Lambert C R, Coy K, Imperi G, Pepine C J
Department of Medicine, University of Florida, Gainesville.
Am J Cardiol. 1989 Oct 15;64(14):835-9. doi: 10.1016/0002-9149(89)90827-8.
Extended (72-hour) ambulatory electrocardiographic monitoring was used to enable time series analysis of heart rate and asymptomatic ST-segment depression in 9 patients with severe coronary artery disease. The effects of beta 1-adrenergic blockade with optimal dose metoprolol were then assessed. Data were analyzed using Fourier transformation, autocorrelation and cross-correlation to examine possible coupling between heart rate and ischemic electrocardiographic changes. A marked circadian pattern was observed for both heart rate and ambulatory myocardial ischemia, with a period of approximately 24 hours by both Fourier and autocorrelation methods. Cross-correlation revealed heart rate and ischemia to be tightly coupled with a lag of 0 hours during placebo. During beta 1 adrenergic blockade the marked circadian variation in heart rate was diminished, although some periodicity in the 24-hour region remained. Ambulatory ischemia was also markedly diminished during beta 1-adrenergic blockade; however, some residual ischemia remained that was characterized by a peak spectral activity shifted to a period of 5 to 7 hours. Heart rate and ischemia were not coupled during beta 1-adrenergic blockade, as evidenced by lack of significant cross-correlation. Thus, time series analysis suggests close coupling between the variation in heart rate and ambulatory ischemia in patients with severe coronary artery disease. Beta 1-adrenergic blockade can markedly alter the periodic characteristics of and coupling between heart rate and ischemia. Ischemia remaining during beta 1-adrenergic blockade may have different spectral characteristics than that predominating during placebo administration. These differences may be manifestations of the heterogenous pathophysiologic mechanisms responsible for ambulatory ischemia and may have therapeutic implications.
对9例严重冠状动脉疾病患者进行了延长（72小时）的动态心电图监测，以实现心率和无症状ST段压低的时间序列分析。然后评估了使用最佳剂量美托洛尔进行β1肾上腺素能阻滞的效果。使用傅里叶变换、自相关和互相关分析数据，以检查心率与缺血性心电图变化之间可能存在的耦合。通过傅里叶和自相关方法观察到心率和动态心肌缺血均呈现明显的昼夜节律模式，周期约为24小时。互相关分析显示，在服用安慰剂期间，心率与缺血紧密耦合，滞后时间为0小时。在β1肾上腺素能阻滞期间，心率明显的昼夜变化减弱，尽管在24小时范围内仍存在一些周期性。在β1肾上腺素能阻滞期间，动态缺血也明显减少；然而，仍有一些残余缺血，其特征是峰值频谱活动转移到5至7小时的时间段。在β1肾上腺素能阻滞期间，心率与缺血未耦合，这通过缺乏显著的互相关得以证明。因此，时间序列分析表明，严重冠状动脉疾病患者的心率变化与动态缺血之间存在紧密耦合。β1肾上腺素能阻滞可显著改变心率与缺血的周期性特征及两者之间的耦合。β1肾上腺素能阻滞期间残留的缺血可能具有与安慰剂给药期间占主导地位的缺血不同的频谱特征。这些差异可能是导致动态缺血的异质性病理生理机制的表现，并且可能具有治疗意义。
