Acute Coronary Syndromes

Diagnosis and treatment
Introduction
Acute coronary syndromes (ACS) include “a broad spectrum of clinical presentations, spanning ST-segment-elevation myocardial infarction, through to an accelerated pattern of angina without evidence of myonecrosis”.1

Please see Guidelines for the management patients with ST-elevation myocardial infarction
                Guidelines for the management of patients with unstable angina and non-ST-elevation myocardial infarction
New acute coronary syndromes terminology and implications for diagnosis
The terminology used to describe ACS continues to evolve, with the emergence of the term “non-ST-segment-elevation acute coronary syndrome” (NSTEACS). This reflects a shift away from establishing a definitive diagnosis at presentation, and towards a more clinically appropriate strategy of forming a rapid working diagnosis with its implications for initial clinical decision making.
At presentation, the initial diagnostic nomenclature focuses on risk stratification to direct treatment strategies. Establishing a definitive diagnosis often requires time, particularly for evidence of myocardial necrosis to emerge, and has important implications pertaining to prognosis, diagnostic coding, and social issues such as insurance and licensure. See Box 1for a representation of diagnosis over time, from presentation to final diagnosis.


1 Defining acute coronary syndromes over time: presentation to final diagnosis


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ECG = electrocardiogram.

Initial working diagnosis

The initial working diagnosis is based on the clinical presentation and the initial electrocardiogram (ECG) findings and, in particular, the presence or absence of ST-segment elevation. As the vast majority of patients who present with initial ST-segment elevation develop biochemical evidence of myonecrosis, the term “ST-segment-elevation myocardial infarction” (STEMI) is often used from the outset in these patients....