What is the workup for a patient with intermittent chest pain and a right bundle branch block (RBBB) on electrocardiogram (EKG)?

From the Guidelines

For a patient with intermittent chest pain and right bundle branch block (RBBB) on EKG, I recommend a comprehensive cardiac workup including a detailed history and physical examination, 12-lead EKG, cardiac biomarkers (troponin), and integration of the results to determine the likelihood of myocardial infarction (MI) or other cardiac conditions. According to the 2021 ESC guidelines for the management of acute coronary syndromes 1, the initial assessment should be based on the integration of clinical setting, 12-lead ECG, and cardiac troponin concentration.

The presence of RBBB in a patient with chest pain raises concern for underlying cardiac pathology, including coronary artery disease, pulmonary embolism, or cardiomyopathy. However, it is essential to note that more than 50% of patients presenting with acute chest pain and RBBB will ultimately be found to have a diagnosis other than MI 1.

The diagnostic algorithm should include:

• A detailed history and physical examination to identify high-risk features
• 12-lead EKG to assess for ST-elevation or depression, which can indicate STEMI or NSTE-ACS in the presence of RBBB
• Cardiac biomarkers, such as high-sensitivity troponin, to determine the likelihood of MI
• Echocardiogram to assess structural heart disease and ventricular function
• Stress testing (exercise or pharmacological) to evaluate for ischemia
• Possibly coronary CT angiography or invasive coronary angiography depending on risk stratification

Continuous cardiac monitoring for 24-48 hours may be warranted to detect arrhythmias. Treatment will depend on the underlying cause identified during workup, ranging from medical management with anti-anginal medications to revascularization procedures if significant coronary disease is found. The 2007 ACC/AHA guidelines for the management of patients with unstable angina/non-ST-elevation myocardial infarction also support the use of stress testing and cardiac biomarkers in the diagnosis and management of patients with suspected ACS 1.

From the Research

Initial Evaluation

• The initial goal in patients presenting with chest pain is to determine if the patient needs to be referred for further testing to rule in or out acute coronary syndrome and myocardial infarction 2, 3.
• A combination of age, sex, and type of chest pain can predict the likelihood of coronary artery disease as the cause of chest pain 3.
• The Marburg Heart Score and the INTERCHEST clinical decision rule can also help estimate ACS risk 3.

Electrocardiography

• Twelve-lead electrocardiography is typically the test of choice when looking for ST segment changes, new-onset left bundle branch block, presence of Q waves, and new-onset T wave inversions 2, 3.
• Right bundle branch block (RBBB) may be an isolated sign of acute myocardial infarction (AMI), and its presence in the context of acute chest pain should raise suspicion of critical proximal LAD coronary occlusion 4, 5.
• New-onset RBBB in the patient with typical STEMI in the context of ischemic symptoms should raise suspicion of critical proximal LAD coronary occlusion 5.

Diagnostic Considerations

• Other diagnoses to consider include chest wall pain/costochondritis, gastroesophageal reflux disease, and panic disorder/anxiety state 2, 3.
• Other less common but important diagnostic considerations include pneumonia, heart failure, pulmonary embolism, acute pericarditis, and acute thoracic aortic dissection 2, 3.
• The presence of RBBB in the context of chest pain should prompt a thorough evaluation for ACS, including cardiac biomarkers and imaging studies 4, 5, 6.

Management

• Patients with suspicion of ACS or changes on electrocardiography should be transported immediately to the emergency department 3.
• Those at low or intermediate risk of ACS can undergo exercise stress testing, coronary computed tomography angiography, or cardiac magnetic resonance imaging 3.
• New-onset RBBB in the patient with typical STEMI in the context of ischemic symptoms should prompt emergent coronary angiography and percutaneous coronary intervention 5.