Nerve Conduction and Heart Rate variability in Patients with Hypothyroidism at a Tertiary Care Centre in Eastern Nepal

  • Shital Gupta Department of Basic and Clinical Physiology, BP Koirala Institute of Health Sciences, Dharan, Nepal
  • Rita Khadka Department of Basic and Clinical Physiology, BP Koirala Institute of Health Sciences, Dharan, Nepal
  • Dilip Thakur Department of Basic and Clinical Physiology, BP Koirala Institute of Health Sciences, Dharan, Nepal
  • Robin Maskey Department of Internal Medicine, BP Koirala Institute of Health Sciences, Dharan, Nepal
  • K D Mehta Department of Biochemistry, BP Koirala Institute of Health Sciences, Dharan, Nepal
  • Bishnu Hari Paudel Department of Basic and Clinical Physiology, BP Koirala Institute of Health Sciences, Dharan, Nepal
Keywords: hypothyroidism, heart rate variability, nerve conduction study

Abstract

Introduction: Thyroid hormone effects on many organs including central and peripheral nervous systems. However, these hormones do not affect all systems/organs to a similar extent. Thus, we conducted this study to explore the effect of thyroid hormones on somatic nervous system assessed by Nerve conduction study and cardiac autonomic activity assessed by heart rate variability.

Methods: The study included newly diagnosed hypothyroid patients and healthy controls. In all subjects NCS were performed in median, ulnar, tibial and sural nerves using Nihonkohden machine Cardiac autonomic control was assessed using Short-term Heart Rate Variability and parameters were analyzed by Time Domain and Frequency Domain methods.

Results: Both the groups were comparable in term of age, Body Mass Index, Pulse Rate, Systolic Blood Pressure and Diastolic Blood Pressure. Sensory parameters of NCS showed significant decrease in left median nerve SNAP amplitude (38.24±10.23 Vs 31.59±14.06, P=0.048) and nerve conduction velocity of bilateral median nerve in hypothyroid patients. In motor parameters of NCS, onset latencies of bilateral median nerves and right ulnar nerve were significantly increased in hypothyroid patients.  All Time Domain measures of HRV and Frequency Domain measures; LF Power, HF Power and Total Power were significantly decreased (P<0.05) in hypothyroid patients. These HRV parameters are indicators of parasympathetic activity.

Conclusions: In newly diagnosed hypothyroid patients, especially median nerve functions (both sensory and motor) and parasympathetic activity were decreased.  It reflects that in hypothyroidism both autonomic nervous system and other somatic nerves are not affected in a similar extent.

Keywords:  hypothyroidism; heart rate variability; nerve conduction study.

Author Biography

Rita Khadka, Department of Basic and Clinical Physiology, BP Koirala Institute of Health Sciences, Dharan, Nepal

Additional Professor, Department of Basic and Clinical Physiology

Published
2017-12-31
How to Cite
Gupta, S., Khadka, R., Thakur, D., Maskey, R., Mehta, K., & Paudel, B. (2017). Nerve Conduction and Heart Rate variability in Patients with Hypothyroidism at a Tertiary Care Centre in Eastern Nepal. Journal of Nepal Medical Association, 56(208), 407-11. Retrieved from http://jnma.com.np/jnma/index.php/jnma/article/view/3316
Section
Original Article