Cardiovascular Autonomic Function Tests in Patients of Obsessive–Compulsive Disorder: A Cross-Sectional Study

Background: Patients with psychiatric disorders are at an increased risk of developing cardiovascular disease, reducing life expectancy. Autonomic dysfunction has been linked to this increased risk; many studies have found reductions in heart rate variability (HRV). Only a few studies have systematically explored the relationship between obsessive–compulsive disorder (OCD) and autonomic function, and they have found contradicting results. The present study is intended to explore comprehensive autonomic functions in OCD patients and compare them with healthy controls. Methods: A total of 18 OCD patients meeting Diagnostic and Statistical Manual of Mental Disorders - 5 (DSM-5) criteria were enrolled to undergo comprehensive autonomic function testing, and the results were compared with 25 age- and sex-matched healthy controls. Results: Time-domain parameters of HRV such as standard deviation of the RR intervals, coefficient of variance of RR intervals, standard deviation of differences between adjacent RR intervals, root square of the mean of the sum of the squares of differences between adjacent RR intervals, and percentage of number of RR interval differences ≥ 50 ms were significantly lower in OCD patients, indicating lesser parasympathetic tone. Frequency-domain parameters such as total power and very low frequency were significantly lower in OCD patients, indicating a significant decrease in autonomic tone. Nonlinear parameters such as dispersion of points perpendicular to the line of identity and dispersion of points along the line of identity were significantly lower in OCD patients, indicating altered vagal and sympathetic tone. In autonomic reactivity tests, the fall in systolic blood pressure during the lying to standing test and change in diastolic blood pressure during the cold pressor test were significantly altered in OCD patients, indicating abnormal sympathetic reactivity. There was no significant correlation between autonomic parameters and the severity of OCD. Conclusion: OCD is characterized by a decreased parasympathetic tone and abnormal sympathetic reactivity compared to normal controls.

Heart Rate Variability in Insulo-Opercular Epilepsy

Background: We aimed to evaluate heart rate variability (HRV) changes in insulo-opercular epilepsy (IOE) and after insulo-opercular surgery. Methods: We analyzed 5-min resting HRV of IOE patients before and after surgery. Patients’ SUDEP-7 risk inventory scores were also calculated. Results were compared with age- and sex-matched patients with temporal lobe epilepsy (TLE) and healthy individuals. Results: There were no differences in HRV measurements between IOE, TLE, and healthy control groups (and within each IOE group and TLE group) in preoperative and postoperative periods. In IOE patients, the SUDEP-7 score was positively correlated with pNN50 (percentage of successive RR intervals that differ by more than 50 ms) (p = 0.008) and RMSSD (root mean square of successive RR interval differences) (p = 0.019). We stratified IOE patients into those whose preoperative RMSSD values were below (Group 1a = 7) versus above (Group 1b = 9) a cut-off threshold of 31 ms (median value of a healthy population from a previous study). In group 1a, all HRV values significantly increased after surgery. In group 1b, time-domain parameters significantly decreased postoperatively. Conclusion: Our results suggest that in IOE, HRV may be either decreased in parasympathetic tone or increased globally in both sympathetic and parasympathetic tones. We found no evidence that insulo-opercular surgeries lead to major autonomic dysfunction when a good seizure outcome is reached. The increase in parasympathetic tone observed preoperatively may be of clinical concern, as it was positively correlated with the SUDEP-7 score.

Clinical use of the parasympathetic tone activity index as a measurement of postoperative analgaesia in dogs undergoing ovariohysterectomy

Introduction While the current tools to assess canine postoperative pain using physiological and behavioural parameters are reliable, an objective method such as the parasympathetic tone activity (PTA) index could improve postoperative care. The aim of the study was to determine the utility of the PTA index in assessing postoperative analgaesia. Material and Methods Thirty healthy bitches of different breeds were randomly allocated into three groups for analgaesic treatment: the paracetamol group (GPARAC, n = 10) received 15 mg/kg b.w., the carprofen group (GCARP, n = 10) 4 mg/kg b.w., and the meloxicam group (GMELOX, n = 10) 0.2 mg/kg b.w. for 48 h after surgery. GPARAC was medicated orally every 8 h, while GCARP and GMELOX were medicated intravenously every 24 h. The PTA index was used to measure the analgaesia–nociception balance 1 h before surgery (baseline), and at 1, 2, 4, 6, 8, 12, 16, 20, 24, 36, and 48 h after, at which times evaluation on the University of Melbourne Pain Scale (UMPS) was made. Results The baseline PTA index was 65 ± 8 for GPARAC, 65 ± 7 for GCARP, and 62 ± 5 for GMELOX. Postoperatively, it was 65 ± 9 for GPARAC, 63 ± 8 for GCARP, and 65 ± 8 for GMELOX. No statistically significant difference existed between baseline values or between values directly after treatments (P = 0.99 and P = 0.97, respectively). The PTA index showed a sensitivity of 40%, specificity of 98.46% and a negative predictive value of 99.07%. Conclusion Our findings suggest that the PTA index measures comfort and postoperative analgaesia objectively, since it showed a clinical relationship with the UMPS.

Minimum Dose of Levothyroxine Restored the Autonomic Balance on a Dalmatian Female Dog with Primary Hypothyroidism

Background: Hypothyroidism is an endocrine disease that leads to a reduction in the hormones thyroxine (T3) and triiodothyronine (T4), which therapy with levothyroxine restores the clinical signs related to the metabolic rate. Due to the influence of thyroid hormones on the heart, which is under the constant influence of the autonomic nervous system (ANS), dogs with hypothyroidism can develop bradycardia, arrhythmia, and dysautonomia. Heart rate variability (HRV) assesses autonomic modulation by the Holter method, which is scarce in dogs. We aimed to report the cardiac and autonomic effects of the primary hypothyroidism untreated and treated with levothyroxine in a canine case by Holter monitoring.Case: A 7-year-old female Dalmatian, weighing 36 kg, was referred for clinical evaluation due to apathy, weight gain, low hair quality, and lethargy. On physical examination, alopecic lesions on the hind limbs and tail, as well as bradycardia with a heart rate (HR) of 40-50 beats per minute (bpm) were observed, in addition to a 3/6 mitral murmur and 2/6 tricuspid murmur. Given the suspicion of thyroid gland disorder, the blood hormonal measurement revealed an increase in thyroid-stimulating hormone (TSH; 0.65 ng/mL) and a decrease in free T4 (0.11 ng/mL) and total T4 (0.44 ng/mL), confirming primary hypothyroidism. Therapy was started with a minimum dose of levothyroxine (0.913 mg, every 12 h), which clinical signs were restored in five months of treatment, with weight loss, hair growth, and active behavior. To assess the impact of untreated and treated hypothyroidism on the patient’s ANS, a Holter monitoring exam was performed for 24 h before and after therapy. Before treatment, the average HR was 75 bpm, and the HR<50 bpm occurred during 05 h 20 min 36 s. Still, 320 pause events (>2.0s), 1st-degree atrioventricular blocks (AVB), six ventricular ectopias events, and 2nd-degree sinoatrial block (SAB) were also observed. The ANS parasympathetic tone was significantly stimulated, highlighting bradycardia, arrhythmia, and dysautonomia. After five months of treatment with levothyroxine, the average HR was 89 bpm, and the HR<50 bpm occurred during 02 h 06 min 13 s. No ventricular pauses, blocks, or ectopias were observed, showing the stimulation of sympathetic tonus, which restored HR and ANS balance. Still, it was observed that the minimum levothyroxine dose corrected cardiac changes by increasing the low frequency (LF), decreasing the high frequency (HF), and, consequently, increasing the LF/HF ratio, normalizing the frequency conditions in HRV.Discussion: In the frequency index, HF indicates the vagal activity, whereas LF indicates both systems with parasympathetic predominance. Before treatment, the dog had a low LF/HF ratio (0.46), indicating dysautonomia with parasympathetic stimulation. After therapy, the conditions of bradycardia and functional cardiac capacity were corrected, restoring ANS, due to the serum recovery of thyroid hormones. This study reported the cardiac and autonomic effects of primary hypothyroidism untreated and treated with levothyroxine on a dog, that had intense bradycardia and abnormal stimulation of the parasympathetic tone, associated with episodes of 1st-degree AVB, ventricular ectopias, and 2nd-degree SAB. After therapy with a minimum dose of levothyroxine, there was a decrease in parasympathetic activity and an increase in sympathetic stimulus, correcting cardiac changes, and restoring the balance of ANS. As it is a simple, non-invasive, and safe tool that helps the clinician to understand cardiac autonomic modulation, it is recommended to adopt the Holter monitoring exam in cases of hypothyroidism cases to assess sympathetic-vagal balance and check potential cardiac risks.

Performance of the Parasympathetic Tone activity (PTA) index to predict changes in mean arterial pressure in anaesthetized horses with different health conditions

Background: The parasympathetic tone activity (PTA) index is based on heart rate variability recently and has been developed in animals to assess their relative parasympathetic tone and their analgesia nociception balance. The present study aimed to evaluate the variation of PTA in anaesthetized horses according to haemodynamic status and health conditions and to determine the performance of dynamic variations of PTA (∆PTA) to predict mean arterial pressure (MAP) variations.Results: Thirty-nine client-horses admitted to the Veterinary Campus of Lyon were anaesthetized for elective or emergency surgery and divided into “Colic” and “Elective” groups. During anaesthesia, dobutamine was administered as treatment of hypotension (MAP < 60 mmHg). No significant variation of PTA and MAP were detected immediately before and after the time of cutaneous incision. PTA increased 5 min before each hypotension (+15% in Elective and +11.4% in Colic group), conversely, PTA decreased 1 min after the administration of dobutamine (-12.7% in Elective and -9% in Colic group). Horses of the Colic group had lower PTA values than those in Elective group, whereas MAP didn’t differ between groups. Globally, to predict a 10% increase in MAP, ΔPTA performance was associated with: AUC ROC [95% CI] = 0.77 [0.70 to 0.83] (p<0.0001), with a sensitivity of 88.2% and a specificity of 57.7% for a threshold value of −1%. Besides, to predict a 10% decrease in MAP, ΔPTA performance was associated with: AUC ROC [95% CI] =0.80 [0.73 to 0.85] (p<0.0001), with a sensitivity of 62.5% and a specificity of 94.6% for a threshold value of 25%.Conclusions: The PTA index in anaesthetized horses appears to be influenced by the haemodynamic status and the health condition. The shift toward lower PTA values in colic horses may potentially reflects a sympathetic tone predominance. Of clinical significance, a PTA increase of >25% in 1 min showed an acceptable performance to predict a MAP decrease of >10% within 5 min. Even though these results require further evaluation, this index may thus help to predict potential autonomic dysfunctions in sick animals.

Performance of the Parasympathetic Tone activity (PTA) index to predict mean arterial pressure variations in anaesthetized horses with different health conditions

Background The parasympathetic tone activity (PTA) is an index based on heart rate variability recently developed in animals to assess their relative parasympathetic tone and their analgesia nociception balance. The present study aimed to evaluate the variation of PTA in anaesthetized horses according to haemodynamic status and health conditions and to determine the performance of dynamic variations of PTA (∆PTA) to predict mean arterial pressure (MAP) variations. Results Thirty-nine client-horses admitted to the Veterinary Campus of Lyon were anaesthetized for elective or emergency surgery and divided into “Colic” and “Elective” groups. During anaesthesia, dobutamine was administered as treatment of hypotension (MAP < 60 mmHg). No significant variation of PTA and MAP were detected at steady-state and following cutaneous incision. PTA increased before each hypotension (+ 15% in Elective and + 11.4% in Colic group), conversely, the administration of dobutamine was accompanied by a significant decrease in PTA (-12.7% in Elective and − 9% in Colic group). Horses of the Colic group had lower PTA values than those in Elective group, whereas MAP didn’t differ between groups. Globally, to predict a 10% increase in MAP, ΔPTA performance was associated with: AUC ROC [95% CI] = 0.77 [0.70 to 0.83] (p < 0.0001), with a sensitivity of 88.2% and a specificity of 57.7% for a threshold value of − 1%. Besides, to predict a 10% decrease in MAP, ΔPTA performance was associated with: AUC ROC [95% CI] = 0.80 [0.73 to 0.85] (p < 0.0001), with a sensitivity of 62.5% and a specificity of 94.6% for a threshold value of 25%. Conclusions The PTA index in anaesthetized horses appears to be influenced by the haemodynamic status and the health condition. The shift toward lower PTA values in colic horses may potentially reflect a sympathetic tone predominance. Of clinical significance, a PTA increase of > 25% in 1 min showed fair performance to predict a MAP decrease of > 10% within 5 min but a decrease in PTA was poorly specific to predict an increase in MAP. Even though these results require further evaluation, this index may thus help to predict potential autonomic dysfunctions in sick animals.

1066 Rapid Eye Movement (REM) Sleep Duration in Posttraumatic Stress Disorder (PTSD) Varies Dynamically and Directly Within the Individual With Indices of Sleep Consolidation and Parasympathetic Tone

Introduction Autonomic arousal in posttraumatic stress disorder (PTSD) has been associated with functional hypoactivation of the medial prefrontal cortex and hyperactivity of the amygdala which can directly affect sleep physiology including REM sleep. REM sleep has been associated with reduced fear conditioning; and PTSD has been associated with REM sleep fragmentation. A case report of a drug-free PTSD patient (Gupta MA,2019) who underwent 10 home sleep apnea tests (HSATs) observed a dynamic and inverse relation between REM sleep duration and indices of sympathetic activation during sleep and sleep fragmentation. This study has examined the relationship between REM sleep duration and sleep parameters related to sleep consolidation and parasympathetic tone in 17 PTSD patients who had completed at least 10 HSATs each. Methods 17 civilian PTSD patients (all female; mean±SD age: 47.59±10.52 years; 16 white) each completed 10 HSATs (WatchPAT200, Itamar)(over 1 to 45 months). The mean±SD initial PTSD Checklist for DSM-5 score was 49.24±13.08 (n=17), and Clinician Administered PTSD Scale for DSM-5 (CAPS-5) score was ≥55. Patients using benzodiazepines and/or narcotics were excluded. Results The overall mean±SD REM duration for all 10 visits (for 17x10 HSATs) was 84.40±8.65 minutes (range 69.13-96.97 min); the mean REM duration over the 10 HSATs correlated with other sleep indices as follows: sleep onset latency (Pearson r= -0.667, p=0.035); sleep efficiency (r=0.636, p=0.048); light sleep (NI+N2) percentage (r= -0.754, p=0.012); light sleep duration (r=0.692, p=0.027);deep sleep (N3) duration (r=0.635, p=0.048). Conclusion Over the 10 HSATs the average (n=17) REM sleep duration was directly related to indices of sleep consolidation (decreased sleep latency, increased sleep efficiency, increase in both light and deep sleep duration). The direct relation of REM sleep duration to duration of deep sleep, and inverse relation with light sleep percentage suggests REM sleep- related promotion of increased parasympathetic tone within the individual. Support None