Search

In dementia with Lewy bodies (DLB) neurodegenerative processaffects not only central, but also peripheral nervous structures,most frequently, neurons of autonomic ganglia, which mayunderlay autonomic dysfunction, including peripheral autonomicfailure. The purpose of this study was to analyze autonomicregulation of cardiac functions in patients with DLB with theassessment of the heart rhythm variability. Twenty three patientswith probable DLB were enrolled in the study. A control groupwas composed of healthy individuals comparable by sex and age.In DLB peripheral autonomic failure occurred significantlymore frequently. Orthostatic hypotension manifested at alreadyearly stages of the disease in half of the patients. Spectral analysisof the heart rhythm in patients with orthostatic hypotensionshowed relative predominance of high-frequency waves on thebackground of decreased power of low-frequency waves of the spectrum, which suggests decrease of sympathic influence on theheart rhythm. Relative parasympathicotonia combined withheart rhythm abnormalities seen as supraventricular extrasystols.Analysis of the influence on the heart rhythm of drugs used forthe treatment of cognitive and motor disorders showed that levodopadecreased the heart rhythm variability and parasympathictonus because of stimulation of cardiac adrenoreceptors.Anticholinesterase medications do not influence the heartrhythm variability, but can decrease severity of orthostatic hypotension.

Cardiac rhythm and its structure are indicators of the state of heart regulatory systems. Estimation of heart rhythm variability (HRV) makes it possible to detect cardiac autonomic regulatory impairments and to estimate their magnitude, by providing additional possibilities to examine autonomic disorders and to search for new differential diagnostic distinctions between Levy body dementia (LBD) and Parkinson's disease (PD).Objective: to analyze autonomic provision of cardiac performance in patients with LBD versus PD patients with and without dementia (PD+D and PD-D).Subjects and methods. The study enrolled 21 patients with probable LBD and 31 patients with PD (24 patients with PD-D and 7 with PD+D), who were matched for gender and age.Results and discussion. Resting heart rhythm analysis revealed no normal age-related abnormalities in patients with LBD as compared to those with PD+D who had a marked reduction in HRV. An orthostatic test in both patients with LBD and those with PD (mainly that with dementia) showed inadequate sympathetic effects on heart rhythm, which is suggestive of cardiac sympathetic dysregulation and favors the development of orthostatic hypotension. During the orthostatic test, the patients with LBD were found to have supraventricular premature contractions with the pulse being fixed, which were probably caused by the hypersensitivity of denervated receptors to humoral factors. As the denervation process became longer, receptor sensitivity was decreased, hence supraventricular premature beats and arterial hypertension were absent in the horizontal position in long ill patients with PD+D, in whom the adaptive properties were considerably lower.