Prediction of mortality in patients with right bundle branch block referred for pharmacologic stress echocardiography

Abstract

Right bundle branch block (RBBB) is independently associated with all-cause mortality in patients referred for noninvasive evaluation of coronary artery disease. However, further stratification of risk in these patients has not been specifically addressed. The aim of this study was to risk stratify patients with RBBB who were referred for stress echocardiography. The study population was comprised of 343 patients (267 men; age 66 +/- 9 years) with RBBB who underwent pharmacologic stress echocardiography (231 dipyridamole, 112 dobutamine) for evaluation of suspected or known coronary artery disease. Overall mortality was the only end point. Stress echocardiography was positive for ischemia in 109 patients (32%). During follow-up (38 +/- 32 months), 36 deaths occurred. Seventy-three patients underwent revascularization and were censored. Ischemia at stress echocardiography (hazard ratio [HR] 2.9, 95% confidence interval [CI] 1.5 to 5.5, p=0.002), left anterior fascicular block (LAFB) (HR 2.8, 95% CI 1.4 to 5.6, p = 0.002), age >65 years (HR 2.1, 95% CI 1.0 to 4.3, p=0.047), and wall motion score index at rest (HR 2.5, 95% CI 1.0 to 6.5, p=0.057) were multivariate predictors of mortality. On the basis of stress echocardiographic result and presence and/or absence of LAFB, 3 levels of risk were identified: (1) low-risk, in cases of no ischemia and no LAFB (49% of the entire study population); (2) intermediate-risk, in cases of ischemia or LAFB only; and (3) high-risk, in cases of ischemia and LAFB. Clinical data, electrocardiography at rest, and stress echocardiographic results can provide effective stratification of risk in patients with RBBB.