In a 50‑year‑old man with typical angina, a family history of premature sudden death, and a resting left bundle‑branch block, what is the most appropriate test to evaluate the coronary arteries?

Myocardial Perfusion Imaging with Pharmacologic Stress is the Most Appropriate Test

In this 50-year-old man with typical angina, left bundle branch block (LBBB), and a high-risk family history of premature sudden death, pharmacologic stress myocardial perfusion imaging (Option A) is the most appropriate test to assess the coronary arteries. 1, 2

Why LBBB Eliminates Exercise ECG and Requires Specific Testing

• Exercise ECG (Option C) is contraindicated and uninterpretable in patients with LBBB because the baseline ST-segment abnormalities from LBBB interfere with interpretation of ST-segment shifts during stress testing 3, 1, 2
• The American College of Cardiology and European Society of Cardiology explicitly state that exercise ECG should not be used for diagnostic purposes in patients with LBBB due to uninterpretable results 1
• LBBB renders the resting ECG uninterpretable for ischemia, eliminating exercise ECG as a diagnostic option 3, 1

Why Myocardial Perfusion Imaging is Superior to CT Angiography in This Case

• Pharmacologic stress myocardial perfusion imaging is specifically recommended by the American College of Cardiology and European Heart Journal for patients with uninterpretable ECGs such as LBBB 3, 1, 2
• The American College of Radiology recommends performing pharmacological stress myocardial perfusion imaging as the initial non-invasive test for patients with LBBB and typical angina 1
• CT angiography (Option B) is more appropriate for ruling out disease in low-to-intermediate risk patients, not for functional assessment in symptomatic high-risk patients like this case 1
• This patient has typical angina with a strong family history of premature sudden death (brother died at age 46), representing a high-risk phenotype that requires functional assessment, not just anatomic imaging 1

Technical Considerations for Myocardial Perfusion Imaging in LBBB

• Pharmacologic stress with dipyridamole, adenosine, or regadenoson is mandatory in LBBB patients because exercise myocardial perfusion imaging produces false-positive septal defects 3, 2
• Dipyridamole and adenosine are the preferred pharmacologic agents as they dilate normal coronary arteries more than obstructed ones, producing regional perfusion differences without artifacts 2
• Single-photon emission computed tomography (SPECT) with images obtained at rest and during pharmacologic stress is the recommended imaging technique 2

Why Calcium CT is Inadequate

• Calcium CT (Option D) has a specificity of only 40% for detecting significant coronary stenosis in symptomatic patients and is not recommended as a diagnostic test 3
• The American College of Cardiology does not recommend electron-beam computed tomography (calcium scoring) as a screening test for coronary artery disease due to poor specificity 3
• Calcium scoring provides anatomic information about plaque burden but does not assess functional significance of stenoses or ischemia 3

Clinical Algorithm for This High-Risk Patient

1. Proceed directly with pharmacologic stress myocardial perfusion imaging (dipyridamole or adenosine SPECT) as the first-line diagnostic test 1, 2
2. If perfusion imaging shows significant ischemia, proceed directly to invasive coronary angiography for definitive diagnosis and potential revascularization 1
3. Do not delay definitive evaluation in patients with typical angina, LBBB, and strong family history of premature sudden death 1

Important Caveats

• Dobutamine stress echocardiography is also not recommended in LBBB patients as it produces false-positive results in the septal region 2
• In cases of acute symptoms or hemodynamic instability, bypass non-invasive testing entirely and proceed directly to invasive coronary angiography 1
• The combination of typical angina symptoms, LBBB, and family history of sudden death at age 46 places this patient in a high-risk category requiring urgent functional assessment 3, 1