IJCS | Volume 32, Nº5, September/October 2019

545 1. Tanaka H, Hiraishi M, Miyoshi T, Tsuji T, Kaneko A, Ryo K, et al. Exercise-induced left bundle branch block and subsequent mechanical left ventricularb dyssynchrony--resolvedwith pharmacological therapy. Cardiovasc Ultrasound. 2011 Feb 7;9(1):4. 2. Strauss DG, Selvester RH, Wagner GS. Defining left bundle branch block in the era of cardiac resynchronization therapy. Am J Cardiol. 2011;107(6):927-34. 3. Riera Jaume, Martinez G., Vega J, Gordillo E, Ferreira I, Pena C, et al. Exercise-Induced left Bundle Branch Block in Patients with coronary artery disease versus Patient with normal coronary arteries. Rev Esp Cardiol. 2002; 55(5):474-80. 4. Bozkut MF, Yildirir A, Kabakci G, Caner B. Exercise-induced Left bundle Branch Block during Tallium 201 myocardial perfusion Scintigraphy. A Case report. Angiology. 2001;52(2):145-8. 5. Higgins JP, Williams G, Nagel JS, Higgins JA. Left bundle braqnch block artifact on single photon emission computed tomography with technetiumTc 99m (tc-99m) agents: Mechanism andmethod to decrease false-positive interpretations. Am Heart J. 2006;15(2):619-26. 6. Gholamrezanezhad A, Mirpour S, Sarabandi F, Jazayeri B. Rate dependent left bundle branch block: The pattern of myocardial perfusion SPECT. Nucl Med Rev Cent East Eur. 2012;15(2):143-8. 7. Candell-Riera J, Oller-Martínez G, Pereztol-Valdés O, Castell-Conesa J, Aguadé-Bruix S, Soler-Peter M, et al. Usefulness of myocardial perfusion SPECT in patients with left bundle branch block and previous myocardial infarction. Heart. 2003;89(9):1039-42. 8. Falcão A, William C, Giorgi MC, Rodrigo I, Soares Jr J, Do Val R, et al. Myocardial blood flow assessment with 82rubidium-PET imaging in patients with left bundle branch block. Clinics. 2015;70(11):726-32. 9. Sillanma S, Lipponen J A, Tarvainen M P, Laitinen T. Relationships between electrical and mechanical dyssynchrony in patients with left bundle branch block and healthy controls. J Nucl Cardiol. 2018 Feb 8. [Epub ahead of print] 10. Hertzeanu H, Aron L, Shiner RJ, Kellermann J. Exercise dependent complete left bundle branch block. Eur Heart J. 1992;13(11):1447–51. References Gazzilli et al. Stress-induced left bundle branch block Int J Cardiovasc Sci. 2019;32(5):540-545 Case Report This is an open-access article distributed under the terms of the Creative Commons Attribution License dyssynchrony and patients with mechanical dyssynchrony associated to LBBB estimated by gated MPI have a worse outcome. Furthermore, Hertzeanu et al., 10 demonstrated that the onset of EI-LBBB at an HR of 120-125/min or lower is strongly correlated with the presence of occlusive CAD, compared to patients who develop EI-LBBB at an HR of 120-125/min or higher, which have a better prognosis. Considering that our patient had an EI-LBBB at an HR of 126 bpm, dyssynchrony and evidence of normal perfusion, we can assume that the medical therapy is effective and provides a good prognosis. This case demonstrates the usefulness of Gated SPECT to evaluate not only the perfusion data but also the synchronous contraction and motility of the left ventricle walls, as well as to provide important prognostic information on cardiac function to guide the clinical management. Conclusion Gated SPECT was useful in the follow-up of the patient with extensive CAD by providing elements on perfusion, synchrony and thickening and in the evaluation of CAD. Author contributions Conception and design of the research:Gazzilli M, Mesquita CT. Acquisition of data: Gazzilli M, Durmo R. Writing of themanuscript: Gazzilli M, Durmo R, Giubbini R. Critical revision of the manuscript for intellectual content: Mesquita CT, Giubbini R. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This study is not associated with any thesis or dissertation work. Ethics approval and consent to participate This article does not contain any studies with human participants or animals performed by any of the authors.