MONITORING HEART PERIOD VARIABILITY CHANGES DURING SEIZURES .1. METHODS

The analysis of heart period variability (HPV) is a sensitive tool for detecting alterations in cardiac activity, which has been used to quantify changes in autonomic influences on cardiac function. We have developed a technique that utilizes time-and frequency-domain analysis of HPV to detect and quantify seizure-related alterations of cardiac autonomic regulation. Electrocardiographic (EKG) data obtained from video/EEG or ambulatory EEG recordings are processed off-line to provide graphic and tabular data regarding seizure-related changes in HPV. Using the preictal period as a baseline, ictal and postictal periods are analyzed to determine statistically significant changes in HPV during the ictal and postictal periods. This technique can detect seizure-related alterations of cardiac activity that are not apparent on routine inspection of the EKG. Some of these changes are evident prior to any apparent behavioral or EEG changes indicative of seizure activity. HPV analysis appears to be an important adjunct to video/EEG monitoring. It can allow detection and quantification of the cardiac effects of seizures that are likely to be mediated by changes in cardiac autonomic inputs. The method has promise in revealing important information regarding the mechanisms by which seizures may influence cardiac activity. In addition, HPV monitoring may provide an earlier and more reliable indication of the time of seizure onset than is apparent from inspection of video or EEG data alone. © 1990.