Is a patient with chest pain relieved by one dose of nitroglycerin (glyceryl trinitrate) after physical exertion, normal troponin levels, and ST segment depression on electrocardiogram (EKG) more likely to have chronic stable angina or non-ST elevation coronary syndrome?

Clinical Diagnosis: Non-ST Elevation Acute Coronary Syndrome (NSTE-ACS)

This patient most likely has non-ST elevation acute coronary syndrome (unstable angina or NSTEMI), not chronic stable angina, and requires urgent hospital admission with cardiology evaluation.

Critical Distinguishing Features

Why This is NSTE-ACS, Not Stable Angina

The presence of ST segment depression on ECG is the decisive factor that classifies this as an acute coronary syndrome rather than stable angina 1. The European Society of Cardiology explicitly warns that nitroglycerin response "can be misleading" and should not be used to distinguish cardiac from non-cardiac chest pain or to differentiate between stable and unstable presentations 2.

Key features supporting NSTE-ACS diagnosis:

• ST segment depression on ECG indicates active myocardial ischemia and places the patient in at least intermediate risk for adverse cardiac events, regardless of troponin status 1
• Normal troponins do not exclude unstable angina, which is part of the NSTE-ACS spectrum and carries substantial morbidity risk 3
• Relief with nitroglycerin is non-specific and occurs in both stable angina and acute coronary syndromes, as well as esophageal disorders 1, 3

Features That Would Suggest Stable Angina (Not Present Here)

Stable angina requires ALL of the following characteristics that are NOT met in this case 1, 3:

• Predictable pattern unchanged for at least 6 weeks 3
• No ECG changes during or after symptoms 1
• Consistently triggered only by a reproducible level of exertion 1, 3

Immediate Management Algorithm

Step 1: Emergency Evaluation (Within 10 Minutes)

• Admit to hospital immediately for continuous cardiac monitoring 2, 4
• Obtain serial troponins at 3-6 hour intervals, as initial normal values do not exclude evolving NSTEMI 2, 4
• Repeat 12-lead ECG to assess for dynamic ST changes or evolution to STEMI 2, 4

Step 2: Risk Stratification

This patient has intermediate-to-high risk features 1:

• ST segment depression (high-risk ECG finding) 1
• Exertional chest pain requiring nitroglycerin (intermediate risk) 1
• Age and gender considerations per clinical context 1

Step 3: Acute Medical Therapy

• Aspirin 162-325 mg (chewed, non-enteric) immediately unless contraindicated 4
• Continue nitroglycerin as needed for recurrent chest pain 4
• Initiate dual antiplatelet therapy and anticoagulation per NSTE-ACS protocols 1
• Beta-blockers unless contraindicated 1

Step 4: Early Invasive Strategy

Consider early angiography within 24 hours given the presence of ST depression, which indicates higher risk for adverse outcomes 1. The American College of Cardiology recommends early invasive evaluation for patients with ECG changes suggesting ischemia 1.

Common Pitfalls to Avoid

Pitfall #1: Relying on Nitroglycerin Response

Do not use nitroglycerin response as a diagnostic tool 2, 3. The European Society of Cardiology explicitly states this "can be misleading" because:

• Esophageal spasm also responds to nitroglycerin 3
• Both stable and unstable angina respond to nitroglycerin 1, 5
• Response typically occurs within 2 minutes regardless of underlying pathology 6

Pitfall #2: Dismissing Normal Troponins

Normal initial troponins do not exclude acute coronary syndrome 2, 4. Troponins may not rise for 3-6 hours after ischemic injury, and unstable angina by definition has normal biomarkers but still carries significant risk 1, 3.

Pitfall #3: Ignoring ST Depression

ST segment depression is a high-risk feature requiring urgent evaluation, even with symptom relief 1. This ECG finding indicates active ischemia and predicts higher rates of death and myocardial infarction 1.

Why Stable Angina is Excluded

Chronic stable angina would require 1, 3:

• Stable pattern for ≥6 weeks with no recent change in frequency, severity, or duration 3
• Normal or unchanged ECG during and after symptoms 1
• Predictable threshold for symptom onset with consistent exertion levels 1, 3

This patient's presentation with ST depression indicates active ischemia requiring urgent intervention, not a chronic stable pattern 1.

Patient Education and Follow-up

• Instruct the patient not to take more than 3 nitroglycerin doses before seeking emergency care 4
• Emphasize that complete symptom resolution does not exclude ongoing acute coronary syndrome 2
• Document exact nature of chest pain including location, radiation, duration, and associated symptoms 2