Experimental model for heart failure in rats--induction and diagnosis.

Background: Clinical heart failure is generally preceded by hypertrophy. Many animal models (e. g. toxic heart failure models) do not consider this hypertrophy. We set out to develop a heart failure model in rats by inducing pressure-overload hypertrophy.

Methods: We induced coarctation of the aortic arch with a tantalum clip (0.35 mm internal diameter) In 3-week-old rats (n=17). Starting at seven weeks postoperatively, we measured ejection fraction (EF), fractional shortening (FS), end-systolic (LVESD) and end-diastolic (LVEDD) left ventricular dimensions by echocardiography each week. Heart, lung, and liver specimens were analyzed histopathologically at least eleven weeks after the operation.

Results: Contractile function was significantly decreased in hearts from animals with aortic banding (EF: 45+/-5% vs. 73+/-5%, p<0.01; FS: 20+/-3% vs. 35+/-5%, p<0.01). At the same time, left ventricles were dilated (LVEDD: 9.1+/-0.6 mm vs. 7.4+/-0.5 mm; LVESD: 7.3+/-0.6 mm vs. 4.8+/-0.4 mm, p<0.01). These observations were associated with clinical and histopathological changes characteristic for chronic left heart failure.

Conclusions: Placing a tantalum clip around the aortic arch in 3-week-old rats consistently induces left ventricular decrease in contractile function and dilatation after eleven weeks.