Value of treadmill exercise testing in patients with complete bundle branch block.

Area of Science:

• Cardiology
• Diagnostic Imaging

Background:

• Bundle branch block, particularly complete left bundle branch block (CLBBB), can complicate the interpretation of standard diagnostic tests.
• Accurate noninvasive assessment of coronary artery disease (CAD) is crucial for patient management.

Purpose of the Study:

• To evaluate the diagnostic utility of exercise electrocardiography (E-ECG) in patients with complete bundle branch block (BBB).
• To determine the reliability of E-ECG in identifying coronary artery disease (CAD) in patients with CLBBB versus complete right bundle branch block (CRBBB).

Main Methods:

• Conducted exercise electrocardiography (E-ECG) and selective coronary arteriography in 24 consecutive patients with complete BBB.
• Defined positive E-ECG criteria as 1 mm J-point or ST-segment depression/elevation from baseline.
• Analyzed E-ECG results against coronary arteriography findings in CLBBB and CRBBB subgroups.

Main Results:

• In CLBBB patients (n=12), 11 had positive E-ECG, but only 1 had significant CAD, indicating a high false-positive rate.
• In CRBBB patients (n=12), 9 had positive E-ECG, with 8 having severe CAD, suggesting better diagnostic accuracy.
• E-ECG showed a high false-negative rate in CRBBB (1 of 3 negative tests).

Conclusions:

• E-ECG is unreliable for diagnosing CAD in patients with CLBBB due to a high incidence of false-positive results.
• E-ECG can provide useful information for the noninvasive evaluation of CAD in patients with CRBBB.