Electrocardiographic Predictors of Cognitive Decline and Dementia: A Systematic Review

BACKGROUND: Markers of altered cardiac function might predict cognitive decline and dementia. OBJECTIVE: This systematic review aims to review the literature that examines the associations of various electrocardiogram (ECG) markers with cognitive decline and dementia in middle-aged and elderly populations. METHODS: We searched PubMed, Embase, and Web of Science through 1 July 2020 for literature and conducted a systematic literature review. We included studies examining the associations of ECG markers (e.g., left ventricular hypertrophy [LVH], spatial QRS-T angle, and QT prolongation) with cognitive function and dementia in adult populations regardless of study setting and design, but excluded studies examining atrial fibrillation and heart rate variability. RESULTS: Fourteen community-based cross-sectional and longitudinal studies were identified. ECG markers were investigated in association with dementia in four prospective studies, and with cognitive decline in ten prospective studies. ECG-assessed LVH was associated with dementia in one study while five heterogeneous prospective studies yielded inconsistent associations with cognitive decline. Regarding ventricular repolarization markers, spatial QRS-T angle was associated with cognitive decline in one study while another study found no association between QT prolongation and cognitive decline. High resting heart rate was associated with both dementia and cognitive decline in one study but not associated with dementia in another study. P-wave abnormality was significantly associated with incident dementia and cognitive decline in one prospective study. CONCLUSION: Some ECG markers were associated with incident dementia and cognitive decline. However, limited number of heterogeneous studies did not allow us to make firm conclusions. Further studies are needed.