Scrutinio D, Lagioia R, Di Biase M, Rizzon P
Clinica del Lavoro Foundation, IRCCS, Medical Center of Rehabilitation, Cassano M., Bari, Italy.
Int J Cardiol. 1995 May;49(3):215-23. doi: 10.1016/0167-5273(95)02307-i.
This study was undertaken to assess the relation of ambulatory myocardial ischemia to heart rate changes and variability in exercise threshold in patients with chronic angina. The study involved 118 patients with chronic angina and proven coronary artery disease who had a 'positive' exercise test result. All patients underwent a first exercise test followed by a 48-h period of ambulatory electrocardiographic monitoring. A second exercise test was performed 4 days later. A total of 101 ischemic episodes were recorded in 35 patients. The heart rate at the appearance of 1-mm ST segment depression during ambulatory electrocardiographic monitoring was > or = 20 beats/min lower than that during exercise testing in 58 ischemic episodes (57%, Group A), 10-19 beats/min lower in 26 (26%, Group B), and < or = 9 beats/min lower or higher in 17 (17%, Group C). Thirty-five percent of the Group A ischemic episodes, 69% of Group B, and 71% of Group C were preceded by an increase in heart rate of > or = 10 beats/min. Thirty patients showed a variable exercise threshold. The prevalence of Group A and B ischemic episodes was not significantly different in patients with fixed or variable exercise threshold, whereas that of Group C episodes was 22% in the former and 0% in the latter (P = 0.036). These results suggest that increased coronary tone may be one of the mechanisms contributing to modulate the occurrence of transient myocardial ischemia in most patients with chronic angina and transient myocardial ischemia at ambulatory electrocardiographic monitoring. This occurs regardless of whether the patients have a variable or fixed exercise threshold.
本研究旨在评估慢性心绞痛患者动态心肌缺血与心率变化及运动阈值变异性之间的关系。该研究纳入了118例慢性心绞痛且经证实患有冠状动脉疾病且运动试验结果为“阳性”的患者。所有患者均先进行一次运动试验，随后进行48小时的动态心电图监测。4天后进行第二次运动试验。35例患者共记录到101次缺血发作。在58次缺血发作（57%，A组）中，动态心电图监测出现1毫米ST段压低时的心率比运动试验时低≥20次/分钟；在26次（26%，B组）中低10 - 19次/分钟；在17次（17%，C组）中低≤9次/分钟或更高。A组缺血发作的35%、B组的69%和C组的71%在发作前心率增加≥10次/分钟。30例患者表现出运动阈值可变。运动阈值固定或可变的患者中，A组和B组缺血发作的患病率无显著差异，而C组发作在前者中的患病率为22%，在后者中为0%（P = 0.036）。这些结果表明，冠状动脉张力增加可能是大多数慢性心绞痛患者动态心电图监测时短暂性心肌缺血发生机制之一，无论患者运动阈值可变或固定。
