Search for: [Abstract = "Cardiac function of the control and Tgαq\*44 mice at the advanced stage of heart failure was measured in vivo using cine FLASH MRI \(Bruker 4,7 T\) at rest and under β\-adrenergic test \(dobutamine\). Based on cardiac cycle curve fallowing parameters were obtained Ejection Fraction, Cardiac Output, Stroke Volume, End Systolic Volume and End Diastolic Volume. For determination of appropriate doses of dobutamine in the i.p. injection during MRI protocol, 5 different doses were injected i.p. in the range from 0,15 mg\/kg to 20 mg\/kg.Low and high dobutamine doses that uncovered cardiac inotropic changes and gave reproducible results, were\: 0,5 and 5 mg\/kg. These doses were applied to the characterization of cardiac changes in Tgαq\*44 mice \(at 4, 8 and 12 months of age\) and in apoE\/LDLR\-\/\- mice at the advanced stage of atherosclerosis \(when fed standard or after two months of LCHP diet\).Results presented in this work confirmed previous data about resting cardiac function in Tgαq\*44 mice and extended them. There was\: increased filling rate in Tgαq\*44 mice at the age of 6 months and decreased ejection rate, filing rate and ejection fraction at the age of 16 months and uncovered lack of cardiac chronotropic reserve at the age of 8 months, then cardiac systolic and diastolic kinetic deterioration at the age of 12 months of age. Further changes involved decreased ejection fraction and stroke volume \(at the age of 15 months of age\), and then, at the decompensation stage of disease\(16\-18 months of age\)\: low and high dose of dobutamine uncovered cardiac ischemic response. Obtained results suggest profound influence of diastolic function at early stage in Tgαq\*44 mice that proceed contractility impairment and cardiac decompensation in course of the development of dilated cardiomyopathy and successive exhaustion of cardiac chronotropic and inotropic reserve, with secondary impairment of coronary perfusion that leads to a typical ischemic dobutamine response."]

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