The course of heart failure development and mortality in rats with volume overload due to aorto-caval fistula

There are only few studies documenting the long-term outcome of aorto-caval fistula (ACF) in rats, a model of volume overload heart failure (HF). The aim of the present study was to describe HF-related morbidity and mortality, and to examine the relation between cardiac hypertrophy and survival.

Adult male Wistar rats underwent needle ACF or sham operation and 71 animals surviving the acute procedure with patent ACF were followed for 52 weeks.

By the end of the study, 72% of the ACF animals deceased and 82% developed HF signs. Of the HF rats, 65% died (median: 3 weeks after HF onset). Before death, body weight increased by 9% followed by a final drop. 28% ACF rats died suddenly, without preceding HF. Sudden death occurred earlier and in the rats with a trend to larger hearts (p = 0.07). In the whole ACF cohort, heart weight (heart weight/body weight ratio) was inversely associated with the length of survival (r = -0.51, p < 0.001).

The median survival of ACF Wistar rats is 43 weeks, longer than reported in other rat strains. Increased heart weight is associated with higher mortality and a significant number of animals die suddenly.