhythmic agents, which was expressed as t1/4, we performed 32 in-hospital continuous all day ECG monitoring trials in four groups of 28 symptomatic patients (ages; 54 +/- 20 years-old) with frequent VPCs. Nine patients had no organic heart disease (group 1, 11 trials), nine had valvular heart disease (group 2, 10 trials), three had dilated cardiomyopathy (group 3, 3 trials) and seven had myocardial infarction within two to four weeks onset (group 4, 8 trials). All patients were monitored by ECG telemetry with an arrhythmia analyzer, which could count hourly and daily VPCs. Class I antiarrhythmic agents were given in 18 trials, class II in two trials and class I+ class II in 12 trials. Plasma concentrations of the antiarrhythmic agents were monitored in 11 trials. In 21 trials, t1/4 could be obtained; ten (91%), six (60%), three (100%) and two trials (25%) in the four groups, respectively (p < 0.05). The value of t1/4 in the four groups was 6 +/- 6, 7 +/- 6, 14 +/- 11 and 13 +/- 2 days, respectively (mean 8 +/- 7 days; N.S.). Immediate response to the initial antiarrhythmic agent administration, expressed as percent VPC count after three hours, correlated significantly with t1/4 (r = 0.696, p = 0.0006), but ejection fraction, patient's age, control VPC counts or plasma antiarrhythmic agent level did not correlate with t1/4. In conclusion, t1/4 is a useful index for the evaluation of VPC suppression, revealing wide inter-individual variations and can be roughly estimated from the immediate response to the initial antiarrhythmic agent administration.
为确定抗心律失常药物使室性早搏（VPC）抑制75%所需的天数（表示为t1/4），我们对四组共28例有症状的频发VPC患者（年龄54±20岁）进行了32次住院全天连续心电图监测试验。9例患者无器质性心脏病（第1组，11次试验），9例有瓣膜性心脏病（第2组，10次试验），3例有扩张型心肌病（第3组，3次试验），7例在发病后两至四周内发生心肌梗死（第4组，8次试验）。所有患者均通过带有心律失常分析仪的心电图遥测进行监测，该分析仪可每小时和每天计数VPC。18次试验给予I类抗心律失常药物，2次试验给予II类，12次试验给予I类+II类。11次试验监测了抗心律失常药物的血浆浓度。21次试验可获得t1/4；四组分别为10次（91%）、6次（60%）、3次（100%）和2次试验（25%）（p<0.05）。四组的t1/4值分别为6±6、7±6、14±11和13±2天（平均8±7天；无显著性差异）。初始抗心律失常药物给药后的即时反应，以三小时后的VPC计数百分比表示，与t1/4显著相关（r = 0.696，p = 0.0006），但射血分数、患者年龄、对照VPC计数或血浆抗心律失常药物水平与t1/4均无相关性。总之，t1/4是评估VPC抑制的有用指标，显示出个体间差异很大，并且可以根据对抗心律失常药物初始给药的即时反应大致估算出来。
