ABC | Volume 110, Nº4, April 2018

Brief Communication Influence of Aerobic Training on The Mechanics of Ventricular Contraction After Acute Myocardial Infarction: A Pilot Study Giovani Luiz De Santi, Henrique Turin Moreira, Eduardo Elias Vieira de Carvalho, Júlio César Crescêncio, André Schmidt, José Antônio Marin-Neto, Lourenço Gallo-Júnior Divisão de Cardiologia - Departamento de Clínica Médica, Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto - Universidade de São Paulo, São Paulo, SP – Brazil Keywords Exercise; Rehabilitation; Myocardial Infarction; Myocardial Contraction; Stroke Volume; Magnetic Resonance Imaging. Mailing Address: Giovani Luiz De Santi • Av. Bandeirantes, 3900. Postal Code 14048-900, Monte Alegre, Ribeirão Preto, SP – Brazil. E-mail: giovanidesanti@cardiol.br, giovanidesanti@usp.br Manuscript received May 26, 2017, revised manuscript September 01, 2017, accepted October 19, 2017 DOI: 10.5935/abc.20180049 Abstract The study of myocardial contractility, based on the new anatomical concepts that govern cardiac mechanics, represents a promising strategy of analysis of myocardial adaptations related to physical training in the context of post-infarction. We investigated the influence of aerobic training on physical capacity and on the evaluation parameters of left ventricular contraction mechanics in patients with myocardial infarction. Thirty-one patients (55.1 ± 8.9 years) who had myocardial infarction in the anterior wall were prospectively investigated in three groups: interval training group (ITG) (n = 10), moderate training group (MTG) n = 10) and control group (CG) (n = 10). Before and after 12 weeks of clinical follow‑up, patients underwent cardiopulmonary exercise testing and cardiac magnetic resonance imaging. The trained groups performed supervised aerobic training on treadmill, in two different intensities. A statistically significant increase in peak oxygen uptake (VO 2 ) was observed in the ITG (19.2 ± 5.1 at 21.9 ± 5.6 ml/kg/min, p < 0.01) and in the MTG 18.8 ± 3.7 to 21.6 ± 4.5 ml/kg/min, p < 0.01). The GC did not present a statistically significant change in peak VO 2 . A statistically significant increase in radial strain (STRAD) was observed in the CG: basal STRAD (57.4 ± 16.6 to 84.1 ± 30.9%, p < 0.05), medial STRAD (57.8 ± 27, 9 to 74.3 ± 36.1%, p < 0.05) and apical STRAD (38.2 ± 26.0 to 52.4 ± 29.8%, p < 0.01). The trained groups did not present a statistically significant change of the radial strain. The present study points to a potential clinical application of the parameters of ventricular contraction mechanics analysis, especially radial strain, to discriminate post-infarction myocardial adaptations between patients submitted or not to aerobic training programs. Introduction The helical conformation of the myocardial fibers, anchored in the pulmonary and aortic rings, determines a heart rotation movement around its longitudinal axis and confers a maximum mechanical efficiency to the cardiac muscle. The magnitude and characteristics of the present phenomenon are sensitive to left ventricle segmental and global contractile alterations. 1,2 The parameters of myocardial deformation analysis and ventricular rotation represent a promising strategy for the study of cardiac contractility, allowing a reliable analysis of the left ventricular contraction dynamics, based on the new anatomical concepts that govern cardiac mechanics. 1,2 Aerobic physical training (AFT) after myocardial infarction (MI) improves cardiac output, peak oxygen uptake (VO 2 ), autonomic function and peripheral metabolism. Exercise programs, based on variables obtained through stress tests, are considered beneficial and safe for patients in the context of post-IM. 3 However, scientific papers that investigated the effects of TFA on post-MI ventricular remodeling process, particularly through cavitary volumes measurement, as well as by estimating cardiac function by left ventricle ejection fraction, in resting conditions, showed heterogeneous and inconsistent results. 4-7 Cardiac magnetic resonance allows an integrated analysis of myocardial function with the underlying pathology. Myocardial deformation curves, obtained by cardiac magnetic resonance imaging, represent tools capable of identifying initial or subclinical alterations, both in the segmental function and in the global function of the left ventricle. 8 The use of these new methodologies incorporated into cardiac magnetic resonance can have a potential application in the identification of incipient contractile alterations in the post-infarction myocardium related to physical training. In this sense, we do not find in the scientific literature, articles that have tried to document, by myocardial deformation parameters analysis and ventricular rotation, the effects of AFT in patients in the context of post-MI. It was investigated the influence of TFA, prescribed in two different intensities, on physical capacity and the analysis parameters of myocardial deformation and ventricular rotation in patients with a diagnosis of MI. Methods Patients Thirty patients, 55.1 ± 8.9 years, with the diagnosis of MI, were prospectively investigated after signing a informed 383