Mind the Rhythm: ECG QT Dispersion and Cognition in Healthy Older Adults

Abstract

Background: Autonomic function has been linked to cognitive abilities in aging. Even in non-clinical states, a certain variability in heart rhythm regulation can be measured with QT dispersion (QTcD), an ECG marker of ventricular repolarization which has been linked to autonomic function and cardiovascular health. QTcD has been shown to be higher in individuals with mild cognitive impairment, and the highest in individuals with Alzheimer's disease. The goal of this study was to see if QTcD is associated with cognitive performance in healthy individuals. Methods: Sixty-three healthy inactive older adults (> 60 years) completed an extensive cognitive assessment (including inhibition, divided attention, updating, working memory, and processing speed), a physical fitness assessment, and underwent a resting ECG. Results: After controlling for age, sex, and education, QTcD significantly predicted global cognition (MoCA) scores (R 2 = 0.17, F (4.58) = 3.00, p < 0.03, β = −0.36). Exploratory analysis on the MoCA subcomponents revealed a significant association between the visual/executive subcomponent and QTcD (R 2 = 0.12, F (1.61) = 7.99, p < 0.01, β = −0.34). In individuals with high QTcD, QTcD values were linked to executive functions (R 2 = 0.37), processing speed (R 2 = 0.34), and dualtask performances (R 2 = 0.47). No significant associations were found within the low QTcD group. Conclusion: This study shows an association between ventricular repolarization (QTcD) and cognitive performance, in particular speed and executive functions, in healthy older adults. The results provide further support for linking autonomic heart regulation and age-related cognitive changes, and suggest that deviations on ECG, even within-normal range, could help detect early cognitive deficits.

Relationship between Alzheimer dementia and QT interval: A meta‐analysis

“…These findings are supported by a study of 63 healthy older adults, over 60 years of age, without dementia, in whom QT variability was significantly correlated with cognitive function as assessed by the Montreal Cognitive Assessment, executive composite score, non‐executive composite score, and the digit symbol substitution test. 38 …”

“…57,58 Fourth, an imbalance in the autonomic nervous system contributes to QT interval variability. 15,59 An important perspective is the concept summarized by Vrinceanu et al that degeneration in the prefrontal cortex, which is involved in cognition and autonomic function 38,60 produces simultaneous loss of both autonomic regulation and cognition, especially executive functions. 38 A "neurovisceral integration model" has been proposed in which cognition, autonomic function, and emotional regulation are interconnected and include the prefrontal cortex.…”

Associations of Cardiac Ventricular Repolarization with Serum Adhesion Molecules and Cognitive Function in Older Adults: The MIND-China Study

“…However, the PROSPER study targeted individuals who were aged 70–82 years and at high cardiovascular risk, which limits the generalizability of their findings to the general population. A small-scale population-based study of healthy inactive older adults from Canada suggested that higher QTc dispersion, a measure of ventricular repolarization reflecting autonomic cardiovascular dysregulation, was associated with lower global and executive function, indicating that ventricular repolarization may be a marker of cognitive performance prior to the onset of clinical CVDs or cognitive impairment [ 28 ]. By contrast, the Honolulu-Asia Aging Study of Japanese-American men found no association of prolonged QT interval in midlife with cognitive decline in late life [ 29 ].…”

Effect of pulmonary embolism location on electrocardiological parameters

“…When the difference between the alpha 0.05 and beta 0.02 groups was considered significant at 32.4%, the sample size was calculated as 54 for each group, with a total of 108 patients with the G Power program 6 .…”