In a 76-year-old patient with acute chest pain and a normal initial 12-lead ECG, what is the appropriate work‑up?

Workup for Acute Chest Pain with Normal Initial ECG in a 76-Year-Old Patient

In a 76-year-old patient with acute chest pain and a normal initial ECG, you must immediately obtain high-sensitivity cardiac troponin, perform serial ECG monitoring every 15-30 minutes during the first hour if symptoms persist, and repeat troponin at 6-12 hours—a single normal ECG and single troponin cannot exclude acute coronary syndrome, as up to 40% of patients with evolving myocardial infarction present with a normal initial ECG. 1, 2

Immediate Diagnostic Testing

Serial Cardiac Biomarkers

• Measure high-sensitivity cardiac troponin (hs-cTn) immediately upon presentation and obtain results within 60 minutes of blood sampling. 2 This is the most sensitive and specific biomarker for myocardial injury. 2, 1
• A mandatory repeat troponin measurement must be performed 6-12 hours after symptom onset to detect rising or falling patterns indicative of myocardial injury. 2, 1, 3 A single early negative troponin is insufficient and cannot be used alone for disposition decisions. 1
• If available, use the ESC 0h/1h algorithm with blood sampling at presentation and 1 hour later, or alternatively the 0h/2h algorithm. 2 If these initial measurements are inconclusive and clinical suspicion remains, additional testing at 3 hours is recommended. 2

Serial ECG Monitoring

• Obtain repeat 12-lead ECGs every 15-30 minutes during the first hour if chest pain persists, recurs, or if any clinical change occurs (new dyspnea, diaphoresis, hemodynamic instability, arrhythmia). 1, 3 Symptom-driven timing takes absolute precedence over fixed scheduled intervals. 1
• Serial ECG monitoring increases detection of acute myocardial infarction by approximately 34% compared with a single initial ECG. 1 Up to one-third of patients with acute chest pain have a normal admission ECG, yet 5-40% of these patients develop evolving myocardial infarction. 2, 1, 4
• Consider additional ECG leads (V3R, V4R for right ventricular involvement; V7-V9 for posterior wall ischemia) if ongoing ischemia is suspected, as left circumflex or right coronary artery occlusions can be electrically silent on standard 12-lead ECG. 2, 3

Additional Diagnostic Studies

• Obtain a chest radiograph to evaluate for alternative cardiac, pulmonary, or thoracic causes of chest pain including aortic dissection, pulmonary embolism, pneumothorax, and mediastinal pathology. 2, 1
• Perform echocardiography to evaluate regional and global left ventricular function and rule in or rule out differential diagnoses. 2

Risk Stratification

High-Risk Features Requiring Immediate Admission

Admit to a monitored unit with continuous cardiac telemetry if ANY of the following are present: 1, 5

• Recurrent or persistent ischemic chest pain despite medical therapy
• Dynamic ECG changes on serial tracings
• Positive second troponin measurement or rising troponin pattern
• Hemodynamic instability (hypotension, shock)
• Life-threatening arrhythmias (ventricular tachycardia/fibrillation)
• New or worsening heart failure

Intermediate-Risk Features (Particularly Relevant for This 76-Year-Old)

• Prior history of ischemic heart disease 1
• Multiple coronary risk factors (hypertension, hyperlipidemia, smoking, diabetes) 1
• Advanced age (>70 years)—this patient should NOT be discharged without completing serial testing and risk stratification 1

Low-Risk Criteria

All of the following must be present: 2, 1

• No recurrent chest pain after 6-12 hours of observation
• Normal or unchanged ECG on serial testing
• Two consecutive negative troponin measurements (at 0 and 6-12 hours)
• Absence of any high-risk features

Management Based on Risk Stratification

For High-Risk Patients

• Admit to monitored unit with continuous rhythm monitoring 2
• Administer aspirin 150-300 mg oral loading dose (or 75-250 mg IV) immediately, followed by 75-100 mg daily maintenance dose 2, 1
• Add a P2Y12 receptor inhibitor (ticagrelor 180 mg loading dose then 90 mg twice daily, or prasugrel 60 mg loading dose then 10 mg daily if proceeding to PCI, or clopidogrel 300-600 mg loading dose then 75 mg daily if others unavailable) 2
• Initiate anticoagulation with low-molecular-weight heparin or unfractionated heparin 2, 1
• Provide beta-blockers and nitrates (sublingual or IV) for persistent or recurrent chest pain 2, 1
• Consider urgent coronary angiography when recurrent ischemia, elevated troponin, or hemodynamic instability is present 1, 5

For Intermediate-Risk Patients (This 76-Year-Old)

• Continue observation in a chest pain unit or emergency department with serial ECGs and troponins until the 6-12 hour window is completed 1, 5
• Initiate oral treatment including aspirin, clopidogrel (300 mg loading dose followed by 75 mg daily), beta-blockers, and possibly nitrates or calcium antagonists 2
• Perform either anatomic testing (coronary CT angiography) or functional testing (stress test, preferably with imaging) before discharge 2, 1
• For patients over 70 years, do NOT discharge without completing the above serial testing and risk stratification 1

For Low-Risk Patients (Only After Meeting All Low-Risk Criteria)

• Perform a stress test to confirm or establish diagnosis of coronary artery disease and assess risk for future events 2
• If significant ischemia occurs during stress testing (particularly at low workload), coronary angiography and revascularization should be considered 2
• If stress test is inconclusive, consider stress echocardiography or stress myocardial perfusion scintigraphy 2
• Arrange outpatient cardiology follow-up within 72 hours with clear instructions to return immediately for any recurrent chest pain 1

Critical Pitfalls to Avoid

• Never assume a normal admission ECG excludes acute coronary syndrome—this is the most dangerous error. 1, 4 Between 2-5% of patients with ACS are inappropriately discharged from the emergency department with a normal initial ECG. 4
• Never discharge without at least two serial troponin measurements; a single negative result drawn early may miss evolving myocardial injury. 1, 3
• Do not delay repeat ECGs while waiting for scheduled intervals if the patient's symptoms change—symptom-driven timing takes priority. 1, 3
• Do not discontinue low-molecular-weight heparin prematurely; continue until after the observational period when ECG changes are absent and second troponin is negative. 2
• Always compare current ECG with any prior ECGs when available to detect subtle changes. 1
• In patients over 70 years, never discharge based solely on initial negative testing—complete the full serial evaluation protocol. 1