TY - JOUR
T1 - Impact of exercise training on ventricular properties in a canine model of congestive heart failure
AU - Todaka, Koji
AU - Wang, Jie
AU - Yi, Geng Hua
AU - Knecht, Mathias
AU - Stennett, Richard
AU - Packer, Milton
AU - Burkhoff, Daniel
PY - 1997/3
Y1 - 1997/3
N2 - Exercise training improves functional class in patients with chronic heart failure (CHF) via effects on the periphery with no previously documented effect on intrinsic left ventricular (LV) properties. However, because methods used to evaluate in vivo LV function are limited, it is possible that some effects of exercise training on the failing heart have thus far eluded detection. Twelve dogs were instrumented for cardiac pacing and hemodynamic recordings. Hearts were paced rapidly for 4 wk. Six of the dogs received daily treadmill exercise (CHF(EX), 4.4 km/h, 2 h/day) concurrent with rapid pacing, while the other dogs remained sedentary (CHF(S)). Hemodynamic measurements taken in vivo at the end of 4 wk revealed relative preservation of maximum rate of pressure rise (2,540 ± 440 vs. 1,720 ± 300 mmHg/s, P < 0.05) and LV end-diastolic pressure (9 ± 5 vs. 19 ± 4 mmHg, P < 0.05) in CHF(EX) compared with CHF(S). The hearts were then isolated and cross perfused for in vitro measurement of isovolumic pressure- volume relations; these results were compared with those of six normal dogs (N). Systolic function was similarly depressed in both groups of pacing animals [end-systolic elastance (E(es)) values of 1.66 ± 0.47 in CHF(S), 1.77 ± 0.38 in CHF(EX), and 3.05 ± 0.81 mmHg/ml in N, with no changes in volume axis interceptors of the end-systolic pressure-volume relationship]. The diastolic myocardial stiffness constant, k, was elevated in CHF(S) and was normalized by exercise training (32 ± 3 in CHF(S), 21 ± 3 in CHF(EX), 20 ± 4 in N). Thus daily exercise training preserved in vivo hemodynamics during 4 wk of rapid cardiac pacing and was accompanied by a significant change in diastolic myocardial stiffness in vitro. These findings suggest that changes in heart function may contribute to the overall beneficial hemodynamic effects of exercise training in CHF by a significant effect on diastolic properties.
AB - Exercise training improves functional class in patients with chronic heart failure (CHF) via effects on the periphery with no previously documented effect on intrinsic left ventricular (LV) properties. However, because methods used to evaluate in vivo LV function are limited, it is possible that some effects of exercise training on the failing heart have thus far eluded detection. Twelve dogs were instrumented for cardiac pacing and hemodynamic recordings. Hearts were paced rapidly for 4 wk. Six of the dogs received daily treadmill exercise (CHF(EX), 4.4 km/h, 2 h/day) concurrent with rapid pacing, while the other dogs remained sedentary (CHF(S)). Hemodynamic measurements taken in vivo at the end of 4 wk revealed relative preservation of maximum rate of pressure rise (2,540 ± 440 vs. 1,720 ± 300 mmHg/s, P < 0.05) and LV end-diastolic pressure (9 ± 5 vs. 19 ± 4 mmHg, P < 0.05) in CHF(EX) compared with CHF(S). The hearts were then isolated and cross perfused for in vitro measurement of isovolumic pressure- volume relations; these results were compared with those of six normal dogs (N). Systolic function was similarly depressed in both groups of pacing animals [end-systolic elastance (E(es)) values of 1.66 ± 0.47 in CHF(S), 1.77 ± 0.38 in CHF(EX), and 3.05 ± 0.81 mmHg/ml in N, with no changes in volume axis interceptors of the end-systolic pressure-volume relationship]. The diastolic myocardial stiffness constant, k, was elevated in CHF(S) and was normalized by exercise training (32 ± 3 in CHF(S), 21 ± 3 in CHF(EX), 20 ± 4 in N). Thus daily exercise training preserved in vivo hemodynamics during 4 wk of rapid cardiac pacing and was accompanied by a significant change in diastolic myocardial stiffness in vitro. These findings suggest that changes in heart function may contribute to the overall beneficial hemodynamic effects of exercise training in CHF by a significant effect on diastolic properties.
KW - collagen
KW - maximal elastance
KW - myocardial oxygen consumption
KW - pressure-volume relationship
KW - relaxation
KW - stiffness constant
KW - stress-strain analysis
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U2 - 10.1152/ajpheart.1997.272.3.h1382
DO - 10.1152/ajpheart.1997.272.3.h1382
M3 - Article
C2 - 9087615
AN - SCOPUS:0030946596
SN - 0363-6135
VL - 272
SP - H1382-H1390
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 3 41-3
ER -