Chest Pain And Heart Attack Risk: What Emergency Doctors Look For First

Risk Stratification Of ACS In The Emergency Department

History
Recent studies have shown that history taking and physical examination alone are insufficient when evaluating patients with acute chest pain. Some clinical signs are more specific for ACS or MI than others, but they are not accurate enough to reliably assign patients to specific risk groups.

Studies have demonstrated that the most specific indicators of ACS include pain radiating to the right arm or both arms, a history of angina or MI, and increased sweating associated with pain. Symptoms such as nausea, vomiting, symptom relief after nitroglycerin administration, or detailed pain description were found to be considerably less reliable and less clinically significant.

Pain scales have recently become more widely used in clinical practice. However, studies have shown that short-term outcomes within 30 days do not significantly differ regardless of whether chest pain is rated as very severe (9–10 points) or milder.

Cardiovascular Risk Factors
Traditional cardiovascular risk factors such as hypertension, diabetes mellitus, dyslipidemia, and smoking are widely used when assessing long-term cardiovascular risk. However, these risk factors are less useful in predicting ACS in symptomatic patients, as up to 12% of patients with acute MI have no typical cardiovascular risk factors.

Cardiological History
Patients with previously normal exercise stress test results have the same 30-day risk of adverse cardiovascular events as patients who have never undergone this test.

Exercise testing does not determine whether a non-obstructive atherosclerotic plaque may later rupture and cause ischemia; therefore, it is not particularly useful for assessing ACS risk. Coronary angiography is significantly more informative in this setting.

Patients with minimal coronary stenosis (up to 25%) or no stenosis had only a 10% risk of developing single-vessel coronary disease over a ten-year period and less than a 2% risk of acute MI. These findings suggest that ACS is unlikely in patients with previously normal coronary angiography results.

Physical Patient Examination
Clinical studies have shown that hypotension is one of the most important clinical signs indicating possible acute heart failure and the need for urgent treatment.

Chest pain that worsens with palpation reduces the likelihood of ACS, although such patients should still be monitored carefully.

Electrocardiogram
Current guidelines recommend recording and evaluating an electrocardiogram (ECG) within 10 minutes of a patient’s arrival at the emergency department. ECG remains the most important initial diagnostic test in suspected ACS.

In suspected ACS cases, ECG recordings should be repeated every 15–30 minutes during the first hour, as 1–6% of patients may still have ACS despite initially normal ECG findings.

An ECG without pathological changes is most commonly associated with occlusion of the left circumflex or right coronary artery. In these situations, additional V7–V9 leads may provide more diagnostic information. Additional right-sided leads (V3R–V4R) may also help detect right ventricular STEMI in cases of inferior wall myocardial infarction.

In STEMI cases, current guidelines recommend immediate percutaneous coronary intervention, except when only a left bundle branch block is present. The intervention should ideally be performed within 90–120 minutes from symptom onset. If this timeframe cannot be achieved, pharmacological thrombolysis is recommended.

False-positive ECG interpretations for STEMI occur in approximately 11–14% of cases, highlighting the importance of evaluating ECG findings alongside other clinical and laboratory data.

Imaging Methods
Chest X-ray is frequently performed in patients presenting to the emergency department with chest pain. It is useful for diagnosing conditions such as pneumonia or pneumothorax, although radiographic findings requiring interventional treatment are seen in only 6–12% of ACS cases.

Currently, there is insufficient evidence identifying which patient groups benefit most from routine chest X-ray evaluation.

Biochemical Markers
Since clinical examination alone is insufficient to confirm ACS, measurement of cardiac biomarkers such as troponin T or troponin I significantly improves early diagnosis.

According to the third universal definition of MI, cardiac troponins are essential biomarkers for detecting myocardial necrosis, and an increase or decrease in their blood concentration is necessary to confirm acute MI.

Troponin testing reflects the extent of cardiomyocyte death — the higher the troponin concentration, the larger the area of myocardial necrosis.

Experts emphasize that high-sensitivity troponin assays are important not only for early acute MI diagnosis but also for identifying smaller myocardial infarctions. However, elevated troponin concentrations may also occur in other cardiac conditions.

Any elevation in troponin concentration, regardless of its cause, is associated with increased morbidity and mortality risk. Emergency physicians should therefore pay close attention to such patients, as higher troponin concentrations are generally associated with worse prognosis.

When To Perform Troponin Blood Concentration Tests?
Current recommendations suggest measuring troponin concentration immediately upon patient arrival and again 3–6 hours after symptom onset. Additional testing beyond 6 hours may be performed if clinically indicated.

If the patient cannot accurately determine symptom onset, the time of arrival at the emergency department should be considered the starting point.

The introduction of high-sensitivity troponin assays, capable of detecting minimal myocardial injury shortly after symptom onset, has led to the development of rapid diagnostic algorithms for ruling out acute MI.

The 2015 European Society of Cardiology guidelines recommend troponin testing immediately and either after 3 hours or after 1 hour, depending on the specific clinical algorithm and patient group. These recommendations should always be interpreted in the context of all available clinical information.

If a patient presents very early after pain onset, troponin testing should be repeated after 3 hours because biomarker release depends on time. Delayed troponin elevation has also been described, therefore repeat testing is recommended if ACS suspicion persists or chest pain recurs.

Using the 3-hour algorithm, acute MI can be ruled out if high-sensitivity troponin levels remain within normal limits both at presentation and after 3 hours, the patient has no recurrent chest pain, and the in-hospital mortality risk assessed by the GRACE (Global Registry of Acute Coronary Events) score is below 140 points.

For patients presenting more than 6 hours after pain onset, a single blood test may be sufficient.

Application of this algorithm allows clinicians to reliably exclude MI in approximately 60% of patients with nonspecific ECG changes and accurately diagnose acute MI in approximately 70–80% of patients.

Even after acute MI has been ruled out, patients should undergo provocative stress testing either during hospitalization or on an outpatient basis.

It is important to note that although these algorithms confirm or exclude MI in most patients, some cases involve only minimal troponin elevation. In such situations, further diagnostic decisions should be based on the physician’s clinical judgment and experience.

Assessment Of Patient Risk Groups
Various scales and recommendations assist physicians in assigning patients to different ACS risk groups, predicting disease progression, and evaluating clinical symptoms alongside laboratory findings.

The most commonly used risk assessment tools in emergency departments are the TIMI (Thrombolysis in Myocardial Infarction) and HEART (History, ECG, Age, Risk Factors, Troponin) scores. Other available tools include PURSUIT, GRACE, Vancouver, and North American chest pain algorithms.

The modified TIMI score includes five criteria, each scored as 0 or 1 point. Evaluated factors include age, the presence of three or more cardiovascular risk factors, history of coronary heart disease (CHD), aspirin use during the previous 7 days, and anginal chest pain. The total score ranges from 0 to 5.

This scale helps differentiate ACS risk in the emergency department. Patients scoring 0 or 1 point are considered low risk. Due to its high negative predictive value (99.7%), TIMI is particularly effective at identifying patients unlikely to have ACS.

The HEART score evaluates five components, each scored from 0 to 2 points: patient history, ECG findings, age, CHD risk factors, and troponin levels. A total score of 3 or less classifies the patient as low risk.

Other ACS risk assessment methods are used less frequently but follow similar principles. For example, the North American Chest Pain Rule is highly effective in excluding patients without ACS symptoms, although its practical clinical utility has not yet been fully validated.

According to this rule, patients may be ruled out if the ECG shows no new ischemic changes, there is no history of CHD, the patient is younger than 40 years, chest pain is not typical of angina, and the initial troponin level is normal. In patients aged 41–50 years, repeat troponin testing after 6 hours is recommended.

The EDACS (Emergency Department Assessment of Chest Pain Score) is another method used to assess cardiac risk. This scale incorporates four categories: age group, gender, history of CHD or four cardiovascular risk factors, and four characteristics of chest pain.

A final EDACS score of ≤16, combined with the absence of new ischemic ECG changes and normal troponin levels both initially and after 2 hours, indicates low ACS risk.

The use of rapid diagnostic algorithms in emergency departments is an important adjunctive tool that helps quickly and accurately distinguish between high-risk and low-risk ACS patients. Successful implementation of these methods into daily clinical practice requires selecting the most appropriate scale depending on the primary clinical objective — either early exclusion of acute MI or identification of high-risk patients.

Currently, evidence-based guidelines most strongly support the use of the HEART or EDACS scales.