Cardiorespiratory Fitness Mediates Cognitive Performance in Chronic Heart Failure Patients and Heart Transplant Recipients

We compared cognitive profiles in chronic heart failure patients (HF), heart transplant recipients (HT) and healthy controls (HC) and examined the relationship between cardiorespiratory fitness (V˙O_2peak), peak cardiac output (CO_peak) and cognitive performance. Stable HT patients (n = 11), HF patients (n = 11) and HC (n = 13) (61.5 ± 8.5 years) were recruited. Four cognitive composite scores targeting different cognitive functions were computed from neuropsychological tests: working memory, processing speed, executive functions and verbal memory. Processing speed and executive function scores were higher, which indicates lower performances in HF and HT compared to HC (p < 0.05). V˙O_2peak and first ventilatory threshold (VT₁) were lower in HF and HT vs. HC (p < 0.01). CO_peak was lower in HF vs. HT and HC (p < 0.01). Processing speed, executive function and verbal memory performances were correlated with V˙O_2peak, VT₁ and peak cardiac hemodynamics (p < 0.05). Mediation analyses showed that V˙O_2peak and VT₁ mediated the relationship between group and processing speed and executive function performances in HF and HT. CO_peak fully mediated executive function and processing speed performances in HF only. V˙O_2peak and CO_peak were related to cognitive performance in the entire sample. In addition, V˙O_2peak and VT₁ fully mediated the relationship between group and executive function and processing speed performances.