Cardiac Autonomic Neuropathy in Newly Diagnosed Type-2 Diabetes Mellitus Patients with Special Reference to Left Ventricular Diastolic Dysfunction.

UNLABELLED

Cardiac autonomic neuropathy is one of the major risk factors for cardiovascular disease in people with Diabetes mellitus which is often underdiagnosed. It is defined as an impairment of cardiac autonomic nerve fibers in the cardiovascular system after excluding other causes. CAN occurs when sympathetic and parasympathetic cardiovascular fibers are affected which leads to neurohormonal compromise. Sympathetic overactivity stimulates the renin-angiotensin-aldosterone system and increases heart rate, stroke volume, and peripheral vascular resistance, thus contributing to left ventricular diastolic dysfunction.

MATERIAL

Our study was a hospital-based observational study carried out in 92 newly diagnosed type-2 DM patients during a one-year duration between June 1st, 2020, and May 31st, 2021.CAN was assessed by Cardiac autonomic reflex test described by Ewing and Clarke, and LVDD was assessed by 2D Echocardiography and Tissue Doppler Imaging. The statistical significance was fixed at 5% level of significance (p<0.05) for all analysis.

OBSERVATION

The mean age was 52.27 ± 9.72 years. Male: female ratio 1.71:1.The prevalence of CAN was 40.21% with early, definite and severe CAN were 20.65%, 16.30%, and 3.26% respectively. Majority of patients had abnormal heart rate response to deep breathing 25%.The least common response was blood pressure response to standing (2.17%).The patients with CAN had a statistically significant reduction of heart rate response to deep breathing (P value<0.001), valsalva maneuver (p value<0.001), standing after lying (p value 0.001), fall in systolic blood pressure after standing (p value<0.001) and less increase in diastolic blood pressure after sustained handgrip (p value<0.001) than the patient without CAN. CAN was more prevalent in the older age group (p value<0.001) and in patients with higher HbA1c (p value0.030). The prevalence of LVDD was 44.57%.The prevalence of LVDD was more in CAN present group (83.78%) than in CAN absent group (18.18%) with significant p value of <0.001. It shows a significant positive association between CAN and LVDD. The patients with CAN had impaired diastolic filling of left ventricle (Mean E/A ratio 0.92±1.14 versus 1.25±0.24, p value0.0400) and higher mean filling pressure (Mean E/é ratio 10.7±2.4 versus 8.9±2.6, p value0.001) compared with patients without CAN.

CONCLUSION

CAN and LVDD both are very common at the time of diagnosis of type 2 DM. We found a significant positive association between CAN and LVDD. We conclude that the presence of CAN can exert an effect on the impairment in left ventricular diastolic function which is additive to other risk factors of LVDD in type-2 DM.