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Physiological Responses to Exercise in Pediatric Heart Transplant Recipients
被引:4
作者:
Bovard, Joshua M.
[1
]
De Souza, Astrid M.
[2
]
Harris, Kevin C.
[2
,3
]
Human, Derek G.
[2
,3
]
Hosking, Martin C. K.
[2
,3
]
Potts, James E.
[2
,3
]
Armstrong, Kathryn
[2
]
Sandor, George G. S.
[2
,3
]
Cote, Anita T.
[3
,4
]
机构:
[1] Univ British Columbia, Sch Kinesiol, Vancouver, BC, Canada
[2] BC Childrens Hosp, Childrens Heart Ctr, Vancouver, BC, Canada
[3] Univ British Columbia, Dept Pediat Cardiol, Vancouver, BC, Canada
[4] Trinity Western Univ, Sch Human Kinet, Langley, BC, Canada
基金:
加拿大自然科学与工程研究理事会;
关键词:
HEART TRANSPLANTATION;
STRESS ECHOCARDIOGRAPHY;
AEROBIC CAPACITY;
LEFT VENTRICULAR FUNCTION;
LEFT-VENTRICULAR MASS;
CARDIAC-OUTPUT;
STRESS ECHOCARDIOGRAPHY;
PROGRESSIVE EXERCISE;
ANATOMIC VALIDATION;
AMERICAN-SOCIETY;
UPRIGHT EXERCISE;
NORMAL-CHILDREN;
PERFORMANCE;
GROWTH;
D O I:
10.1249/MSS.0000000000001889
中图分类号:
G8 [体育];
学科分类号:
04 ;
0403 ;
摘要:
Introduction Pediatric heart transplant (HTx) recipients have reduced exercise capacity typically two-thirds of predicted values, the mechanisms of which are not fully understood. We sought to assess the cardiorespiratory responses to progressive exercise in HTx relative to controls matched for age, sex, body size, and work rate. Methods Fourteen HTx recipients and matched controls underwent exercise stress echocardiography on a semisupine cycle ergometer. Hemodynamics, left ventricular (LV) dimensions, and volumes were obtained and indexed to body surface area. Oxygen consumption (VO2) was measured, and arteriovenous oxygen difference was estimated using the Fick Principle. Results At rest, LV mass index (P = 0.03) and volumes (P < 0.001) were significantly smaller in HTx, whereas wall thickness (P < 0.01) and LV mass-to-volume ratio (P = 0.01) were greater. Differences in LV dimensions and stroke volume persisted throughout exercise, but the pattern of response was similar between groups as HR increased. As exercise progressed, heart rate and cardiac index increased to a lesser extent in HTx. Despite this, VO2 was similar (P = 0.82) at equivalent work rates as HTx had a greater change in arteriovenous oxygen difference (P < 0.01). Conclusions When matched for work rate, HTx had similar metabolic responses to controls despite having smaller LV chambers and an attenuated increase in hemodynamic responses. These findings suggest that HTx may increase peripheral O-2 extraction as a compensatory mechanism in response to reduced cardiovascular function.
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页码:850 / 857
页数:8
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