Standard provocative manoeuvres in patients with and without left bundle branch block studied with myocardial SPECT

Background The objective of this study was to determine the prevalence of a nterior and septal defects in patients with left bundle branch block (LBBB) , and to assess the diagnostic accuracy of myocardial single photon emissio n computed tomography (SPECT) with technetium compounds in patients with an d without LBBB using standard provocative manoeuvres. Methods Five hundred and nine consecutive patients (456 without LBBB and 53 with LBBB) without previous infarction who had a coronary angiography perf ormed within < 3 months of the scintigraphic study were retrospectively eva luated. The same stress procedures were followed in all patients. (1) Only exercise when it was sufficient; and (2) exercise+simultaneous administrati on of dypiridamole if exercise was insufficient. Only reversible defects we re considered positive and <greater than or equal to>50% of coronary stenos is was considered significant. Results Prevalence of reversible anterior and septal defects was low (33% a nd 12%, respectively) in patients with LBBB. Although lower values of globa l sensitivity (81%) and specificity (73%) were obtained in these patients, there were no significant differences with respect to the patients without LBBB (89% and 86%, respectively). Specificity values for the diagnosis of s tenosis of left anterior descending (78%), left circumflex (96%) and right coronary artery (74%) in patients with LBBB were lower, but without signifi cant statistical differences with respect patients without LBBB (90%, 96% a nd 82%, respectively). Conclusions Myocardial SPECT with technetium compounds, using standard prov ocation manoeuvres, can be used in patients with LBBB with only a mild decr ease in diagnostic accuracy as compared to patients without LBBB. ((C) 2001 Lippincott Williams & Wilkins).