Top Updates in 2025 ACS Management Guidelines

Medscape

14 hours ago

The 2025 American Heart Association/American College of Cardiology Guidelines on the management of acute coronary syndromes (ACS) were finally published recently, marking the first update after an 11-year hiatus.
Despite this long gap, most acute care clinicians have remained current on ACS management through the European guidelines and other continuing medical education sources. Still, many of us have been eager to see whether the new US guidelines would contain any surprises or major breakthroughs.
For those that have kept up with the literature on accelerated diagnostic protocols, troponins, anticoagulants, and related topics, the new guidelines may not feel groundbreaking. Nonetheless, the publication provided some critical reminders and a few key updates that all acute care providers should know.
What follows is a selection of the most important takeaways, in my opinion, for providing acute care to patients presenting with ACS. This is not intended to be a comprehensive review of ACS management or of concepts that are already well-established in current practice.
Key Points and Updated Information
Posterior MI remains underdiagnosed. Missed or delayed diagnosis of acute posterior myocardial infarction (MI) remains common in acute care, largely because ST-segment elevation (STE) is lacking on the standard 12-lead ECG. Instead, these patients tend to present with ST-segment depression in the right precordial leads V1-V3. The authors remind us that the recommended method of detecting posterior MI is through the use of posterior leads in any patients with concerning symptoms and ST-depression in the right precordial leads. If ≥ 0.5 mm of STE is present in any one of the posterior leads, the diagnosis of acute posterior MI is made and justifies acute reperfusion therapy (ie, thrombolytics or immediate cardiac catheterization/percutaneous coronary intervention).
Missed or delayed diagnosis of acute posterior myocardial infarction (MI) remains common in acute care, largely because ST-segment elevation (STE) is lacking on the standard 12-lead ECG. Instead, these patients tend to present with ST-segment depression in the right precordial leads V1-V3. The authors remind us that the recommended method of detecting posterior MI is through the use of posterior leads in any patients with concerning symptoms and ST-depression in the right precordial leads. If ≥ 0.5 mm of STE is present in any one of the posterior leads, the diagnosis of acute posterior MI is made and justifies acute reperfusion therapy (ie, thrombolytics or immediate cardiac catheterization/percutaneous coronary intervention). A normal ECG does not rule out ACS. The authors also remind us that the absence of electrocardiographic findings of ischemia does not rule out ACS.
The authors also remind us that the absence of electrocardiographic findings of ischemia does not rule out ACS. Troponin-negative ACS ('unstable angina') still exists. The authors spend some time reviewing the pathophysiology of ACS and its correlation with troponin elevation. In this section, they remind us of a critical point: 'Unstable angina' (ie, troponin-negative ACS) still exists, even in this day of highly sensitive troponins. Just as they have reminded us that a nonischemic ECG does not rule out ACS, a negative troponin does not rule out ACS.
They also remind us that even in the setting of a STEMI, a troponin test may be negative if measured within a short time from the onset of symptoms.
The authors spend some time reviewing the pathophysiology of ACS and its correlation with troponin elevation. In this section, they remind us of a critical point: 'Unstable angina' (ie, troponin-negative ACS) still exists, even in this day of highly sensitive troponins. Just as they have reminded us that a nonischemic ECG does not rule out ACS, a negative troponin does not rule out ACS. They also remind us that even in the setting of a STEMI, a troponin test may be negative if measured within a short time from the onset of symptoms. Repeat ECGs are essential. The importance of serial ECG testing in patients with concerning symptoms and initially negative ECGs is emphasized. The authors state that 11% of patients ultimately diagnosed with STEMI had an initial ECG that was negative. Therefore, failure to repeat ECGs in this group of patients can result in a significant number of missed STEMIs and, in my experience, has been a common complaint in litigated cases.
The importance of serial ECG testing in patients with concerning symptoms and initially negative ECGs is emphasized. The authors state that 11% of patients ultimately diagnosed with STEMI had an initial ECG that was negative. Therefore, failure to repeat ECGs in this group of patients can result in a significant number of missed STEMIs and, in my experience, has been a common complaint in litigated cases. Some patients require urgent catheterization despite the absence of STE. Another common cause of litigation is failure of healthcare providers to remember that there are groups of patients that need immediate cardiac catheterization despite the absence of STE on the ECG. In fact, the guideline indicates that catheterization should be undergone within 2 hours (Class I recommendation). These patients with ACS are categorized as unstable or very high-risk, and they include: Patients in cardiogenic shock. Patients with signs or symptoms of acute heart failure, including new or worsening mitral regurgitation or acute pulmonary edema. Patients with refractory angina. Patients with hemodynamic or electrical instability (eg, sustained ventricular tachycardia or ventricular fibrillation).
Another common cause of litigation is failure of healthcare providers to remember that there are groups of patients that need immediate cardiac catheterization despite the absence of STE on the ECG. In fact, the guideline indicates that catheterization should be undergone within 2 hours (Class I recommendation). These patients with ACS are categorized as unstable or very high-risk, and they include: Blood transfusion thresholds remain uncertain. The indication for blood transfusion in patients with ACS has been a source of uncertainty for decades. Although large randomized studies to provide a clear answer are still lacking, the authors suggest (Class IIb) that in patients with ACS and acute or chronic anemia, packed cell transfusions should be provided to achieve a hemoglobin level ≥ 10 g/dL in order to reduce cardiovascular events.
Viewpoint
The ability to manage ACS in an evidence-based manner is critical to anyone who practices acute care medicine. These most recent US guidelines provide a fairly comprehensive review of the management of ACS, and I recommend a thorough read of the entire publication. However, I would most strongly emphasize knowledge of the points noted above because, in my experience, these have continued to be a source of confusion or missed opportunities to diagnose and properly manage this high-risk group of patients.
Amal Mattu, MD, is a professor, vice chair of education, and co-director of the emergency cardiology fellowship in the Department of Emergency Medicine at the University of Maryland School of Medicine in Baltimore. Follow Dr Mattu on X.