ABC | Volume 110, Nº4, April 2018

Original Article Winter et al High-intensity training after AMI Arq Bras Cardiol. 2018; 110(4):373-380 Table 2 – Between-group echocardiographic comparisons of left ventricular ejection fraction, end-diastolic diameter and end-systolic diameter Variable Group Mean ± SD p LVEF1 (%) CG 76.10 ± 6.89 0.368 CTG 73.67 ± 10.01 ITG 70.70 ± 8.15 LVEF 2 (%) CG 71.20 ± 6.44 0.981 CTG 71.89 ± 8.68 ITG 71.50 ± 7.53 EDD 1 (mm) CG 5.26 ± 0.80 0.103 CTG 6.50 ± 1.63 ITG 6.19 ± 1.30 EDD2 (mm) CG 6.20 ± 0.58 0.404 CTG 6.00 ± 1.15 ITG 6.00 ± 1.69 ESD1 (mm) CG 3.17 ± 0.70 0.308 CTG 3.83 ± 0.93 ITG 3.78 ± 1.40 ESD 2 (mm) CG 3.74 ± 0.75 0.709 CTG 4.19 ± 1.23 ITG 4.01 ± 1.46 LVEF1: left ventricular ejection fraction at first evaluation; LVEF2: left ventricular ejection fraction at second evaluation; p: p-value of LVEF between the two study days EDD1: end-diastolic diameter at first evaluation; EDD2: end-diastolic diameter at the second evaluation; ESD1: end-systolic diameter at first evaluation; ESD2: end‑systolic diameter at second evaluation; CG: control group, CTG: continuous training group; ITG: interval training group; One-factor ANOVA Table 1 – Within-group echocardiographic comparison of mean left ventricular ejection fraction, end-diastolic diameter and end-systolic diameter GROUP EDD1 EDD2 p ESD1 ESD2 p LVEF1 LVEF2 p CG 0.26 0.13 0.008* 0.17 0.74 0.120 76.10 71.20 0.112 CTG 0.50 0.58 0.741 0.83 0.19 0.422 73.67 71.89 0.579 ITG 0.19 0.88 0.153 0.78 0.01 0.510 70.70 71.50 0.792 CG: control group, CTG: continuous training group; ITG: interval training group; EDD1: end-diastolic diameter at first evaluation; EDD2: end-diastolic diameter at the second evaluation; ESD1: end-systolic diameter at first evaluation; ESD2: end-systolic diameter at second evaluation; LVEF1: left ventricular ejection fraction at first evaluation; LVEF2: left ventricular ejection fraction at second evaluation; p = p-value of LVEF between the two study days. Student’s t-test, * p < 0.05. 2) A worsening of EDDwas observed in the CG; 3) Both groups subjected to exercise showed significant differences in lactate production in the pre- versus post-training periods: ITG for the loads L12g and L13.5g, and CTG for L12g; 4) No difference was found between initial and final tests in the CG. The lack of difference in the pre- and post-training period between ITC and CTG indicates that high-intensity training, above LT, may be recommended for this sample. Current national and international guidelines 1,3 recommend a moderate-intensity, predominantly aerobic training (between the ventilatory thresholds, when evaluated by ergospirometry), i.e., below LT, to post-AMI patients. If these findings were extended to humans, these patients would benefit from this type of training, since it enables higher energy expenditure, better cardiovascular fitness and hence better control of cardiovascular risk factors. 11 Nevertheless, the same cannot be affirmed for animals with reduced LVEF, and further studies with the same study design are needed to assess the impact of a high-intensity training on ventricular remodeling. It is worth mentioning that an inadequate volume/intensity load of cardiac training or exercise may be assessed by changes in ventricular wall kinetics, 12 as evaluated by Neilan et al., 13 in a study with nonelite participants in the Boston marathon who were less trained. These findings were not observed in our trained groups, which implies that training density (relationship between volume and intensity) was well distributed. In addition, the training protocol proposed in this study may be applied to post-AMI patients with LVEF ≥ 50%, as long as a training/interval ratio of 1:1 for aerobic training and 1:2 for high-intensity interval training were respected. 375