Dementia with Lewy bodies and autonomic regulation of cardiac functions

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.