Grubb N R, Fox K A, Cawood P
Cardiovascular Research Unit, University of Edinburgh, UK.
Resuscitation. 1996 Nov;33(1):35-41. doi: 10.1016/s0300-9572(96)00971-9.
diagnosis of precipitating myocardial infarction is essential for management of victims of out-of-hospital cardiac arrest, since investigations and treatment are determined by the underlying cause. Skeletal muscle and myocardial damage from external cardiac massage and defibrillation may complicate biochemical diagnosis of myocardial infarction.
(a) to examine the relationship between cumulative defibrillation energy and serum levels of cardiac troponin T and MB creatine kinase (MB-CK) mass in out-of-hospital cardiac arrest survivors without electrocardiographic evidence of myocardial infarction; (b) to reassess diagnostic thresholds for myocardial infarction using MB-CK mass and troponin T in this setting.
77 victims of out-of-hospital cardiac arrest were studied. Serum was obtained for MB-CK mass, CK and troponin T estimation on the first 4 days of admission. Patients were divided into three groups using electrocardiographic criteria: group 1, myocardial infarction; group 2, no evidence of infarction; and group 3, equivocal electrocardiograms. Correlation coefficients were calculated for highest recorded levels of the biochemical markers versus defibrillation energy. Receiver-operating characteristic plots were used to determine optimum biochemical diagnostic thresholds for subjects in groups 1 and 2.
using predefined criteria, 27 patients had myocardial infarction, 34 did not have myocardial infarction and 16 had equivocal electrocardiograms. Significant correlations were found for defibrillation energy versus log troponin T (r = 0.42, P < 0.05), log MB-CK mass (r = 0.51, P < 0.01) and total CK (r = 0.68, P < 0.001) in group 2. Within groups 1 and 2, MB-CK mass and troponin T provided additional diagnostic value over MB-CK fraction (P < 0.001). Diagnostic accuracy was not improved by adjusting for shock energy. The optimum threshold value was 4 ng/ml for troponin T (sensitivity 88%, specificity 95%), 60 ng/ml for MB-CK mass (sensitivity 88%, specificity 88%) and 8% of total CK for MB-CK fraction (sensitivity 74%, specificity 82%). These values should be interpreted with caution, since this study is limited by the exclusion of patients with uncertain electrocardiographic diagnoses into group 3.
skeletal muscle and myocardial damage occurs in survivors of out-of-hospital cardiac arrest and is related to the duration of resuscitation. This complicates biochemical diagnosis of underlying myocardial infarction. Specific high diagnostic threshold values for MB-CK and troponin T are needed to optimise diagnostic accuracy. The use of MB-CK fraction leads to greater diagnostic error because of the variability of muscle CK release after resuscitation.
对于院外心脏骤停患者的管理而言，明确引发心肌梗死的诊断至关重要，因为检查和治疗取决于潜在病因。体外心脏按压和除颤导致的骨骼肌及心肌损伤可能会使心肌梗死的生化诊断变得复杂。
（a）在无心肌梗死心电图证据的院外心脏骤停幸存者中，研究累积除颤能量与心肌肌钙蛋白T及肌酸激酶同工酶MB（MB-CK）质量的血清水平之间的关系；（b）在此情况下，重新评估使用MB-CK质量和肌钙蛋白T诊断心肌梗死的阈值。
对77例院外心脏骤停患者进行研究。在入院的前4天采集血清，用于测定MB-CK质量、肌酸激酶（CK）和肌钙蛋白T。根据心电图标准将患者分为三组：第1组，心肌梗死；第2组，无梗死证据；第3组，心电图不明确。计算生化标志物的最高记录水平与除颤能量的相关系数。采用受试者操作特征曲线来确定第1组和第2组受试者的最佳生化诊断阈值。
根据预定义标准，27例患者发生心肌梗死，34例未发生心肌梗死，16例心电图不明确。在第2组中，除颤能量与肌钙蛋白T的对数（r = 0.42，P < 0.05）、MB-CK质量的对数（r = 0.51，P < 0.01）和总CK（r = 0.68，P < 0.001）之间存在显著相关性。在第1组和第2组中，MB-CK质量和肌钙蛋白T比CK同工酶（MB-CK）提供了更多的诊断价值（P < 0.001）。调整休克能量后，诊断准确性并未提高。肌钙蛋白T的最佳阈值为4 ng/ml（敏感性88%，特异性95%），MB-CK质量为60 ng/ml（敏感性88%，特异性88%），MB-CK同工酶占总CK的8%（敏感性74%，特异性82%）。这些值应谨慎解读，因为本研究因将心电图诊断不确定的患者排除在第3组而受到限制。
院外心脏骤停幸存者会发生骨骼肌和心肌损伤，且与复苏持续时间有关。这使潜在心肌梗死的生化诊断变得复杂。需要特定的高诊断阈值来优化MB-CK和肌钙蛋白T的诊断准确性。由于复苏后肌肉CK释放存在变异性，使用CK同工酶会导致更大的诊断误差。
