Negative long-term prognostic value of stress echocardiography in patients with left bundle branch block and without known coronary artery disease

Background Left bundle branch block (LBBB) is often associated with significant heart disease and is often the result of underlying coronary artery disease (CAD), myocardial injury, strain or hypertrophy. The role of stress echocardiography (SECHO) in a risk stratification of patients with LBBB has not been extensively documented. The Aim: The aim of our study was to assess the negative long-term prognostic value of SECHO in patients with left bundle branch block and without known coronary artery disease (CAD). Methods Our study consisted of 156 patients (mean age 63.1±9.5 years, female 95; 61.1%) with LBBB and without known CAD who were referred to the SECHO test for chest pain. All the patients had negative SECHO test according the Bruce protocol. Risk factors for CAD (diabetes, smoking, hypertension, high cholesterol and positive family history of CAD), functional capacity (Metabolic Equivalents - METs) and heart rate recovery (HRR) were recorded in all patients. Slow HRR was defined as ≤18 beats/min. Mean follow up of the patients was 114.6 ± 41.1 months for the occurrence of all-cause mortality and non-fatal myocardial infarction (MI). Results Out of 156 patients, 7 patients (4.5%) were lost to follow up so they were excluded from further analysis. During the follow-up period 22 out of 149 patients (14.8%) had an adverse event (14 deaths and 8 non-fatal MI). Negative predictive value of SECHO test was 85.2%. Using the Cox regression analysis, univariate predictors of adverse events were slow HRR (HR 3.452 [95% CI 1.266-9.414], p=0.016), age (HR 1.068 [95% CI 1.015-1.124], p=0.012) and achieved MET (HR 0.768 [95% CI 0.624-0.944], p=0.012) In the multivariate analysis slow HRR (HR 2.948 [95% CI 1.017-8.550], p=0.047) and achieved MET (HR 0.780 [95% CI 0.620-983], p=0.035) were independent predictors of adverse events. Using the Kaplan-Meier survival curve we see that the patients with slow HRR had much shorter event-free time (slow HRR 115.2 ± 14.4 months vs normal HRR test 163.1 ± 3.6 months, Log Rank 6.638, p=0.010). (Figure 1.) Conclusion SECHO test has excellent negative long-term prognostic value in patients with LBBB without known CAD, while patients with slow HRR and lower functional capacity have more pronounced risk for the occurrence of adverse events.