ABC | Volume 111, Nº4, Octuber 2018

Original Article Relationship of Electromechanical Dyssynchrony in Patients Submitted to CRT With LV Lead Implantation Guided by Gated Myocardial Perfusion Spect Erivelton Alessandro do Nascimento, 1,2 Christiane Cigagna Wiefels Reis, 2 Fernanda Baptista Ribeiro, 3 Christiane Rodrigues Alves, 2 Eduardo Nani Silva, 3 Mario Luiz Ribeiro, 3 Claudio Tinoco Mesquita 2 Instituto Estadual de Cardiologia Aloysio de Castro, 1 Rio de Janeiro, RJ - Brazil Programa de Pós-graduação em Ciências Cardiovasculares da Universidade Federal Fluminense (UFF), 2 Niterói, RJ - Brazil Hospital Universitário Antônio Pedro - Universidade Federal Fluminense, 3 Niterói, RJ – Brazil Mailing Address: Erivelton Alessandro do Nascimento • Rua Gil Ferreira, 182. Postal Code 27283-570, Jardim Primavera, Volta Redonda, RJ - Brazil E-mail: hpcrates7@gmail.com , hpcrates@cardiol.br Manuscript received March 19, 2017, revised manuscript February 05, 2018, accepted May 09, 2018 DOI: 10.5935/abc.20180159 Abstract Background: Heart failure (HF) affects more than 5million individuals in the United States, withmore than 1million hospital admissions per year. Cardiac resynchronization therapy (CRT) can benefit patients with advanced HF and prolonged QRS. A significant percentage of patients, however, does not respond to CRT. Electrical dyssynchrony isolated might not be a good predictor of response, and the last left ventricular (LV) segment to contract can influence the response. Objectives: To assess electromechanical dyssynchrony in CRT with LV lead implantation guided by GATED SPECT. Methods: This study included 15 patients with functional class II-IV HF and clinically optimized, ejection fraction of 35%, sinus rhythm, left bundle‑branch block, and QRS ≥ 120 ms. The patients underwent electrocardiography, answered the Minnesota Living with Heart Failure Questionnaire (MLHFQ), and underwent gated myocardial perfusion SPECT up to 4 weeks before CRT, being reassessed 6 months later. The primary analysis aimed at determining the proportion of patients with a reduction in QRS duration and favorable response to CRT, depending on concordance of the LV lead position, using chi-square test. The pre- and post-CRT variables were analyzed by use of Student t test, adopting the significance level of 5%. Results: We implanted 15 CRT devices, and 2 patients died during follow-up. The durations of the QRS (212 ms vs 136 ms) and the PR interval (179 ms vs 126 ms) were significantly reduced (p < 0.001). In 54% of the patients, the lead position was concordant with the maximal delay site. In the responder group, the lateral position was prevalent. The MLHFQ showed a significant improvement in quality of life (p < 0.0002). Conclusion: CRT determines improvement in the quality of life and in electrical synchronism. Electromechanical synchronism relates to response to CRT. Positioning the LV lead in the maximal delay site has limitations. (Arq Bras Cardiol. 2018; 111(4):607-615) Keywords: Heart Failure; Cardiac Resynchronization Therapy; Eletrodes,Implanted;, Stroke Volume; Radionuclide Imaging. Introduction Heart failure (HF) affects more than 5 million individuals in the United States. Approximately 550,000 new cases are diagnosed annually, and decompensated HF accounts for over 1 million hospital admissions per year. 1 Projections show that HF prevalence will increase by 46% from 2012 to 2030, resulting in more than 8 million individuals with HF aged 18 years and older. 2 As a consequence of this epidemiological transition, of the advances in healthcare and of population aging, the prevalence of coronary artery disease, systemic arterial hypertension, obesity and diabetes mellitus is increasing and will have a significant impact on HF incidence in developing countries. 3 Cardiac resynchronization therapy (CRT) has become an option to treat advanced symptomaticHFwith: (A) left ventricular dysfunction; (B) electrical dyssynchrony; and (C) optimized clinical therapy. The technique has shown a significant improvement in New York Heart Association functional class (NYHA FC) and in left ventricular ejection fraction (LVEF) of individuals with severe ventricular dysfunction and left bundle-branch block (LBBB). 4 However, a significant group of patients does not respond favorably to CRT. 5-7 Patients with coronary artery disease and previous acute myocardial infarction are less likely to respond, because of the presence of fibrosis. The selection criteria for CRT currently used do not seem ideal, because previous studies on CRT using those criteria have found a significant percentage of patients (20% to 40%) who did not benefit from the therapy. 6,7 Electrocardiogram has been used to detect patients with dyssynchrony due to the correlation of the QRS complex prolongation (electrical dyssynchrony) with the presence 607