title: Cardiac implications after myocardial infarction in rats previously undergoing physical exercise.
abstract: BACKGROUND
  Few studies have analyzed the cardiac effects of exercise prior to coronary occlusion.
  
  
  OBJECTIVE
  To evaluate the effects of myocardial infarction in rats undergoing physical exercise.
  
  
  METHODS
  Female rats underwent swimming exercise or were kept sedentary for eight weeks and were randomized to coronary occlusion or sham surgery, in one of the following four groups: Sedentary (S), exercise (E), Sedentary myocardial infarction (SMI) and Exercise myocardial infarction (EMI). After six weeks, their biometrics, Doppler echocardiography, hemodynamics and myocardial mechanics were analyzed.
  
  
  RESULTS
  No cardioprotection was observed in EMI animals and there was no difference in infarct size (%LV) between EMI (38.50 ± 4.60%) and SMI (36.58 ± 4.11%). Water content of the lung (%) of SMI (80 ± 0.59) and EMI (80 ± 0.57) was higher than that of S (78 ± 0.15) and E (78 ± 0.57) groups. Left ventricular systolic pressure (mmHg) (S: 130 ± 5, E: 118 ± 8; SMI: 91 ± 3; EMI: 98 ± 3) and the first positive time derivative (mmHg) positive pressure (S: 8216 ± 385; E: 8437 ± 572; SMI: 4674 ± 455; EMI: 5080 ± 412) of S and E were higher than those of SMI and EMI. The transverse fractional shortening (%) of SMI (27 ± 2) and EMI (25 ± 2) were similar and lower than that of E (65 ± 2) and S (69 ± 2). The E/A ratio was higher in SMI (5.14 ± 0.61) and EMI (4.73 ± 0.57) compared to S (2.96 ± 0.24) and E (2.83 ± 0 21). In studies of isolated papillary muscle, depression of the contractile capacity observed was similar to that of SMI and EMI, and there was no change in myocardial stiffness.
  
  
  CONCLUSIONS
  Previous training by swimming did not attenuate cardiac implications due to myocardial infarction.
authors.affiliation: Departamento de Medicina, UNIFESP, São Paulo, SP, Brasil. Eduveiga56@gmail.com
authors.forename: Eduardo Carvalho de Arruda
authors.initials: EC
authors.lastname: Veiga
authors.forename: Leslie Andrews
authors.initials: LA
authors.lastname: Portes
authors.forename: Danilo Sales
authors.initials: DS
authors.lastname: Bocalini
authors.forename: Ednei Luiz
authors.initials: EL
authors.lastname: Antonio
authors.forename: Alexandra Alberta dos
authors.initials: AA
authors.lastname: Santos
authors.forename: Marília Higuchi
authors.initials: MH
authors.lastname: Santos
authors.forename: Flavio André
authors.initials: FA
authors.lastname: Silva
authors.forename: Paulo José Ferreira
authors.initials: PJ
authors.lastname: Tucci
mesh_terms: D000818:Animals; D054059:Coronary Occlusion / Q000150:complications; D015150:Echocardiography, Doppler; D005260:Female; D009203:Myocardial Infarction / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D010210:Papillary Muscles / Q000503:physiopathology; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013550:Swimming / Q000502:physiology*; D018754:Ventricular Dysfunction / Q000503:physiopathology; D020257:Ventricular Remodeling / Q000502:physiology