Tofler G H, Muller J E, Stone P H, Forman S, Solomon R E, Knatterud G L, Braunwald E
Division of Cardiology, New England Deaconess Hospital, Boston, Massachusetts.
J Am Coll Cardiol. 1992 Nov 1;20(5):1049-55. doi: 10.1016/0735-1097(92)90356-r.
The aim of this study was to provide insight into the mechanism of acute myocardial infarction by determining the modifiers of timing and possible triggers of onset of infarction.
A higher frequency of onset of acute myocardial infarction has been reported in the morning with a peak in the 1st 3 h after awakening. This observation suggests that the onset of infarction may be triggered by activity in the morning and at other times of the day.
The clinical history of the 3,339 patients entered into the Thrombolysis in Myocardial Infarction phase II study was analyzed to determine characteristics predicting a higher frequency of infarction between 6 AM and noon, and onset of infarction during exertion.
A higher proportion (34.4%) of infarctions began in the morning (6 AM to noon) compared with other times of the day. Characteristics independently predicting a higher frequency between 6 AM to noon were no beta-adrenergic blocking agent use in the 24 h before infarction, no discomfort other than the index pain in the preceding 48 h, occurrence of the infarction on a weekday and no history of current smoking. In 18.7% of patients, infarction occurred during moderate or marked physical activity. Independent predictors of exertion-related infarction included male gender, no history of current smoking, white race, no use of calcium channel blocking agents or nitrates in the preceding 24 h, the absence of either chest pain at rest in the 3 weeks before infarction or any pain in the preceding 48 h, the absence of new onset angina and the presence of exertional pain in the preceding 3 weeks. Compared with patients whose infarction occurred at rest or during mild activity, those with exertion-related infarction had fewer coronary vessels with > or = 60% stenosis (p = 0.002) and were more likely to have an occluded infarct-related vessel after thrombolytic therapy (p = 0.01).
Further study of the timing and activity at onset of infarction may provide insight into the pathophysiologic mechanisms causing acute myocardial infarction and provide clues to preventive measures.
本研究旨在通过确定梗死发生时间的调节因素和可能的触发因素，深入了解急性心肌梗死的机制。
据报道，急性心肌梗死在早晨发作的频率较高，在醒来后的前3小时达到峰值。这一观察结果表明，梗死的发作可能由早晨及一天中其他时间的活动触发。
分析了纳入心肌梗死溶栓治疗二期研究的3339例患者的临床病史，以确定预测上午6点至中午梗死频率较高以及运动时梗死发作的特征。
与一天中的其他时间相比，更高比例（34.4%）的梗死发生在早晨（上午6点至中午）。独立预测上午6点至中午梗死频率较高的特征包括梗死前24小时未使用β-肾上腺素能阻滞剂、前48小时除指数疼痛外无其他不适、梗死发生在工作日且无当前吸烟史。在18.7%的患者中，梗死发生在中度或剧烈体力活动期间。与运动相关梗死的独立预测因素包括男性、无当前吸烟史、白种人、梗死前24小时未使用钙通道阻滞剂或硝酸盐、梗死前3周无静息胸痛或前48小时无任何疼痛、无新发心绞痛以及前3周存在运动性疼痛。与梗死发生在休息时或轻度活动期间的患者相比，与运动相关梗死的患者冠状动脉狭窄≥60%的血管较少（p = 0.002），且溶栓治疗后梗死相关血管闭塞的可能性更大（p = 0.01）。
对梗死发作时间和活动的进一步研究可能有助于深入了解导致急性心肌梗死的病理生理机制，并为预防措施提供线索。
