OBJECTIVE:This study aimed to investigate whether previous exercise training could prevent or attenuate acute cardiac alterations after myocardial infarction.METHODS:Female rats were submitted to swim training (1 h/day; 5 days/week) or allowed to remain sedentary for 8 weeks. Afterwards, they were randomly assigned to left coronary artery occlusion or sham surgery. After this procedure, the rats remained sedentary for one week until euthanasia. Cardiac structural and functional analyses were performed using Doppler echocardiography. The rats that had a moderate or large infarct size were included in the evaluations. The data (mean ± SEM) were analyzed using a two-way ANOVA model followed by Tukey's post-hoc test.RESULTS:After the surgery, no significant difference between the exercise and sedentary groups was observed in the left ventricular infarct sizes (34.58±3.04 vs. 37.59±3.07). In another group of rats evaluated with Evans blue 1 h after myocardial infarction, no siginificant difference in the area at risk was observed between the exercised and sedentary rats (49.73±1.52 vs. 45.48±3.49). The changes in the left ventricular fractional areas for the exercised and sedentary myocardial infarction groups (36±2% and 39±3%, respectively) were smaller than those for the exercise sham surgery (ES, 67±1%) and sedentary sham surgery (SS, 69±2%) groups. The E/A was higher in the sedentary myocardial infarction (4.4±0.3) and exercised myocardial infarction (5.5±0.3) rats than in the SS (2.4±0.1) and ES (2.2±0.1) rats.CONCLUSION:Previous swim training of female rats does not attenuate systolic and diastolic function alterations after myocardial infarction induced by left coronary artery occlusion, suggesting that cardioprotection cannot be provided by exercise training in this experimental model.

Background: There is little research in the efficacy and safety of a pharmaco-invasive strategy (PIS) in patients ≥75 years versus <75 years of age. We aimed to evaluate and compare the influence of advanced age on the risk of death and major adverse cardiac events (MACE) in patients undergoing PIS. Methods: Between January 2010 and November 2016, 14 municipal emergency rooms in São Paulo, Brazil, used full-dose tenecteplase to treat patients with STEMI as part of a pharmaco-invasive strategy for a local network implementation. Results: A total of 1852 patients undergoing PIS were evaluated, of which 160 (9%) were ≥75 years of age. Compared to patients <75 years, those ≥75 years were more often female, had lower body mass index, higher rates of hypertension; higher incidence of hypothyroidism, chronic renal failure, prior stroke, and diabetes. Compared to patients <75 years of age, in-hospital MACE and mortality were higher in patients with ≥75 years (6.5% versus 19.4%; p<0.001; and 4.0% versus 18.2%; p<0.001, respectively). Patients ≥75 years had higher rates of in-hospital major bleeding (2.7% versus 5.6%; p=0.04) and higher incidence of cardiogenic shock (7.0% versus 19.6%; p<0.001). By multivariable analysis, age ≥75 years was independent predictor of MACE (OR 3.57, 95% CI 1.72 to 7.42, p=0.001) and death (OR 2.07, 95% CI 1.12-3.82, p=0.020). Conclusion: In patients with ST-segment elevation myocardial infarction undergoing PIS, age ≥75 years was an independent factor that entailed a 3.5-fold higher MACE and 2-fold higher mortality rate compared to patients <75 years of age.

The present study aimed to analyze the effects of reperfusion of a distant coronary artery on cardiac function, the ultrastructure, and the molecular environment of the remote myocardium immediately after the completion of myocardial regional necrosis: delayed reperfusion (DR). Additionally, the effects of prior exercise on the outcomes of DR were investigated. Female rats with permanent occlusion or delayed reperfusion were randomly assigned to an exercise (swimming, 1 h/day, 5 days/week for 8 weeks) or sedentary protocol. Thus, the study included the following four groups: sedentary permanent occlusion, exercise permanent occlusion, sedentary delayed reperfusion, and exercise delayed reperfusion. The descending coronary artery was occluded for 1 h. Reperfusion was confirmed by contrast echocardiography, and the rats were observed for 4 weeks. Permanent occlusion and DR caused similar myocardial infarction sizes among the four groups. Interestingly, exercise significantly decreased the mortality rate. Delayed reperfusion resulted in significant benefits, including enhanced hemodynamics and papillary muscle contraction, as well as reduced apoptosis and collagen content. Protein calcium kinetics did not change. Meanwhile, developed tension and the Frank–Starling mechanism were enhanced, suggesting that calcium sensitivity was intensified in myofilaments. Remarkable remote myocardial benefits occurred after distant DR, and prior exercise intensified cardiac recovery. Our findings provide valuable information about DR. Our data might explain the better clinical outcomes in recent studies showing that late reperfusion could improve heart failure in patients with myocardial infarction. In conclusion, DR has remote myocardial benefits, including inotropism enhancement, pulmonary congestion reduction, and collagen and apoptosis attenuation, which are enhanced by prior exercise.