Hackshaw B T
Eisenhower Medical Center, Rancho Mirage, California.
Am J Med. 1992 May 27;92(5A):46S-51S. doi: 10.1016/0002-9343(92)80056-6.
Angina pectoris is chest discomfort associated with myocardial ischemia. When coronary blood flow is inadequate to meet myocardial tissue demand, lactate accumulates, resulting in diastolic and systolic left ventricular dysfunction. This leads to ST-segment abnormalities and eventually to angina pectoris. Angina, most commonly a pressure-type sensation in the midanterior chest precipitated by exercise, stress, or cold, typically lasts 1-5 minutes and is alleviated by rest or nitroglycerin. Diagnostic studies to assess myocardial ischemia include treadmill exercise testing, Holter monitoring, and coronary angiography. Treadmill exercise testing has a relatively low accuracy for diagnosing coronary artery disease. This can be improved by combining exercise with thallium-201 imaging, two-dimensional echocardiography, or positron emission tomography (PET). Thallium-201 scintigraphy and exercise echocardiography have reported sensitivities of 70-85% and specificities of 50-60% when applied to low-risk, asymptomatic populations. PET scanning has a high predictive accuracy (sensitivity 90%, specificity 90-95%) and is more useful as a screening test; it can also assess the functional significance of coronary artery stenoses and differentiate viable myocardium from infarcted tissue. Holter monitoring is too insensitive and nonspecific to be used as a screening test for coronary artery disease; it can, however, assess the total ischemic burden in patients with known coronary artery disease and correlate symptoms and ST-segment abnormalities during episodes of pain at rest. Coronary angiography has been the gold standard for diagnosing coronary artery stenoses. Quantitative angiography has improved the assessment of coronary artery narrowing but is still limited in evaluating coronary blood flow. Doppler flow studies provide useful information regarding coronary flow reserve. Myocardial ischemia as a cause of chest pain is determined by evaluating the clinical characteristics consistent with angina, correlating electrocardiographic abnormalities with perfusion defects or wall motion abnormalities, and determining the extent and functional significance of coronary artery stenoses by coronary angiography.
心绞痛是与心肌缺血相关的胸部不适。当冠状动脉血流不足以满足心肌组织需求时，乳酸会积聚，导致左心室舒张和收缩功能障碍。这会导致ST段异常，最终引发心绞痛。心绞痛最常见的表现是运动、压力或寒冷诱发的胸前中部压榨样感觉，通常持续1 - 5分钟，休息或使用硝酸甘油可缓解。评估心肌缺血的诊断性检查包括跑步机运动试验、动态心电图监测和冠状动脉造影。跑步机运动试验诊断冠状动脉疾病的准确性相对较低。通过将运动与铊-201显像、二维超声心动图或正电子发射断层扫描（PET）相结合可提高其准确性。铊-201闪烁扫描和运动超声心动图应用于低风险无症状人群时，报告的敏感性为70 - 85%，特异性为50 - 60%。PET扫描具有较高的预测准确性（敏感性90%，特异性90 - 95%），作为筛查试验更有用；它还可以评估冠状动脉狭窄的功能意义，并区分存活心肌和梗死组织。动态心电图监测对冠状动脉疾病的敏感性和特异性太低，不能用作筛查试验；然而，它可以评估已知冠状动脉疾病患者的总缺血负荷，并将休息时疼痛发作期间的症状与ST段异常相关联。冠状动脉造影一直是诊断冠状动脉狭窄狭窄的金标准。定量血管造影改善了对冠状动脉狭窄的评估，但在评估冠状动脉血流方面仍有局限性。多普勒血流研究提供了有关冠状动脉血流储备的有用信息。作为胸痛原因的心肌缺血通过评估与心绞痛一致的临床特征、将心电图异常与灌注缺损或室壁运动异常相关联以及通过冠状动脉造影确定冠状动脉狭窄的程度和功能意义来确定。
