Variability of transient myocardial ischemia in ambulatory patients with coronary artery disease.
Variability of transient myocardial ischemia in ambulatory patients with coronary artery disease.
复制标题
冠状动脉疾病门诊患者短暂性心肌缺血的变异性。
DOI：
10.1161/01.cir.78.1.60
复制
发表时间：
1988
期刊：
影响因子：
37.8
通讯作者：
Selwyn,AP
中科院分区：
文献类型：
--
作者：
Nabel,EG;Barry,J;Rocco,MB;Campbell,S;Mead,K;Fenton,T;Orav,EJ;Selwyn,AP
慢性稳定型心绞痛患者的动态心电图（ECG）监测显示缺血性ST段压低的频繁和长期发作，但其临床应用需要了解变异性的组成和程度。因此，在42例慢性稳定型心绞痛和已知的冠状动脉疾病患者中，通过每日、每周和每月的动态心电图记录来评价ST段压低发作的频率和持续时间的变化。采用嵌套方差分析设计分析数据，得出方差分量的估计值。从方差分量的估计值，功率计算和缺血的频率和持续时间的最小显著百分比降低推导。在4,656小时的动态心电图监测中，检测到1,262次缺血性ST段压低。发作频率为6.3 +/- 0.45/24小时（平均值+/- SEM），发作持续时间为18.3 +/- 2.8/24小时。由于随时间的变化，检测显著变化的能力取决于受试者人数、监测期长度和监测期之间的间隔。例如，在临床试验中，在对照和试验条件之间监测48小时（1周）的25例患者的样本量将需要频率降低65%，而在类似条件下监测50例患者的样本量将需要频率降低46%，以将90%把握度的变化归因于治疗干预而不是自发变化。当对单个患者进行48小时的监测时，在对照和重复监测会话之间间隔1周或1个月，必须消除缺血性ST段压低发作，以在95%置信水平下检测缺血活动的显著治疗变化。（250字处删节）
Ambulatory electrocardiographic (ECG) monitoring of patients with chronic stable angina has demonstrated frequent and prolonged episodes of ischemic ST segment depression, but its clinical use requires an understanding of the components and extent of variability. Therefore, variations in the frequency and duration of episodes of ST segment depression were evaluated with ambulatory ECG recording at daily, weekly, and monthly intervals in 42 patients with chronic stable angina and known coronary artery disease. Data were analyzed with a nested analysis of variance design that yields estimates of variance components. From the estimates of variance components, power calculations and minimum significant percent reductions in frequency and duration of ischemia were derived. During 4,656 hours of ambulatory ECG monitoring, 1,262 episodes of ischemic ST segment depression were detected. The frequency of episodes was 6.3 +/- 0.45/24 hr (mean +/- SEM), and the duration of episodes was 18.3 +/- 2.8/24 hr. Because of variability over time, the ability to detect significant changes was dependent upon the number of subjects, length of monitoring period, and intervals between monitoring periods. In a clinical trial, for example, a sample size of 25 patients monitored for 48 hours with 1 week between control and test conditions would require a 65% reduction in frequency, whereas a sample size of 50 patients monitored under similar conditions would require a 46% reduction in frequency, to attribute the change with 90% power to a therapeutic intervention rather than to a spontaneous variation. When monitoring a single patient for 48 hours with 1 week or 1 month between control and repeat monitoring sessions, episodes of ischemic ST depression must be eliminated to detect significant therapeutic changes in ischemic activity at the 95% confidence level.(ABSTRACT TRUNCATED AT 250 WORDS)