What is the best course of action for a patient with a history of atrial fibrillation (AFib), gastroesophageal reflux disease (GERD), anxiety, and coronary artery disease (CAD) presenting with chest pain and a heart rate of tachycardia?

Immediate Management of Chest Pain in High-Risk Patient

This patient requires immediate 12-lead ECG within 10 minutes, cardiac troponin measurement, and continuous cardiac monitoring to rule out acute coronary syndrome (ACS), given the high-risk profile with known CAD, AFib, and current chest pain. 1

Initial Assessment and Risk Stratification

This patient presents with multiple features that significantly increase the probability of ACS:

• History of CAD is one of the strongest predictors for acute myocardial infarction 1
• Heart rate of 90 bpm in a patient with known AFib requires assessment for rate control adequacy and potential ischemic triggers 1
• Age and prior cardiovascular disease substantially elevate ACS risk 1

Critical Time-Sensitive Actions

Obtain 12-lead ECG immediately (within 10 minutes) to assess for:

• ST-segment depression or elevation 1
• New T-wave inversions 1
• Transient ST-elevation 1
• Note: A normal ECG does NOT exclude ACS and occurs in 1-6% of ACS patients 1

If initial ECG is non-diagnostic, repeat ECG at 15-30 minute intervals during the first hour, especially if symptoms persist or recur 1

Cardiac Biomarker Strategy

Draw cardiac troponin immediately as the most sensitive and specific biomarker for NSTE-ACS:

• Troponin rises within a few hours of symptom onset 1
• A negative troponin on admission with more sensitive assays confers >95% negative predictive value 1
• However, a single negative troponin does NOT rule out ACS - serial measurements are required 1, 2

Serial troponin measurements should be obtained based on the assay sensitivity and time from symptom onset 1, 2

Differential Diagnosis Considerations

While cardiac causes are paramount given this patient's risk profile, the coexisting conditions require consideration:

GERD as Potential Mimic

• GERD is a common noncardiac cause of chest pain 1
• However, GERD and AFib have a bidirectional relationship - GERD can trigger AFib through autonomic stimulation, mechanical compression of the left atrium, and inflammatory mechanisms 3, 4, 5
• Do NOT attribute chest pain to GERD without first excluding ACS in this high-risk patient 1

Anxiety Considerations

• Anxiety is listed in the differential for chest pain 1
• Psychiatric causes should only be considered after definitive negative cardiac workup including troponins and stress testing or imaging 1
• This patient's known CAD makes anxiety an inappropriate initial diagnosis 1

Anticoagulation Status Verification

Verify the patient's anticoagulation regimen immediately:

• Patients with AFib and CAD may be on oral anticoagulation alone or combination therapy 6
• If on stable CAD with AFib (>12 months post-ACS/PCI), anticoagulation monotherapy is typically appropriate 6
• Adding aspirin to anticoagulation in stable CAD/AFib increases bleeding without clear additional protection 6

Imaging and Advanced Testing

If troponins are negative and ECG remains non-diagnostic but suspicion remains:

Consider stress testing or advanced imaging:

• Myocardial perfusion imaging (SPECT) has high sensitivity (90-100%) and negative predictive value (96-100%) for MI 1
• Coronary CT angiography can be cost-effective in low-risk patients, but this patient is NOT low-risk 1
• Chest X-ray is useful to exclude pulmonary causes and assess for cardiomegaly 1

Critical Pitfalls to Avoid

• Never dismiss chest pain as "just GERD" or "just anxiety" in a patient with known CAD without completing cardiac evaluation 1
• Do not rely on heart auscultation alone - absence of murmur or irregular rhythm does not exclude ACS 1
• Do not stop at a single normal troponin - serial measurements are essential 1, 2
• Recognize that AFib itself can mask ischemic ECG changes due to baseline rhythm abnormalities 1

Disposition Decision

If any of the following are present, admit for observation/telemetry:

• Positive or rising troponins 1
• Ischemic ECG changes 1
• Ongoing chest pain 1
• Hemodynamic instability 1

Only consider discharge if:

• Serial troponins remain negative 1
• ECGs show no ischemic changes 1
• Symptoms have completely resolved 1
• Appropriate outpatient follow-up with cardiology is arranged within 72 hours 1