α1-交感神经活动对稳定型心绞痛患者缺血阈值日间变化的重要性。

Importance of alpha 1-sympathetic activity for diurnal change in ischemic threshold in patients with stable angina.

作者信息

Fujita M, Tanaka T, Nakae I, Tamaki S, Kihara Y, Nohara R, Sasayama S

机构信息

College of Medical Technology, Kyoto University, Graduate School of Medicine, Japan.

出版信息

Clin Cardiol. 1998 May;21(5):357-61. doi: 10.1002/clc.4960210512.

DOI:10.1002/clc.4960210512

PMID:9595220

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC6656048/

Abstract

BACKGROUND

Although ischemic threshold reportedly is lower in the early morning than in the afternoon, the mechanisms that account for the diurnal change in minimal coronary vascular resistance in the potentially ischemic area are unknown.

HYPOTHESIS

We hypothesized that calcium-channel blockers and alpha 1 blockers may affect the ischemic threshold in the early morning and afternoon in patients with stable angina.

METHODS

Before and after the administration of the calcium antagonist amlodipine (5 mg) alone and combined with the alpha 1 blocker prazosin (1 mg), a treadmill exercise test using the Balke-Ware protocol was undertaken in the morning (8:00 A.M.) and repeated in the afternoon (1:00 P.M.) with 15 stable angina patients. The ischemic threshold was defined as a reciprocal of minimal coronary vascular resistance in the presence of comparable levels of myocardial ischemia indicated by 0.1 mV ST depression. Minimal coronary vascular resistance was calculated as mean blood pressure divided by coronary blood flow. Since the coronary blood flow is closely related to myocardial oxygen consumption, which can be replaced by the double product of heart rate and systolic blood pressure, minimal coronary vascular resistance was approximated to 1/heart rate.

RESULTS

At baseline, minimal coronary vascular resistance was significantly higher in the early morning than in the afternoon (8.5 +/- 0.3 x 10(-3) min/beats vs. 7.8 +/- 0.4 x 10(-3) min/beats, p < 0.01). Although treatment with amlodipine alone did not abolish the circadian pattern of minimal coronary vascular resistance (8.0 +/- 0.6 x 10(-3) min/beats vs. 7.7 +/- 0.6 x 10(-3) min/ beats, p < 0.05), the addition of prazosin virtually eliminated the diurnal difference in minimal coronary vascular resistance (7.4 +/- 0.5 x 10(-3) min/beats vs. 7.5 +/- 0.5 x 10(-3) min/beats, p = NS).

CONCLUSIONS

These findings indicate that alpha 1-sympathetic activity may play a role in the pathogenesis of the diurnal change of ischemic threshold in patients with stable angina.

摘要

背景

尽管据报道清晨的缺血阈值低于下午，但潜在缺血区域最小冠状动脉血管阻力昼夜变化的机制尚不清楚。

假设

我们假设钙通道阻滞剂和α1受体阻滞剂可能会影响稳定型心绞痛患者清晨和下午的缺血阈值。

方法

对15例稳定型心绞痛患者在早晨（上午8:00）单独服用钙拮抗剂氨氯地平（5毫克）以及联合服用α1受体阻滞剂哌唑嗪（1毫克）前后，采用Balke-Ware方案进行平板运动试验，并于下午（下午1:00）重复进行。缺血阈值定义为在出现0.1 mV ST段压低所指示的可比程度心肌缺血时最小冠状动脉血管阻力的倒数。最小冠状动脉血管阻力计算为平均血压除以冠状动脉血流量。由于冠状动脉血流量与心肌耗氧量密切相关，而心肌耗氧量可用心率与收缩压的乘积来替代，因此最小冠状动脉血管阻力近似为1/心率。

结果

在基线时，清晨的最小冠状动脉血管阻力显著高于下午（8.5±0.3×10⁻³分钟/搏动 vs. 7.8±0.4×10⁻³分钟/搏动，p<0.01）。尽管单独使用氨氯地平治疗并未消除最小冠状动脉血管阻力的昼夜模式（8.0±0.6×10⁻³分钟/搏动 vs. 7.7±0.6×10⁻³分钟/搏动，p<0.05），但添加哌唑嗪实际上消除了最小冠状动脉血管阻力的昼夜差异（7.4±0.5×10⁻³分钟/搏动 vs. 7.5±0.5×10⁻³分钟/搏动，p=无显著差异）。