Cardiovascular Autonomic Dysfunction in Late-Stage Lyme Disease: A Comprehensive Autonomic Assessment.

Lyme disease, caused by Borrelia burgdorferi sensu lato, may lead to persistent complications, including autonomic nervous system dysfunction. Although postural orthostatic tachycardia syndrome is frequently associated with orthostatic intolerance in Lyme disease, broader autonomic impairment remains insufficiently characterized. This cross-sectional study included 324 participants: 233 patients with late-stage Lyme disease and 91 healthy controls. All participants underwent cardiovascular autonomic reflex testing, beat-to-beat heart rate variability analysis, baroreflex assessment, 24-hour Holter electrocardiography, and ambulatory blood pressure monitoring. Compared with controls, patients with Lyme disease demonstrated significantly higher rates of sympathetic and parasympathetic dysfunction (p<0.05). Heart rate variability spectral parameters, including very low frequency, low frequency, and high frequency components, were significantly reduced, while baroreflex sensitivity and baroreflex effectiveness index were also impaired (p<0.05). Holter monitoring additionally revealed reduced time-domain heart rate variability parameters and an elevated low-frequency/high-frequency ratio, suggesting relative sympathetic predominance in patients with Lyme disease (p<0.05). These findings support the presence of cardiovascular autonomic dysfunction in patients with late-stage Lyme disease and highlight the importance of comprehensive autonomic evaluation in this population. Keywords: Autonomic Dysfunction; Lyme disease; Heart rate variability; Neurocardiology.