Abstract Body (Do not enter title and authors here): Significance: Individuals with heart failure (HF) have reduced vagal control, an indicator of autonomic nervous system function. Additionally, more than half of individuals with HF experience cognitive impairment. Vagal control is associated with increased activity of the prefrontal and sub-cortical executive regions, which are associated with cognitive function. We hypothesize that among individuals with HF, higher vagal control is associated with better cognitive functioning.
Methods: This is a secondary analysis using baseline pre-randomization data from an ongoing RCT conducted in adults with HF and mild cognitive impairment (MCI) (scores 15-26 on MoCA). High frequency power (hf-HRV) (Ln msec2), a measure of vagal control, was determined by averaging high frequency values for 5 minute segments. Participants completed measures from the NIH Toolbox Fluid Cognition Battery: 1) Flanker Inhibitory Control and Attention Test (attention and inhibitory control), 2) Pattern Comparison Test (processing speed), 3) List Sorting Working Memory Test (working memory), 4) Picture Sequence Memory Test (episodic memory), 5) Dimensional Change Card Sort Test (attention and cognitive flexibility). We conducted six separate linear regression models with HF-HRV as the predictor and the overall age-adjusted Fluid Composition Cognitive score and age-adjusted scores from each test as the outcomes, controlling for sex and education.
Results: The average age of participants (n=54) was 72 years (SD = 11.2). Most (77%) were White and 38% were female. Higher HF-HRV was associated with higher Fluid Cognition Composite score (β = 0.02, 95% CI = 0.01, 0.03, p = .01), higher scores on the Picture Sequence Memory Test (β = 0.02, 95% CI = 0.01, 0.03, p = .001) and the Dimensional Change Card Sort Test (β = 0.02, 95% CI = 0.00, 0.04, p = .03), but was not associated with the other tests. After Bonferroni correction, the Fluid Cognition Composite score (p = .05) and Picture Sequency Memory Test (p = .03) remained significant. There were no associations between sex or education with overall cognitive score or scores on any of the tests.
Conclusions: Among patients with HF and MCI, higher vagal control was associated with better cognitive functioning. While decreased autonomic function might contribute to the prevalence of cognitive impairment in patients with HF, there is variability in vagal function among patients with HF. Higher vagal control is beneficial for episodic memory.