The dynamic and metabolic performance of @entity35 conditioned by a swimming program (CH) and hearts of sedentary @entity35 (SH) was studied in an isolated working @entity35 heart apparatus. Heart rate, filling pressure, and afterload were controlled or kept constant, and heart weights were comparable in both groups. When compared with SH, CH had @entity5691 and cardiac work. Atrial pacing at more rapid rates caused greater differences in these functions, and left ventricular pressure and maximal rate of pressure rise (dp/dt) became higher in CH than in SH. Atrial pacing was associated in CH with increased @entity26 consumption but in SH by increased @entity880 and @entity2388 production. When atrial filling pressure was elevated in order to perform ventricular function curves, CH showed greater dynamic responses than SH. There were also greater increments in @entity26 consumption, and the ratio of aerobic to anaerobic energy production was also higher in CH. The mechanism of increasing @entity26 consumption during stress in CH was mainly by improved coronary flow. In SH coronary flow did not change, but extraction of @entity26 from the perfusing fluid increased. The results indicate that in physically trained @entity35 the function of the heart as a pump is improved. These hearts have greater aerobic and mechanical reserve than hearts of sedentary animals. These effects appear to be at least partially due to improved mechanisms of @entity26 delivery.

The effect of physical training upon the mechanical and metabolic performance of the XXXX heart.

@entity5691 :: ('MESH:D016534', 'Disease') :: ['increased cardiac output'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen'] @entity880 :: ('MESH:D019344', 'Chemical') :: ['lactate'] @entity35 :: ('10116', 'Species') :: ['rat', 'rats'] @entity2388 :: ('MESH:D019289', 'Chemical') :: ['pyruvate']
@entity35 :: (10116,Species) :: ['rat']
