Heart rate and EKG changes in 102 seizures: analysis of influencing factors

Sudden unexpected death in epilepsy (SUDEP) is a major cause of mortality in patients with epilepsy. Since cardiac arrhythmia may be a responsible factor, we sought to determine the prevalence of significant EKG abnormalities during and immediately after epileptic seizures, and to identify risk factors for these changes.

We retrospectively assessed changes in heart rate (HR) and the occurrence of EKG abnormalities in 102 seizures (71 non-generalized, 31 generalized) from 41 patients using video-EKG-EEG recordings.

The majority of seizures (101/102; 99%) led to an increase in HR. EKG abnormalities (other than sinus tachycardia) were noted in 22/102 (21.5%) seizures overall. Most EKG changes were benign, but potentially serious changes occurred in 6/102 (6%) seizures and 4/41 (10%) patients. These included ST-depression (5 seizures in 3 patients) and T-wave inversion (1 seizure). Ictal HR was higher (P<0.03) and EKG-abnormalities were more common (P<0.05) in generalized compared to non-generalized seizures. Ictal EKG abnormalities were seen in 35% of generalized seizures, including potentially serious changes in 13%. There was a trend towards higher risk of ictal EKG abnormalities when seizures arose from sleep or from the left hemisphere, when MRI showed evidence of hippocampal sclerosis, and when ictal HR was higher. Age and seizure duration had no effect on the occurrence of EKG abnormalities.

We conclude that ictal EKG abnormalities other than sinus tachycardia are not unusual, especially in generalized seizures. These findings may be relevant to the phenomenon of SUDEP.