[Association between sphericity, ventricular function and size of the infarction in rats].
BACKGROUND
The left ventricular (LV) sphericity is a factor associated with ventricular dysfunction, but it is not well-characterized in the experimental infarction model in rats.


OBJECTIVE
To analyze the association between the sphericity index (SI), the ventricular function and the infarcted area in an experimental rat model.


METHODS
Six months after the infarction (AMI, n=33) or simulated surgery (SHAM, n=18), the animals were submitted to an echocardiogram. The SI was obtained through the ratio between the diastolic areas at the LV long axis and the short axis.


RESULTS
The AMI group presented the lowest index of sphericity (1.32 x 0.23 vs 1.57 x 0.33; p=0.002), systolic function and relative thickness (0.13 x 0.003 vs 0.18 x 0.04; p<0.001) and the highest index of parietal stress (1.27 x 0.33 vs 0.88 x 0.25; p<0.001). There was a significant correlation between the infarct size and sphericity (p=0.046). At the linear regression analysis, the infarct size (p=0.014), but not the sphericity (p=0.683) and the parietal stress (p=0.176), was the predictive factor of the systolic function. Eccentric remodeling (p=0.011), but not sphericity (p=0.183) or the infarct size (p=0.101), was a predictive factor of parietal stress. Additionally, the infarct size (p=0.046), but not the eccentric remodeling (0.705), was a predictive factor of sphericity. The infarct size (p=0.015) and the parietal stress (p=0.011), but not the sphericity (p=0.705), were the predictors of eccentric remodeling.


CONCLUSIONS
The sphericity is associated, but it is not a determinant factor of parietal stress, of eccentric remodeling and ventricular systolic function in an experimental infarction model in rats.
Minicucci
Marcos F
MF
Faculdade de Medicina de Botucatu, UNESP, Botucatu, SP, Brasil.
Azevedo
Paula S
PS
Matsubara
Beatriz B
BB
Matsubara
Luiz S
LS
Paiva
Sergio A R
SA
Zornoff
Leonardo A M
LA
D000818:Animals; D004195:Disease Models, Animal; D006352:Heart Ventricles / Q000473:pathology; D016014:Linear Models; D008297:Male; D009203:Myocardial Infarction / Q000473:pathology* / Q000503:physiopathology; D051381:Rats; D013314:Stress, Mechanical; D016277:Ventricular Function, Left / Q000502:physiology*; D020257:Ventricular Remodeling / Q000502:physiology*