Key Points
- To determine whether noninvasive echocardiography can detect age-associated alterations in left ventricular chamber dimensions and systolic and diastolic function in female Fischer 344 rats.
- Evaluated female Fischer 344 (F344) rats at 4 months (young adult) and 30 months of age under 1.5% isoflurane sedation.
- Acquired 2D-guided M-mode, Doppler tissue, and pulsed-wave Doppler echocardiographic images across parasternal and apical views using 8-MHz, 10-MHz, or 15-MHz transducers.
- Resting left ventricular systolic function declined in 30-month-old versus 4-month-old rats, shown by lower ejection fraction (80 ± 9% vs. 89 ± 5%), fractional shortening (43 ± 9% vs. 54 ± 8%), and velocity of circumferential fiber shortening (2.43 ± 0.53 vs. 2.99 ± 0.50 circ/s).
- Diastolic function deteriorated with age, demonstrated by prolonged isovolumic relaxation time (25.0 ± 7.6 vs. 17.2 ± 4.4 ms) and decreased tissue Doppler peak E waves at both the septal and lateral mitral valve annuli.
Structured PICO
PPopulationFemale Fischer 344 (F344) rats (comparing 30-month-old vs 4-month-old young adults)
IInterventionAdvancing age (30 months old)
CComparatorYoung adult (4 months old)
OOutcomeEchocardiographic indexes of systolic and diastolic functionsurrogate
Advancing age in female F344 rats is associated with modest but significant declines in both systolic and diastolic LV function as assessed by echocardiography.