Cardiology Department, Amsterdam University Medical Center, Amsterdam, The Netherlands; Cardiology Department, Leiden University Medical Center, Leiden, The Netherlands.
Cardiology Department, Leiden University Medical Center, Leiden, The Netherlands.
J Electrocardiol. 2023 Nov-Dec;81:75-79. doi: 10.1016/j.jelectrocard.2023.08.007. Epub 2023 Aug 19.
The ECG is crucial in the prehospital (and early inhospital) phase of patients with symptoms suggestive of myocardial ischemia. Therefore, new algorithms for ECG-based myocardial ischemia detection are continuously being researched. Development and validation of these algorithms require a database of acute ECGs (from the prehospital or emergency department setting) including a representative mix of cases (ischemia present) and controls (no ischemia present). Therefore, for every patient in this mix, the "truth" regarding the actual presence or absence of myocardial ischemia during the recording of the acute ECG has to be determined to compare the newly developed algorithm against. This post hoc adjudication process of determining whether an acute (either prehospitally acquired or acquired in the emergency department) ECG was made under ischemic conditions should use all available clinical data (the clinical diagnosis, cardiac imaging data, and laboratory values) of the subsequent patient's admission. Even with all data at hand, post hoc labeling a patient and their acute ECG as a myocardial ischemia case or control cannot be forced into a binary division between definite cases and definite controls. More specifically, to be used for the development of a new algorithm, the patients' ECG has to be scored for the presence or absence of myocardial ischemia at the exact moment of its recording, which renders the classification even more difficult. For instance, even though it may be plausible that myocardial ischemia was present at a given moment during the patient's admission, this is not necessarily proof that the prehospital (or early inhospital) ECG was also made in ischemic conditions: ischemia can be a fluctuating process (as is, e.g., the case in unstable angina pectoris). Therefore, post hoc classification of an acute ECG in terms of the absence or presence of ischemia requires a multipoint scale ranging between definite ischemic to definite non-ischemic, for instance using a 5-point scale (presumed non-ischemic, probably non-ischemic, uncertain, probably ischemic, presumed ischemic). To summarize, the post hoc adjudication process of ECGs of ambulance (and emergency department) patients cannot result in a binary division into definite cases and controls (i.e., patients with or without myocardial ischemia during the recording of the acute ECG), as myocardial ischemia is often dynamic rather than constant. ECGs could be labeled on a multi-point scale, in which the label represents the probability of the actual presence (or absence) of myocardial ischemia at the exact moment of the recording of that ECG. Further development of algorithms for myocardial ischemia detection should consider this concept.
心电图在有心肌缺血症状的患者的院前（和早期院内）阶段至关重要。因此，不断研究基于心电图的心肌缺血检测新算法。这些算法的开发和验证需要一个急性心电图数据库（来自院前或急诊科环境），其中包括具有代表性的病例组合（存在缺血）和对照（不存在缺血）。因此，对于该组合中的每个患者，都必须确定记录急性心电图期间实际存在或不存在心肌缺血的“真相”，以便将新开发的算法与之进行比较。这种事后确定急性（无论是院前获得还是在急诊科获得）心电图是否在缺血条件下进行的裁决过程应该使用随后患者入院的所有可用临床数据（临床诊断、心脏成像数据和实验室值）。即使手头有所有数据，事后将患者及其急性心电图标记为心肌缺血病例或对照也不能强行分为明确病例和明确对照。更具体地说，为了开发新算法，必须在记录心电图的那一刻对患者心电图是否存在心肌缺血进行评分，这使得分类更加困难。例如，即使在患者入院期间的某个特定时刻存在心肌缺血是合理的，但这并不一定证明院前（或早期院内）心电图也是在缺血条件下进行的：缺血可能是一个波动的过程（例如不稳定型心绞痛就是这种情况）。因此，事后根据缺血的有无对急性心电图进行分类需要使用介于明确缺血和明确非缺血之间的多点量表，例如使用 5 点量表（假定非缺血、可能非缺血、不确定、可能缺血、假定缺血）。总之，救护车（和急诊科）患者心电图的事后裁决过程不能导致明确病例和对照的二分法（即在记录急性心电图期间存在或不存在心肌缺血的患者），因为心肌缺血通常是动态的而不是恒定的。心电图可以标记为多点量表，其中标签代表在记录该心电图的确切时刻实际存在（或不存在）心肌缺血的概率。用于心肌缺血检测的算法的进一步开发应该考虑到这一概念。
