Volume 32, Nº 5, September and October 2019
DOI: http://www.dx.doi.org/10.5935/2359-4802.20190003
CASE REPORT
Left Ventricular Dyssynchrony in a Patient with Normal Perfusion and Stress-Induced Left Bundle Branch Block
Maria Gazzilli
Rexhep Durmo
Claudio Tinoco Mesquita
Raffaele Giubbini
Introduction
Left bundle branch block (LBBB) is na electrocardiographic abnormality that occurs in approximately 0.5–1.1% of all patients who undergo exercise testing.1 The diagnosis of complete LBBB is made with the 12-lead electrocardiogram (ECG) if all the following criteria are met: conduction originating above the atrioventricular node; a QRS duration of 120 milliseconds or more; predominantly upright complexes with broad-slurred R waves in leads I, V5, and V6; and a QS or RS pattern in V1 with a normal intrinsicoid deflection of 35 milliseconds.2
The precise mechanism and the prognostic significance of Exercise Induced-LBBB (EI-LBBB) remains unclear. EI-LBBB can be associated with coronary artery disease (CAD). However, in a group of patients, coronary arteries are normal.3 Several authors have attributed EILBBB to functional alterations of the conduction system mediated by autonomic influences in non-ischemic cases.4 We report a case of a 72-year-old female patient who developed LBBB during exercise stress testing and showed reversible abnormalities in cardiac contraction.
Keywords: Left Bundle Branch Block, Cardiac-Gated Single -Photon Emission Computer-Assisted Tomography; Myocardial Perfusion Imaging; Contraction Myocardial.
