Exercise intolerance in volume overload heart failure is associated with low carotid body mediated chemoreflex drive
Andrade, David C.
Pontificia Universidad Catolica de Chile
Diaz-Jara, Esteban
Pontificia Universidad Catolica de Chile
Schwarz, Karla G.
Pontificia Universidad Catolica de Chile
Pereyra, Katherin V.
Pontificia Universidad Catolica de Chile
Diaz, Hugo S.
Pontificia Universidad Catolica de Chile
Marcus, Noah J.
Des Moines University
Ortiz, Fernando C.
Universidad Autonoma de Chile
Ortolani, Domiziana
Pontificia Universidad Catolica de Chile
Del Rio, Rodrigo
Journal
Scientific Reports
ISSN
2045-2322
Open Access
gold
Volume
11
Mounting an appropriate ventilatory response to exercise is crucial to meeting metabolic demands, and abnormal ventilatory responses may contribute to exercise-intolerance (EX-inT) in heart failure (HF) patients. We sought to determine if abnormal ventilatory chemoreflex control contributes to EX-inT in volume-overload HF rats. Cardiac function, hypercapnic (HCVR) and hypoxic (HVR) ventilatory responses, and exercise tolerance were assessed at the end of a 6 week exercise training program. At the conclusion of the training program, exercise tolerant HF rats (HF+EX-T) exhibited improvements in cardiac systolic function and reductions in HCVR, sympathetic tone, and arrhythmias. In contrast, HF rats that were exercise intolerant (HF+EX-inT) exhibited worse diastolic dysfunction, and showed no improvements in cardiac systolic function, HCVR, sympathetic tone, or arrhythmias at the conclusion of the training program. In addition, HF+EX-inT rats had impaired HVR which was associated with increased arrhythmia susceptibility and mortality during hypoxic challenges (similar to 60% survival). Finally, we observed that exercise tolerance in HF rats was related to carotid body (CB) function as CB ablation resulted in impaired exercise capacity in HF+EX-T rats. Our results indicate that: (i) exercise may have detrimental effects on cardiac function in HF-EX-inT, and (ii) loss of CB chemoreflex sensitivity contributes to EX-inT in HF.
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