Diagnostic and prognostic accuracy of the exercise electrocardiogram in patients with preexisting right bundle branch...

The value of exercise testing in patients with right bundle branch block (RBBB) is uncertain. A retrospective review of 3609 patients who underwent exercise testing identified 163 (4.5%) with preexisting RBBB. After excluding those with coronary artery bypass graft(s), 133 patients remained and 48 (36%) had a prior myocardial infarction. Angiograms were available for 30 (23%) patients. After a mean follow-up of 33 +/- 23 months, seven patients had a fatal or nonfatal myocardial infarction. Twenty five (19%) patients had > or = 1 mm of non-upsloping ST depression in leads V5 or V6. With angiographic disease or previous myocardial infarction used as endpoints of coronary artery disease, the exercise test had a sensitivity of 27% (15/56), a specificity of 87% (67/77), and a predictive accuracy of 62% (82/133), (chi 2 = 4.04, p = 0.04). There were 24 deaths, a 10% annual mortality rate. Univariate analysis of clinical, exercise, and angiographic data revealed that nonsurvivors had a lower peak systolic blood pressure, a lower exercise capacity in METS, and a higher prevalence of coronary artery disease (p = 0.0001, p = 0.02, p = 0.03, respectively). Left ventricular ejection fraction and the amount of additional ST depression during exercise did not differ significantly (p = NS). Receiver operating characteristic curve analysis revealed that systolic blood pressure (area = 0.741, z = 5.22, p < 0.001) and exercise capacity (area = 0.66, z = 3.12, p = 0.009) were predictive of mortality, whereas additional ST depression during exercise (area = 0.588, z = 0.70, p = 0.24) was not.(ABSTRACT TRUNCATED AT 250 WORDS)