ALTERATION OF CARDIAC-FUNCTION IN PATIENTS WITH TEMPORAL-LOBE EPILEPSY - DIFFERENT ROLES OF EEG-ECG MONITORING AND SPECTRAL-ANALYSIS OF RR VARIABILITY

Purpose: Because several reports have described the relation between e pilepsy and cardiac arrhythmias and suggest that changes in autonomic neural control of the heart could be involved in the pathogenesis of s udden unexplained death in patients with epilepsy, the aim of this stu dy was to evaluate cardiac function in patients with temporal lobe epi lepsy. Methods: Sixty-five patients with epilepsy were evaluated by si multaneous ambulatory 24-h EEG-ECG monitoring, and in 30 of these, pow er spectral analysis of relative-risk (RR) variability also was carrie d out, both in the supine position and in a passive tilt position at 6 00. The power spectrum of RR variability, the two major spectral compo nents detectable at low frequency (LF) and at high frequency (HF), res pectively, and the LF/HF ratio were calculated. Results: By EEG-ECG mo nitoring, we recorded six partial seizures, and in four cases, dischar ges were associated with sinus tachycardia. However, interictally the occurrence of ventricular and supraventricular arrhythmias was not dif ferent from that in normal subjects. The spectral analysis of RR varia bility, on the other hand demonstrated in patients with epilepsy a sig nificant decrease in the total RR variability and in both of its compo nents (LF and HF) in the supine position, and of the LF/HF ratio in or thostatic position. Conclusions: These findings suggest that the spect ral analysis of RR variability may detect disorders of autonomic cardi ac control in patients with epilepsy, even in the absence of abnormal findings during ECG monitoring. This alteration, which is more severe in cases with right EEG focus, could play a role in the pathogenesis o f cardiac arrhythmias.