Seizure: European Journal of Epilepsy
Volume 19, Issue 7 , Page 453, September 2010

Peri-ictal heart rates depend on seizure-type

  • Rainer Surges

      Affiliations

    • Corresponding Author InformationCorresponding author at: Department of Epileptology, University Bonn, Sigmund Freud Str. 25, 53127 Bonn, Germany. Tel.: +49 228 28714778; fax: +49 228 28719351.

Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London UK

Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London UK

Received 1 May 2010 published online 15 July 2010.

Article Outline

 

We have read with great interest the recent article of Nilsen and colleagues.1 The authors have investigated heart rates at different peri-ictal time points in non-generalized seizures of patients with partial epilepsy and compared those to peri-ictal heart rates in patients who had had secondarily generalized tonic–clonic seizures (SGTC). Their major finding was that patients with SGTC had higher pre-ictal heart rates.

In the context of cardiovascular regulation, it is of particular note that patients with refractory epilepsy undergo substantial alterations of the autonomic nervous system.2 Likewise, seizure-onset zone (e.g. frontal vs. temporal lobe), lateralization of seizure-onset (asymmetry of cortical representation of autonomic function), and gender are likely to influence peri-ictal heart rate.3, 4 Therefore, the authors correctly conclude that their “findings should be replicated in independent samples, preferably with paired design comparing complex partial seizures with SGTC in the same subjects”.

We have recently done just that and investigated peri-ictal heart rate in patients with refractory temporal lobe epilepsy who had both non-generalized and SGTC during video-EEG telemetry.5 This paired design controls for many of the major confounders detailed above. Our major findings were that SGTC lead to higher ictal heart rates and sustained postictal tachycardia, whereas pre-ictal heart rate was not dependent on seizure-type within the same patient. Unexpectedly, we also observed enhanced abnormal shortening of the QT interval, a risk factor for ventricular arrhythmia.6 Therefore, these cardiac alterations may be one plausible link between sudden unexpected death in epilepsy and occurrence of generalized tonic–clonic seizures.

Taken together, this suggests that the findings of Nilsen et al. are indicative of a difference between patients who have secondarily generalized seizures and those that do not (or have them less commonly). Since secondarily generalized seizures are a risk factor for SUDEP, this finding in itself may be of some importance.

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References 

  1. Nilsen KB, Haram M, Tangedal S, Sand T, Brodtkorb E. Is elevated pre-ictal heart rate associated with secondary generalization in partial epilepsy?. Seizure. 2010;19:291–295
  2. Ronkainen E, Ansakorpi H, Huikuri HV, Myllylä VV, Isojärvi JI, Korpelainen JT. Suppressed circadian heart rate dynamics in temporal lobe epilepsy. J Neurol Neurosurg Psychiatry. 2005;76:1382–1386
  3. Adjei P, Surges R, Scott CA, Kallis C, Shorvon S, Walker MC. Do subclinical electrographic seizure patterns affect heart rate and its variability?. Epilepsy Res. 2009;87:281–285
  4. Kirchner A, Pauli E, Hilz MJ, Neundörfer B, Stefan H. Sex differences and lateral asymmetry in heart rate modulation in patients with temporal lobe epilepsy. J Neurol Neurosurg Psychiatry. 2002;73:73–75
  5. Surges R, Scott CA, Walker MC. Enhanced QT shortening and persistent tachycardia after generalized seizures. Neurology. 2010;74:421–426
  6. Schimpf R, Borggrefe M, Wolpert C. Clinical and molecular genetics of the short QT syndrome. Curr Opin Cardiol. 2008;23:192–198

PII: S1059-1311(10)00140-8

doi:10.1016/j.seizure.2010.06.011

Seizure: European Journal of Epilepsy
Volume 19, Issue 7 , Page 453, September 2010

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