Is troponin (cardiac biomarker) testing necessary for an elderly female patient with left chest pain, a history of cardiac issues and pulmonary embolism, on anticoagulation (blood thinners) therapy, with an electrocardiogram (EKG) showing Left Bundle Branch Block (LBBB)?

Troponin Testing in Elderly Female with Chest Pain, LBBB, and History of PE

Yes, troponin testing is absolutely necessary in this patient, but it should not delay immediate coronary angiography if she has ongoing symptoms with new or presumed new LBBB. The combination of chest pain and LBBB creates diagnostic uncertainty that requires both biomarker assessment and consideration for urgent invasive evaluation.

Why Troponin is Mandatory

• Measurement of cardiac troponin is mandatory in all patients with suspected acute coronary syndrome (ACS), regardless of ECG findings 1
• The 12-lead ECG and cardiac biomarkers such as troponin serve as the major ancillary testing tools for risk stratification in the emergency setting 1
• LBBB obscures ST-segment changes and makes ECG diagnosis of acute MI extremely difficult, necessitating reliance on troponin for diagnosis 2
• Elderly patients (≥75 years) often present with atypical symptoms and are at significant risk for complications with ACS, making objective biomarker assessment even more critical 1

Critical Diagnostic Challenges in This Patient

The LBBB Problem

• More than 50% of patients presenting with acute chest pain and LBBB will ultimately be found to have a diagnosis other than MI 1
• However, new or presumed new bundle-branch blocks can indicate a high-risk presentation in the emergency setting 1
• The sensitivity and specificity of clinical data, ECG, and biomarkers to predict acute coronary artery occlusion in the presence of LBBB are unclear 2

The PE History Complicates Matters

• Pulmonary embolism can present with chest pain, ECG changes, and elevated troponin levels, mimicking ACS 3, 4
• Elevated troponin occurs in 20.8% of patients with submassive PE due to right ventricular strain and myocardial injury 5
• Chest pain and ischemic ECG changes are frequently associated with myocardial injury resulting in increased troponin levels in PE patients 4
• One case series found that 68% of PE patients with chest pain and ECG changes had elevated troponin 4

Immediate Management Algorithm

Step 1: Draw Troponin Immediately BUT Do Not Wait for Results

• Obtain troponin at presentation, but do not wait for results to initiate reperfusion treatment if clinical suspicion for STEMI is high 1
• Serial troponin measurements should be planned at 6-12 hours from symptom onset to detect rising or falling patterns 6
• A single troponin measurement drawn less than 6 hours from symptom onset may miss myocardial injury and should never be used alone to exclude ACS 6

Step 2: Determine if LBBB is New or Old

• If the LBBB is new or presumed new with ongoing chest pain, treat as a STEMI equivalent and proceed immediately to coronary angiography 2
• Compare current ECG with previous records to establish whether LBBB is new 1
• New conduction abnormality with documented previous normal ECG is a high-risk feature supporting immediate coronary angiography 2

Step 3: Risk Stratify for Immediate Invasive Strategy

High-risk features warranting immediate angiography include 1:

• Prolonged ongoing rest pain (>20 minutes)
• Hemodynamic instability (hypotension, tachycardia)
• New or worsening heart failure signs
• Refractory ischemic symptoms despite optimal medical therapy (morphine, nitroglycerin, beta-blockers) 2

Step 4: Consider Alternative Diagnoses

Given her PE history and anticoagulation:

• Recurrent PE should remain in the differential, especially if she develops shock or syncope 3
• Obtain echocardiography to assess for right ventricular dysfunction (McConnell's sign suggests massive PE) 3
• Consider D-dimer and CT pulmonary angiography if clinical suspicion for PE is high 1

Common Pitfalls to Avoid

• Never delay coronary angiography for serial troponins in the setting of new LBBB with ongoing symptoms—this increases door-to-balloon time and worsens outcomes 2
• Do not assume LBBB is benign even if initial troponins are negative, as troponin may not rise until 6-12 hours after symptom onset 2, 6
• Do not dismiss the possibility of PE simply because troponin is elevated—elevated troponin can occur with both ACS and PE 4, 5
• Avoid relying solely on ECG interpretation in the presence of LBBB, as it is unreliable for detecting ischemia 1, 2

Anticoagulation Considerations

• Her existing anticoagulation for PE history does not preclude ACS—she may have both conditions
• If proceeding to coronary angiography, assess bleeding risk given her anticoagulation status
• Bivalirudin may be preferred over unfractionated heparin plus GP IIb/IIIa inhibitors during PCI in anticoagulated patients 1

Bottom Line for This Patient

Draw troponin immediately, initiate continuous cardiac monitoring, and if her LBBB is new or presumed new with ongoing symptoms, proceed directly to coronary angiography without waiting for troponin results 1, 2. The troponin will help with risk stratification and prognosis but should not delay definitive diagnosis via angiography in a high-risk presentation 1.