Purpose: The Fourth Universal Definition of Myocardial Infarction (MI) has highlighted the different pathophysiological mechanisms that may lead to ischaemic and non-ischaemic myocardial injury and has emphasised that the diagnosis of myocardial infarction requires the presence of acute myocardial ischaemia in the setting of acute myocardial injury. This case based review intends to illustrate basic principles on how to apply this new, revised definition in clinical practice.Methods and Results: The distinction between different types of MIs (type 1 or type 2) and the delineation of MI from acute non-ischaemic myocardial injury may be challenging in individual patients, which is illustrated by presenting and discussing real-life routine cases.Conclusions: Type 1 MI is a consequence of coronary plaque rupture or erosion with intracoronary thrombus formation that is usually apparent on coronary angiography. Plausible triggering mechanisms causing myocardial oxygen supply/demand mismatch must be identified for the diagnosis of type 2 MI and its treatment should focus initially on management of the underlying disease attributable to acute myocardial ischaemia.

中文翻译：

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心肌梗死的第四个普遍定义在临床实践中的应用。

目的：《心肌梗死的第四个普遍定义》强调了可能导致缺血性和非缺血性心肌损伤的不同病理生理机制，并强调诊断心肌梗塞需要在急性环境中存在急性心肌缺血心肌损伤。这项基于病例的综述旨在说明如何在临床实践中应用这一新的，经过修订的定义的基本原则。方法和结果：不同类型的心梗（1型或2型）之间的区别以及对急性非缺血性心肌梗死的描述对个别患者而言，心肌损伤可能具有挑战性，这可以通过介绍和讨论现实生活中的常规病例来说明。1型MI是冠状动脉斑块破裂或冠状动脉内血栓形成的侵蚀的结果，通常在冠状动脉造影上很明显。对于2型MI的诊断，必须确定引起心肌供氧/需求失配的合理触发机制，其治疗应首先着重于管理由急性心肌缺血引起的潜在疾病。