Svedjeholm R, Dahlin L G, Lundberg C, Szabo Z, Kågedal B, Nylander E, Olin C, Rutberg H
Department of Cardiothoracic Surgery, Linköping Heart Center, University Hospital, Sweden.
Eur J Cardiothorac Surg. 1998 Jun;13(6):655-61. doi: 10.1016/s1010-7940(98)00091-8.
A major assumption in cardiovascular medicine is that Q-waves on the electrocardiogram indicate major myocardial tissue damage. The appearance of a new Q-wave has therefore been considered the most reliable criterion for diagnosis of perioperative myocardial infarction (PMI) in cardiac surgery. In a study, originally intended to evaluate troponin-T as a marker of PMI, analysis of our data aroused the need to address the reliability of Q-wave criteria for diagnosis of PMI.
In 302 consecutive patients undergoing coronary surgery, Q-wave and other electrocardiogram (ECG) criteria were compared with biochemical markers of myocardial injury and the postoperative course. All ECGs were analysed by a cardiologist blinded to the biochemical analyses and the clinical course.
The incidence of positive Q-wave criteria was 8.1%. Combined biochemical (CK-MB > or = 70 microg/l) and Q-wave criteria were found in 1.0%. Patients with new Q-waves did not have CK-MB or troponin-T levels significantly different from those without Q-waves. More than 25% of the Q-waves were associated with plasma troponin-T below the reference level (< 0.2 microg/l) on the fourth postoperative day. Q-wave criteria alone did not influence the postoperative course. In contrast, biochemical markers correlated with clinical outcome.
The majority of Q-waves appearing after coronary surgery were not associated with major myocardial tissue damage, and according to troponin-T one-fourth of the Q-waves were not associated with myocardial necrosis. Furthermore, the appearance of Q-waves had little influence on short term clinical outcome. Therefore, the use of Q-wave criteria as the gold standard for diagnosis of PMI may have to be questioned.
心血管医学中的一个主要假设是，心电图上的Q波表明心肌组织受到严重损伤。因此，新Q波的出现一直被认为是心脏手术中围手术期心肌梗死（PMI）诊断的最可靠标准。在一项原本旨在评估肌钙蛋白-T作为PMI标志物的研究中，对我们数据的分析引发了对Q波标准用于PMI诊断可靠性的探讨。
在302例连续接受冠状动脉手术的患者中，将Q波和其他心电图（ECG）标准与心肌损伤的生化标志物及术后病程进行比较。所有心电图均由一位对生化分析和临床病程不知情的心脏病专家进行分析。
Q波标准阳性的发生率为8.1%。生化指标（CK-MB≥70微克/升）和Q波标准同时阳性的发生率为1.0%。出现新Q波的患者其CK-MB或肌钙蛋白-T水平与未出现Q波的患者相比无显著差异。超过25%的Q波与术后第四天血浆肌钙蛋白-T低于参考水平（<0.2微克/升）相关。仅Q波标准对术后病程无影响。相比之下，生化标志物与临床结局相关。
冠状动脉手术后出现的大多数Q波与心肌组织严重损伤无关，根据肌钙蛋白-T，四分之一的Q波与心肌坏死无关。此外，Q波的出现对短期临床结局影响很小。因此，将Q波标准用作PMI诊断的金标准可能需要受到质疑。
