HEART PERIOD VARIABILITY IN SEIZURE-RELATED SINUS ARREST

Analysis of heart period variability (HPV) is a valuable tool for the evaluation of autonomic influences over the cardiac cycle in patients at risk of sudden death. Using both time and frequency domain techniqu es, we analyzed the variation in heart period for five episodes from a 5-month-old infant who had recurrent periods of asystole related to g eneralized tonic-clonic seizures (GTCS). The frequency domain analysis consistently showed increased power in the low- (0.0-0.04 Hz), middle - (0.04-0.12 Hz), and high- (0.2-0.4 Hz) frequency bands during the ic tus as compared with preictal states, suggesting an increase in both p arasympathetic and sympathetic influences on the heart period during t hese seizures. Similar power spectra changes in other patients with GT CS are associated with tachycardia These findings are in contrast to H PV patterns detected in patients with cardiac disease at risk of sudde n death. This case suggests that sinus arrest produced by seizures may be related to more complex autonomic influences on heart period than are postulated with cardiogenic sudden unexpected death. (C) 1997 by E lsevier Science Inc.