Diabetic Cardiovascular Autonomic Neuropathy, the Handgrip Test and Ambulatory Blood Pressure Monitoring Parameters: Are There Any Diagnostic Implications?

Sympathetic Overactivity and Parasympathetic Impairment in Type 2 Diabetes: An Analysis of Cardiovascular Autonomic Functions

Background Cardiovascular autonomic dysregulation is a known complication of Type 2 diabetes mellitus (T2DM), characterized by dysregulation in heart rate (HR) and blood pressure (BP). These disruptions in cardiovascular autonomic control can significantly influence the morbidity and mortality associated with the disease. Objectives This study aims to investigate how T2DM affects cardiovascular autonomic functions by comparing responses in HR, BP, and specific autonomic function tests between a control group without diabetes and a study group with diabetes. The research questions focus on assessing HR variability, baroreflex sensitivity, and other autonomic parameters to determine the extent of cardiovascular autonomic dysregulation in diabetic patients.  Methods This cross-sectional study involved 200 adults, divided equally between a control group (n = 100) and a T2DM study group (n = 100). The exclusion criteria included cardiovascular diseases and renal impairment. Data collection involved assessing baseline characteristics such as age and BMI. Cardiovascular measures, including HR, systolic blood pressure (SBP), and diastolic blood pressure (DBP), were recorded after a five-minute rest. Autonomic function tests assessed sympathetic and parasympathetic responses, including the cold pressor test and the isometric hand grip exercise test. The statistical analysis was conducted using IBM SPSS Statistics for Windows, Version 25 (Released 2017; IBM Corp., Armonk, New York, United States), focusing on independent t-tests to compare between groups, considering p-values <0.05 as significant. Potential confounding variables like age and BMI were accounted for in the analysis to ensure robust findings  Results The study group showed a higher average BMI (28.95 ± 5.60) compared to the control group (26.50 ± 5.70) and an increased resting HR (74.20 ± 8.60 bpm vs. 69.30 ± 9.10 bpm). The SBP was slightly higher in the study group (115.00 ± 19.00 mmHg vs. 114.50 ± 8.90 mmHg), while the DBP was lower (71.50 ± 10.70 mmHg vs. 72.80 ± 6.70 mmHg). The autonomic function tests showed a smaller increase in SBP (106.80 ± 11.00 mmHg) and a larger increase in DBP (75.90 ± 8.30 mmHg) upon standing in the study group compared to controls. The cold pressor test indicated increased sympathetic activity in the study group, with significant rises in SBP (133.70 ± 10.30 mmHg) and DBP (83.40 ± 9.00 mmHg) compared to the control group (SBP: 114.31 ± 11.87 mmHg, DBP: 71.85 ± 8.67 mmHg). These findings demonstrate marked differences in cardiovascular autonomic responses between the groups. Conclusions This study demonstrates that T2DM significantly impacts cardiovascular autonomic functions, with diabetic patients showing altered HR and BP indicative of increased sympathetic and decreased parasympathetic activity. These autonomic dysfunctions may heighten cardiovascular risk in diabetic individuals. Our findings highlight the importance of monitoring and managing cardiovascular autonomic functions in diabetic patients to reduce their risk of cardiovascular complications. Further research should investigate the underlying mechanisms and the effectiveness of interventions to improve autonomic function in this population.

The handgrip test - A historical test for diabetic autonomic neuropathy or a marker of something else?

Cardiovascular autonomic neuropathy (CAN) is a frequent complication of diabetes mellitus and is associated with increased morbidity and mortality in patients with diabetes. Hence, early and correct diagnosis of CAN is crucial. Standard cardiovascular reflex rests (CARTs) have been the gold standard of CAN assessment. Originally, CARTs consisted of five reflex tests, but measuring diastolic blood pressure response to sustained handgrip exercise has no longer been suggested as an established clinical test. Increasing body of evidence suggests that isometric handgrip test should no longer be used for the evaluation of sympathetic dysfunction during cardiovascular autonomic neuropathy assessment in diabetic patients. The associations of isometric handgrip test results with parameters of hypertension and markers of hypertension-related target-organ damage in diabetic and non-diabetic individuals point toward its potential role as a screening tool to identify patients with high cardiovascular risk. The current review summarizes historical view of standard cardiovascular reflex tests and latest data on isometric handgrip test.

Effectiveness of yoga on Ewing's battery autonomic function test: cross-sectional study

INTRODUCTION

The cardiovascular autonomic functions can be tested by a Battery of five tests developed by Ewing and Clark in 1981 in Edinburgh. Yogic practices are immensely useful for physical, mental and spiritual development required for better autonomic function.

AIM AND OBJECTIVES

To assess the ANS (Autonomic function system) function with help of Ewing's Battery tests in yoga participants and healthy participants not practicing yoga.

MATERIALS AND METHODS

A cross-sectional study was conducted on 270 participants which were divided into two groups viz: 135 in healthy control (Group I) and 135 in yoga group (Group II). Subjects with informed consent between 40-50 years, were included in control (Group I) and those practicing yoga for past minimum 3 months were included in Group II. Anthropometric measurements were done and parasympathetic tests like Heart rate (HR) response to standing from the supine posture, to Valsalva maneuvers and to slow deep breathing were done. Also, sympathetic tests, Blood Pressure (BP) response to cold in cold pressor test (CPT), to sustained handgrip test and to standing from lying posture were carried out.

RESULTS

P value was found to be statically significant among yoga group as compared with healthy control group in all the sympathetic and parasympathetic tests except in CPT. As per the Ewing's criteria, normal, early, diseased and severe CAN (Cardiac autonomic neuropathy) in healthy controls findings were 11.11%, 58.51%, 37.03%, 17.77% and in yoga participants findings were 37.7%, 34.8%, 6.66% and 8.88% respectively. According to Bellavere's classification, maximum diseased CAN were found in healthy control as compared to yoga group. As per AIIMS (All India Institute of Medical Sciences) criteria, parasympathetic neuropathy was observed in 11.85% of the healthy controls and in 6.66% of the yoga group, and that maximum sympathetic neuropathy was observed in 11.11% of the healthy patients and only 3.7% of the yoga group.

CONCLUSION

More emphasis should be given on implementation of yoga from early ages at the institutional levels, hospital levels. Yoga practices will suffice and lead to improvement of unhealthy ANS condition. Overall, Yoga showed better ANS function than healthy control group.

Association between Polypharmacy and Cardiovascular Autonomic Function among Elderly Patients in an Urban Municipality Area of Kolkata, India: A Record-Based Cross-Sectional Study

We assessed the association between polypharmacy and cardiovascular autonomic function among community-dwelling elderly patients having chronic diseases. Three hundred and twenty-one patients from an urban municipality area of Kolkata, India were studied in August 2022. The anticholinergic burden and cardiac autonomic function (Valsalva ratio, orthostatic hypotension, change in diastolic blood pressure after an isometric exercise, and heart rate variability during expiration and inspiration) were evaluated. Binary logistic regression analysis was performed to find out the association of polypharmacy and total anticholinergic burden with cardiac autonomic neuropathy. A total of 305 patients (age, 68.9 ± 3.4; 65.9% male) were included. Of these patients, 81 (26.6%) were on polypharmacy. Out of these 81 patients, 42 patients were on ninety-eight potential inappropriate medications. The anticholinergic burden and the proportion of patients with cardiac autonomic neuropathy were significantly higher among patients who were on polypharmacy than those who were not (8.1 ± 2.3 vs. 2.3 ± 0.9; p = 0.03 and 56.8% vs. 44.6%; p = 0.01). The presence of polypharmacy and a total anticholinergic burden of > 3 was significantly associated with cardiac autonomic neuropathy (aOR, 2.66; 95% CI, 0.91−3.98 and aOR, 2.51; 95% CI, 0.99−3.52, respectively). Thus, polypharmacy was significantly associated with cardiac autonomic neuropathy among community-dwelling elderly patients.