Study of cardiac autonomic function in drug-naïve, newly diagnosed epilepsy patients.
BACKGROUND
Epilepsy is associated with ictal autonomic dysfunction which may extend into the inter-ictal period. Antiepileptic drugs have often been blamed for cardiac autonomic dysfunction in epilepsy patients. In this study we have investigated cardiac autonomic parameters in order to evaluate autonomic functions of drug-naïve epilepsy patients.


METHODS
Twenty drug-naïve patients (15 males and 5 females) with epilepsy, and an equal number of age and gender matched controls, were evaluated for short-term resting heart rate variability and conventional cardiovascular autonomic measurements.


RESULTS
The mean age of patients was 29.30 +/- 9.80 yrs (17-55 yrs), mean age at seizure onset was 19.70 +/- 9.15 yrs (3-40 yrs) and mean length of time since last seizure was 5.60 +/- 7.00 days (1-30 days). While there was no difference in the resting heart rate or conventional autonomic test parameters, time domain heart rate variability measurements showed a decreased percentage of R-R intervals of less than 50 ms and root mean square of R-R intervals in patients, when compared to controls. Frequency domain parameters showed a decreased total power (patients: 1,796.58 +/- 1,052.45 ms2; controls: 2,934.23 +/- 1,767.06 ms2, p = 0.008). Parameters indicative of decreased vagal tone, i.e. decreased high frequency power and increased low to high frequency ratio (patients: 1.69 +/- 0.94; controls: 1.14 +/- 0.64, p = 0.045), were observed among patients compared to controls.


CONCLUSIONS
Subtle but definite cardiac autonomic dysfunction, especially in vagal tone, was identified in drug-naïve, new-onset epilepsy patients. Seizures can cause long-term and often progressive cardiac autonomic dysfunction which may be independent of concomitant antiepileptic drugs.
Mativo
Peter
P
Department of Medicine, Aga Khan University, Nairobi, Kenya.
Anjum
Javad
J
Pradhan
Cauchy
C
Sathyaprabha
Talakad N
TN
Raju
Trichur R
TR
Satishchandra
Parthasarathy
P
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001341:Autonomic Nervous System / Q000503:physiopathology*; D002874:Chromosome Mapping; D002884:Chromosomes, Human, Pair 15 / Q000235:genetics; D055028:Comparative Genomic Hybridization; D004562:Electrocardiography; D004827:Epilepsy / Q000235:genetics* / Q000503:physiopathology*; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D017384:Sequence Deletion; D016615:Telomere / Q000502:physiology