Hypertensive heart disease is characterized by early development of hypertrophy and fibrosis that leads to heart failure (HF). HF develops in spontaneously hypertensive rats (SHR) after 18 months; however, it is not clear whether hypertrophy leads to altered cardiac performance at an earlier age in these rats. We studied cardiac performance in 10- to 11-month-old SHR and age-matched Wistar-Kyoto rats (WKY), using presssure-volume (PV) conductance catheter system to evaluate systolic and diastolic function in vivo at different preloads, including preload recruitable stroke work (PRSW), +dP/dt, and its relation to end-diastolic volume (+dP/dt-EDV) and preload-adjusted maximal power (PWRmax-EDV2) as well as the time constant of left ventricular pressure decay, tau (τ), as an index of relaxation. The slope of the end-diastolic pressure-volume relation (EDPVR) and the ex vivo PV relation, both indexes of stiffness, were also calculated for each heart, and the Doppler E/A ratio was determined. In addition, plasma samples were obtained to assess B-type natriuretic peptide levels (BNP). We found that PRSW was higher in SHR than in WKY (174.5±15.6 versus 92.6±18.9 mm Hg; P<0.01). +dP/dt and +dP/dt-EDV were also enhanced in SHR versus WKY (9125±662 versus 6633±392 mm Hg/sec, P<0.01, and 28.14±4.35 versus 12.7±2.8 mm Hg/s per μL, P<0.02). In addition, PWR-EDV2 was elevated in SHR (7.3±1.5 versus 3.1±0.6 mW/μL2). τ was prolonged in SHR (14.5±1 ms versus 10.8±0.8 for WKY, P<0.02) and EDPVR was significantly greater in SHR than in WKY (0.01±0.005 versus 0.004±0.001, P<0.05). The ex vivo pressure-volume relation was also steeper for SHR and the E/A ratio was 2.53±0.15 for SHR versus 1.67±0.08 for WKY (P<0.02). BNP was 45±2.5 pg/mL for SHR and 33.3±1.8 pg/mL for WKY (P<0.02). Taken together, these data suggest that at 10 to 11 months of age, before HF develops, SHR have increased systolic performance accompanied by delayed relaxation and increased diastolic stiffness.
|Original language||English (US)|
|Number of pages||6|
|State||Published - Feb 1 2003|
- Rats, spontaneously hypertensive
ASJC Scopus subject areas
- Internal Medicine