Sympathovagal equilibrium analysis in patients with COVID-19

Abstract

Introduction: With the increase of COVID-19 cases, an unusual manifestation for this type of virus began to appear anosmia and dysgeusia, which could indicate a neurologic alteration. In this context, it seems likely that subclinical manifestations of baroreflex involvement occur. The vegetative nervous system carries out the regulation of the baroreflex through the balance between sympathetic and parasympathetic activity. The objective of this study is to verify whether patients with COVID-19 present alteration of this equilibrium. Material and methods: Patients included had a confirmed diagnosis of COVID-19 admitted to the Internal Medicine Department of JB Iturraspe Hospital. A Holter recording was performed at rest for 5 minutes, determining the variables in the frequency domain using Fourier transform analysis. We excluded patients with diabetes, medicated with drugs that modify heart rate or with a history of irradiation to the neck. Results: 68 patients were studied. The mean age was 49±13 years. The median systolic blood pressure was 120 mmHg and the diastolic blood pressure 80 mmHg. The heart rate was 76±13 beats per minute and the median respiratory rate was 24 (16 to 40). Anosmia was observed in 22% and dysgeusia in 19% The variables in the frequency domain were: Low-frequency power (LF) 135.8ms2 (13.7-2861.7); High-frequency power (HF), 89.04ms2 (4.1-5234.4), LFnu 57.5±22.3, HFnu 43.1±22.6. LF:HF 2.1±2. 41.2% of the patients had a high LF:HF. Conclusions: LF and HF components can be obtained through frequency analysis. The relationship between these two elements would thus represent the sympathovagal balance and is expressed as the LF/HF ratio. We observed that 41.2% of the studied patients showed elevated LF/HF ratio. The 41.2% of the patients presented an increased LF:HF ratio, which could be interpreted as an alteration in autonomic function.