Progressive QTc prolongation and reduced heart rate variability in dementia with Lewy bodies compared to Alzheimer's disease.

INTRODUCTION: Autonomic dysfunction (AuD) is a significant clinical challenge in patients with Dementia with Lewy Bodies (DLB). Manifestations of AuD such as orthostatic hypotension (OH) is associated with falls and decreased quality of life. Cardiac autonomic denervation is an early phenomenon in DLB and a potential contributor to OH. This retrospective study was undertaken to explore whether routine ECG tracings could be used to identify signs of autonomic dysfunction in DLB.

METHODS: 18 patients with DLB and 18 age-matched patients with Alzheimer's disease (AD) were included. ECGs and clinical data were analyzed retrospectively for heart rate variability (HRV) and QTc interval prolongation.

RESULTS: During an average of 10 years observation time (first to last ECG recording), the QTc interval increased in the DLB group, but not in the AD group. HRV was significantly lower at end of follow-up in the DLB group than in the AD group. DLB patients with OH had greater QTc prolongation.

CONCLUSION: Longitudinal ECG analysis indicates that signs of AuD in DLB are reflected on routine ECG tracings. If confirmed in larger cohorts, this could influence risk stratification and help direct preventive measures.