Time course and progression of pressure overload-induced cardiac hypertrophy in rats.

AIM: To study the time course and progression of pressure overload-induced left ventricular hypertrophy METHODS: Left ventricular hypertrophy was induced in rats by abdominal aorta constriction and assessed at different time points (10, 15, 20, 25, 35, and 45 days) after operation. RESULTS: The cardiac index (the ratio of heart weight to body weight) in aortic-banded animals was characterised by phasic changes when compared with the sham operated and the control animals. In aortic-banded rats the cardiac index rose sharply at days 10 and 15 after operation. This sharp increase was followed by a phase of slight increase (day 20), and then it again sharply increased (day 25). At the remaining time points (days 35 and 45) the cardiac index was significantly increased in comparison with that of the sham operated and the control animals but the increase diminished gradually. CONCLUSION: Our results suggest that left ventricular hypertrophy develops not in a linear but in a phasic way. Yet, the experimental model we used produced a relatively stable left ventricular hypertrophy.