Browsing by Subject "Autonomic nervous system dysfunction"

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    Application of Physiological Autonomic Activity Tracking GUI and Computational Algorithms for Measuring Persistent Vagal Nerve Dysfunction After Recovery from SARS‐CoV‐2 Infection
    (Wiley, 2022) Wilson, Damen A.; Nowak, Thomas; Gupta, Anita; McKinnon, Michael; Clements, Isaac; Everett, Thomas; Powley, Terry; Ward, Matthew; Medicine, School of Medicine
    Post‐Acute Sequelae of SARS‐CoV‐2 infection (PASC) is now recognized as a constellation of symptoms such as postural hypotension, anxiety, and “brain fog” in addition to autonomic nervous system dysfunction such as tachycardia and labile hypertension. Better quantification of these conditions, specifically, autonomic nervous system dysfunction, is desired for future diagnostics, treatment modalities, and gaining a further understanding of PASC. This research has led to application of a novel autonomic activity tracking algorithm and GUI suite from previous work, see Figure 1, to study the physiological autonomic activity in six patients who had recovered from acute SARS‐CoV‐2 infection a mean of six months prior but were still experiencing symptoms. By measuring skin sympathetic nervous activity (SKNA), heart rate variability, and the cutaneous electrogastrogram (EGG), all before and after a water meal challenge, the data was fed into a custom analysis pipeline, shown in Figure 1. Each of the PASC patients were compared to a mean response of 34 healthy controls, each undergoing a 20‐minute baseline recording and another 20‐minute recording after ingestion of an 8 oz water test meal. All six patients showed significantly abnormal heart rate variability on frequency domain analysis in predominantly the low frequency (LF) and very low frequency (VLF) bands, and less so in the high frequency (HF) band, suggesting sympathetic nerve dysfunction. Three patients showed a significant decrease in SKNA while two showed a significant increase. All patients showed an abnormal cutaneous EGG. As shown in Figure 2, the temporal responses of aSKNA, VLF, LF, HF, and EGG for the PASC patients revealed that on average they were statistically different (p<0.05) from the healthy controls’ responses respectively during 98.4%, 78.4%, 86.76%, 47.9%, and 86.1% of the 40‐minute time period in testing, 20 minutes of baseline and 20 minutes after ingestion. In conclusion, we are looking at the sympathetic, parasympathetic, and enteric nervous systems synced temporally for applications with classification and further stratification of PASC based on the temporal dynamics of their autonomic nervous system mediated coordination from digestion. This shows that SARS‐CoV02 infection appears to have a significant effect on sympathetic and parasympathetic autonomic nervous system function and may be responsible for the disturbances noted in PASC. This work provides the framework and example of use for further applications in autonomic disorder physiological response exploration and furthermore can be expanded to other areas of neuromodulation.
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    Heart Rate Variability Parameters Indicate Altered Autonomic Tone in Patients with COVID‐19
    (Wiley, 2022) Gruionu, Gabriel; Gupta, Anita; Rattin, Megan; Nowak, Thomas V.; Ward, Matthew; Everett, Thomas H.; Medicine, School of Medicine
    The COVID‐19 disease induces long term heart health complications and may induce autonomic nervous system dysfunction. Heart Rate Variability (HRV) is a measure of sympathetic (SNS) and parasympathetic (PNS) control of heart function. Recently, studies have shown that HRV analysis may be used as a predictor of COVID‐19 symptoms and correlates with progression of the disease. We aimed to uncover the interplay between SNS and PNS in hospitalized COVID‐19 patients at the time of admission and compare it with similar measurements in healthy patients (no comorbidities) and patients with cardiovascular disease. We hypothesized that COVID‐19 would induce autonomic dysfunction similar to patients with cardiovascular disease (CVD). ECG telemetry recordings of 30‐60 minutes in duration were acquired from patients that were admitted to Indiana University Health system hospitals for either COVID‐19 complications or for complications associated with cardiovascular disease (CVD) states (arrhythmia, heart failure, coronary artery disease). In addition, 20‐minute ECG Lead I recordings were obtained from healthy volunteers with no associated comorbidities. HRV parameters were calculated during sinus rhythm in the time, frequency, and nonlinear domains from the ECG telemetry recordings. The patient population was composed of 50 COVID‐19 patients (average age 63, range 26‐94), 32 healthy (average age 32.7, range 17‐69) and 49 patients with cardiovascular disease (average age 65.4, range 30‐88) as control groups. The COVID‐19 group had a higher percentage of patients with BMI>30 (obese) than the control groups (55% vs 36%). Also, the COVID‐19 and CVD patients had significantly higher heart rate and time‐domain HRV parameters (including SDRR, RMSSD, SDSD) and SD1 in the non‐linear domain when compared to healthy patients (88.8±53.0 and 87.9±55.2 vs 49.5±31.3, p<0.01). In the frequency domain, the LF/HF ratio was significantly lower in the COVID and CVD groups compared to healthy controls (0.5±0.76 and 0.55±0.50 vs 1.05±0.96, p<0.01). COVID‐19 patients have significant HRV alterations which suggest increased vagal tone than in healthy volunteers but similar to patients with severe cardiovascular disease comorbidities. Even though the COVID patients had an increased heart rate, the results of the HRV analysis indicate increased vagal tone which would support autonomic nervous system dysfunction in these patients.