Prognostic value of exercise stress echocardiography in patients with left bundle branch block.

Background: The literature lacks studies about the prognostic value of exercise stress echocardiography (ESE) in patients with complete left bundle branch block (LBBB) of the bundle of His.

Objective: To assess the prognostic value of ESE in patients with LBBB.

Methods: This is a retrospective cohort that evaluated 135 patients with LBBB, from January 2001 to October 2009, of which 37.8% were men, mean age 63.6 ± 11.5 years submitted to ESE according to Bruce protocol on a treadmill. Cox regression was used, considering these outcomes: death from all causes and from cardiac events, defined as acute myocardial infarction (AMI), percutaneous angioplasty (PA), coronary artery bypass grafting (CABG) and death from cardiac causes.

Results: Positive ESE was observed in 42 patients (31%). The mean follow-up was 45.8 ± 4.7 months. During this period, there were 9 deaths from all causes and 9 cardiac events (3 deaths from cardiac causes, 3 myocardial infarctions, 2 PA and one CABG). The mortality rate from all causes during five years was 16.1% in the group with positive ESE and 2.5% in the group with negative test (p = 0.171), whereas the rate of cardiac events in the same period was 15.1% for the positive ESE and 1.6% in the group with negative test (p = 0.009).

Conclusion: ESE showed to be a predictor of cardiac events in patients with LBBB.