Heart with ECG waveforms illustrating normal and NASTEP patterns.

Decoding Heart Attack Signals: Beyond the Standard ST-Elevation

Jordan Keane in Health & Wellness December 2025 • 4 min read.

"What are NASTEP patterns, and how do they challenge our understanding of acute coronary syndromes?"

When someone experiences symptoms suggestive of a heart attack, emergency medical teams and doctors in the emergency room often rely on an electrocardiogram (ECG) to quickly assess the situation. One of the key indicators they look for is ST-segment elevation, a specific pattern on the ECG that typically signals a severe blockage in a coronary artery, necessitating immediate intervention to restore blood flow to the heart.

However, not all ST-segment elevations are created equal. Sometimes, these patterns appear in the absence of an acute coronary blockage, leading to a diagnostic conundrum. These non-acute ST-elevation patterns, or NASTEP, can be caused by a variety of conditions, some benign and others potentially life-threatening. Recognizing and understanding NASTEP is crucial to avoid unnecessary interventions and ensure appropriate management.

This article delves into the world of NASTEP, exploring its various forms, underlying causes, and the challenges it presents in clinical practice. By shedding light on this complex topic, we aim to empower individuals and healthcare professionals alike to better navigate the intricacies of heart attack diagnosis and treatment.

Unmasking NASTEP: Beyond the Typical Heart Attack

Heart with ECG waveforms illustrating normal and NASTEP patterns.

NASTEP, or Non-Acute ST-Elevation Patterns, refers to ST-segment elevations observed on an ECG that are not directly caused by a sudden, complete blockage of a coronary artery. Unlike the ST-elevation seen in a classic heart attack (STEMI), NASTEP can arise from a variety of cardiac and non-cardiac conditions. Recognizing NASTEP is essential to prevent misdiagnosis and ensure that patients receive the correct treatment.

Several conditions can mimic the ST-elevation seen in acute myocardial infarction. Some of the notable causes include:

Takotsubo Syndrome: Often triggered by emotional or physical stress, this condition, also known as broken heart syndrome, can cause ST-elevation and heart muscle dysfunction.
Pericarditis: Inflammation of the sac surrounding the heart can lead to widespread ST-elevation on the ECG.
Early Repolarization: A normal variant, particularly common in young, healthy individuals, that can cause subtle ST-elevation, often mistaken for acute ischemia.
Left Ventricular Hypertrophy: Enlargement of the heart's main pumping chamber can alter the ECG, sometimes producing ST-elevation.
Brugada Syndrome: A genetic condition that affects the heart's electrical system, predisposing individuals to arrhythmias and sudden cardiac death; it often presents with ST-elevation in the right precordial leads.

Differentiating NASTEP from acute STEMI requires a careful evaluation of the patient's clinical presentation, medical history, and additional diagnostic tests. Doctors often consider factors such as the patient's symptoms, risk factors for heart disease, and the specific characteristics of the ST-elevation on the ECG. Blood tests to measure cardiac enzymes, such as troponin, can also help distinguish between acute myocardial damage and other causes of ST-elevation.

Moving Forward: Improving NASTEP Recognition and Management

As research continues to unravel the complexities of NASTEP, healthcare professionals are gaining a better understanding of how to differentiate these patterns from acute STEMI. This improved recognition, combined with appropriate diagnostic testing and tailored treatment strategies, ultimately leads to better outcomes for patients presenting with ST-elevation on their ECGs. By staying informed and vigilant, we can ensure that individuals receive the right care at the right time, preserving heart health and improving overall well-being.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1111/anec.12605, Alternate LINK

Title: The Non-Acute Coronary Syndrome Related St-Elevation Patterns (Nastep) Conundrum: War Helmets, Greek Letters, And… “Shark Fins”

Subject: Physiology (medical)

Journal: Annals of Noninvasive Electrocardiology

Publisher: Wiley

Authors: Nicola Tarantino, Francesco Santoro, Matteo Di Biase, Natale Daniele Brunetti

Published: 2018-10-11

Everything You Need To Know

What are NASTEP patterns and how do they differ from a typical heart attack, like STEMI?

NASTEP, or Non-Acute ST-Elevation Patterns, describes ST-segment elevations on an ECG that aren't caused by a sudden, complete blockage of a coronary artery. Unlike STEMI (ST-Elevation Myocardial Infarction), the classic type of heart attack, NASTEP arises from various cardiac and non-cardiac conditions. Recognizing this difference is crucial to avoid misdiagnosis and ensure the appropriate treatment is given. The main difference lies in the cause of the ST-segment elevation. STEMI is due to an acute blockage, while NASTEP arises from other conditions such as Takotsubo Syndrome, Pericarditis, Early Repolarization, Left Ventricular Hypertrophy, or Brugada Syndrome.

What conditions can cause NASTEP, and why is it important to identify them correctly?

Several conditions can mimic the ST-elevation seen in acute myocardial infarction, leading to NASTEP. These include Takotsubo Syndrome (broken heart syndrome), Pericarditis (inflammation of the sac surrounding the heart), Early Repolarization (a normal variant), Left Ventricular Hypertrophy (enlargement of the heart's main pumping chamber), and Brugada Syndrome (a genetic condition). Identifying the correct cause of ST-elevation is crucial to avoid unnecessary interventions (like procedures for a blocked artery when one doesn't exist) and to ensure patients receive the specific treatment they need for their actual condition. For example, treating Pericarditis would be vastly different than treating a STEMI.

How is NASTEP diagnosed, and what diagnostic tests are used?

Diagnosing NASTEP involves a comprehensive evaluation. Doctors consider the patient's symptoms, medical history, and risk factors for heart disease. Crucially, they analyze the ECG characteristics. Additional diagnostic tests play a key role. Blood tests to measure cardiac enzymes, like troponin, are used to differentiate between acute myocardial damage and other causes of ST-elevation. These tests help determine if the heart muscle has been damaged, which helps in differentiating between conditions like STEMI and NASTEP. Moreover, differentiating NASTEP from acute STEMI may need additional tests and a careful patient assessment.

What is Takotsubo Syndrome, and how does it relate to NASTEP?

Takotsubo Syndrome, often triggered by emotional or physical stress, is a condition that can cause ST-elevation on an ECG, leading to its classification as a form of NASTEP. It is also known as broken heart syndrome, and it can cause heart muscle dysfunction. Because it presents with ST-segment elevation, it can be mistaken for a heart attack (STEMI). However, the underlying cause and treatment are different, making accurate diagnosis essential.

Why is understanding and recognizing NASTEP important for patient outcomes?

Understanding and recognizing NASTEP is vital for improving patient outcomes by ensuring that individuals receive the correct care at the right time. Accurate diagnosis prevents unnecessary treatments, such as invasive procedures for a heart attack when the patient doesn't have one, and directs patients to the specific treatments they need. This approach preserves heart health and enhances overall well-being by ensuring that patients receive the most effective and appropriate interventions based on their actual condition. Improved recognition, combined with appropriate diagnostic testing and tailored treatment strategies, ultimately leads to better outcomes for patients presenting with ST-elevation on their ECGs.