OBJECTIVE: Eighty percent of patients infected by SARS-CoV-2 report persistence of one symptom beyond the 4-week convalescent period. Those with orthostatic tachycardia and orthostatic symptoms mimicking postural tachycardia syndrome, they are defined as Long-COVID POTS [LCP]. This case-control study investigated potential differences in autonomic cardiovascular regulation between LCP patients and healthy controls.
METHODS: Thirteen LCP and 16 healthy controls, all female subjects, were studied without medications. Continuous blood pressure and ECG were recorded during orthostatic stress test, respiratory sinus arrhythmia, and Valsalva maneuver. Time domain and power spectral analysis of heart rate [HR] and systolic blood pressure [SBP] variability were computed characterizing cardiac autonomic control and sympathetic peripheral vasoconstriction.
RESULTS: LCP had higher deltaHR (+ 40 ± 6 vs. + 21 ± 3 bpm, p = 0.004) and deltaSBP (+ 8 ± 4 vs. -1 ± 2 mmHg, p = 0.04) upon standing; 47% had impaired Valsalva maneuver ratio compared with 6.2% in controls (p = 0.01). Spectral analysis revealed that LCP had lower RMSSD (32.1 ± 4.6 vs. 48.9 ± 6.8 ms, p = 0.04) and HFRRI, both in absolute (349 ± 105 vs. 851 ± 253ms2, p = 0.03) and normalized units (32 ± 4 vs. 46 ± 4 n.u., p = 0.02). LFSBP was similar between groups.
CONCLUSIONS: LCP have reduced cardiovagal modulation, but normal sympathetic cardiac and vasoconstrictive functions. Impaired parasympathetic function may contribute to the pathogenesis of Long-COVID POTS syndrome.

Background: Vagal parasympathetic neurons are prone to degeneration in Parkinson\'s disease (PD). High-resolution ultrasound can precisely estimate the cross-sectional (CSA) area of peripheral nerves. Here, we tested the hypothesis that vagus CSA is reduced in PD. Methods: We included 56 healthy controls (HCs) and 63 patients with PD. Using a high-end ultrasound system equipped with a high-frequency transducer, five images were obtained of each nerve. The hypoechoic neuronal tissue was delineated offline with dedicated software and the CSA extracted. Results: In the initial PD vs. HC comparison, no statistically significant differences were observed in mean left vagus CSA (HC: 1.97 mm2, PD: 1.89 mm2, P = 0.36) nor in mean right vagus CSA (HC: 2.37 mm2, PD: 2.23 mm2, P = 0.17). The right vagus CSA was significantly larger than the left vagus CSA in both groups (P < 0.0001). Females were overrepresented in the HC group and presented with generally smaller vagus CSAs. Consequently, sex-adjusted CSA was significantly smaller for the right vagus nerve of the PD group (P = 0.041), but not for the left. Conclusion: A small but significant reduction in sex-adjusted right vagus CSA was observed in patients with PD. The left vagus CSA was not significantly reduced in patients with PD. Ultrasound may not be a suitable method to detecting vagal axonal loss in individual patients.

Achalasia is an uncommon disease that occurs due to inability of lower esophageal sphincter from relaxing, leading to dysphagia to liquids and solids. Clues to this diagnosis include: failed treatment with proton pump inhibitors, and changes on imaging studies including chest X-ray and barium esophagogram. Ultimately it is a diagnosis made on esophageal manometry. Swallow-induced syncope has been known in patients with achalasia for almost three centuries. Here we present the case of a patient with achalasia and a non-swallowing syncopal episode. To our knowledge and extensive search, there has been no report of a similar case.

BACKGROUND: Swallowing-induced syncope is rare and there are few case reports of it in the existing medical literature. Even rarer are instances involving young and healthy individuals, with no existing pre-conditions or apparent risk factors. Hence the value of such case reports in understanding the phenomenon better and potentially inferring patterns of practical interest is significant; here we describe an unusual case of a swallowing-induced syncope in a young, healthy, and active white man.
METHODS: A healthy 32-year-old white man experienced a syncopal episode following the ingestion of a cold carbonated beverage on a hot day. He rapidly recovered consciousness and save for mild lightheadedness all ill effects disappeared within minutes. On examination no concerns were detected and he was discharged, with the cause being ascribed to esophageal stimulation effected vagus nerve overactivation.
CONCLUSIONS: The suddenness and unpredictability of swallowing-induced syncope make it a potentially dangerous condition, with risks both to the patient as well as, depending on the context, others. However, it is poorly understood due to its infrequency. The present case report adds to the body of much needed evidence which should help facilitate an improved understanding of the phenomenon.

Chronic stress increases disease vulnerability factors including inflammation, a pathological characteristic potentially regulated by the gut microbiota. We checked the association between the gut microbiome and psychosocial stress in children/adolescents and investigated which stress parameter (negative versus positive emotion, self-report versus parental report, events versus emotions, biomarker cortisol versus parasympathetic activity) is the most relevant indicator herein.
Gut microbiome sequencing was completed in fecal samples from 93 Belgian 8-16y olds. Stress measures included negative events, negative emotions, emotional problems reported by parents, happiness, hair cortisol and heart rate variability (pnn50 parameter reflecting parasympathetic activity). Alpha diversity, beta diversity and linear discriminant analysis were the unadjusted analyses. Age, sex, socio-economic status, diet, physical activity, sleep and weight status were adjusted for via a redundancy analysis and differential abundance via zero-inflated negative binomial regression.
High stress as reflected by low pnn50 and more negative events were associated with a lower alpha diversity as indicated by the Simpson index. Happiness and pnn50 showed significant differences between high and low stress groups based on weighted UniFrac distance, and this remained significant after confounder adjustment. Adjusted and unadjusted taxonomic differences were also most pronounced for happiness and pnn50 being associated respectively with 24 OTU (=11.8% of bacterial counts) and 31 OTU (=13.0%). As a general pattern, high stress was associated with lower Firmicutes at the phylum level and higher Bacteroides, Parabacteroides, Rhodococcus, Methanobrevibacter and Roseburia but lower Phascolarctobacterium at genus level. Several genera gave conflicting results between different stress measures e.g. Ruminococcaceae UCG014, Tenericutes, Eubacterium coprostanoligenes, Prevotella 9 and Christensenellaceae R7. Differential results in preadolescents versus adolescents were also evident.
Even in this young healthy population, stress parameters were cross-sectionally associated with gut microbial composition but this relationship was instrument specific. Positive emotions and parasympathetic activity appeared the strongest parameters and should be integrated in future microbiota projects amongst other stress measures.

BACKGROUND: Vagally mediated atrioventricular block (AVB) may occur as a result of increased parasympathetic tone. This particular AVB is infrequently described in the literature, but its prevalence may be underestimated, as it may occur without recognition.
METHODS: We present a case of vagally mediated AVB that was identified by serial electrocardiography of a patient who presented to the emergency department with vomiting. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Vagally mediated AVB must be differentiated from paroxysmal, bradycardia-dependent AVB, which may progress to persistent AVB and require pacemaker placement. In an asymptomatic patient with vagally mediated AVB, pacemaker placement is contraindicated. However, if symptoms are clearly attributable to vagally mediated AVB, pacemaker placement may be reasonable.

This case highlights the rare diagnosis of Ogilvie\'s syndrome after minor surgery in a private hospital where facilities and expertise are generally sparse. It shows the importance of knowledge of the subject, proper assessment, accurate diagnosis, and early input from seniors is crucial to prevent ischemia and perforation of colon that carries high mortality.