Comparison of Cardiac Autonomic Function in Type 2 Spinocerebellar Ataxia With Normal Control Using Heart Rate Variability as a Tool: A Cross-Sectional Study in Eastern India

Background: Spinocerebellar ataxia (SCA) is a disease that refers to a category of inherited ataxias that are characterized by degenerative alterations in the cerebellum, pons, and spinocerebellar tracts. There are several different varieties of SCA and they are classified based on the mutant (altered) gene that causes the disease. Objective: To analyze the cardiovascular autonomic regulation in patients with type-2 spinocerebellar ataxia (SCA-2) from the heart rate variability (HRV) of 20 minutes resting electrocardiogram (ECG) and compare with the age and gender-matched controls. Materials and methods: HRV of 27 type-2 spinocerebellar ataxia patients was calculated offline from the resting ECG recording and compared with 23 age and gender-matched controls. The HRV was analyzed by HRV software module MLS 310. The frequency and time domain parameters were computed and compared. Result: Type-2 spinocerebellar ataxia patients have significantly low HRV and parasympathetic activity at rest compared to normal control. The total power in SCA-2 is 13491.63 ± 7660.77 ms(2) and the normal control is 21784.76 ± 11008.67 ms(2). High-frequency power (HF) which is a marker of parasympathetic activity in SCA-2 is 3823.1 ± 364 ms(2) and in normal control is 9006.1 ± 920.64 ms(2). The standard deviation of all NN intervals (SDNN), the square root of the mean-squared differences of successive intervals (RMSSD), spectral interval, and delta NN is significantly low in SCA-2. Conclusion: There is decreased parasympathetic tone and low HRV in SCA-2 as compared to normal controls.