title: Novel Techniques in Epilepsy Management: Venous Pacing and Capture of Electrical Activity in the Primate Cortex.
abstract: OBJECTIVE
  Pharmacotherapy for epilepsy is limited with 30% of patients refractory to this approach of suppressing seizures. Current surgical options are invasive and carry significant morbidities including infection, bleeding, and the potential for deleterious neurocognitive effects. As a result, there is a burgeoning need for innovation to develop safer and efficacious interventions.
  
  
  METHODS
  Four distinct catheters (2 existing: Cardima catheter, Standard EPT Blazer catheter; 2 new prototypes: balloon catheter, basket catheters) were tested in 12 baboons (21-30 kg, 100% male). For each, we assessed whether or not the catheter was able to be maneuvered safely in various locations of the cerebral venous system, provide adequate cortical tissue contact to record signals, detect these signals as normal or abnormal, successfully stimulate the cortex, and capture the cortical tissue. Locations trialed included the petrosal sinus, straight sinus, vein of Galen, and occipital vein. Pacing cycle length and pacing thresholds varied among experiments.
  
  
  RESULTS
  Successful mapping was conducted in all 12 baboons. The pacing cycle length varied from 75 ms to 650 ms depending on location of the cortex. Pacing threshold was recorded in 4/12 (33%) of the experiments; data is not available for the remaining 8/12 experiments. The threshold values ranged from 0.3 - 20 mAmps. Capture of cortical electrical activity was observed in 11/12 (91.7 %) experiments though the number of successful capture and stimulation attempts varied among experiments. The most reliable and consistent capture occurred with the use of our novel prototyped over-the-wire balloon catheter (9/12; 75%) and basket catheter (3/3; 100%). Necropsy and histology were performed post-experimentation, and only minimal complications were noted (Table 1).
  
  
  CONCLUSIONS
  New electrode design can be maneuvered safely in the venous system, provide adequate cortical tissue contact to record signals, detect these signals as normal or abnormal, successfully stimulate the cortex, and capture cortical tissue. These novel devices merit further study in chronic baboons to establish long-term efficacy of continuous seizure recording.
authors.affiliation: Mayo Medical School, Mayo Clinic, Rochester, MN.
authors.forename: Prakriti
authors.initials: P
authors.lastname: Gaba
authors.affiliation: Division of Cardiovascular Disease, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Christopher V
authors.initials: CV
authors.lastname: DeSimone
authors.affiliation: Instituto Brasília de Arritmia, Brasília, Brazil.
authors.forename: Benhur D
authors.initials: BD
authors.lastname: Henz
authors.affiliation: Division of Cardiovascular Disease, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
authors.affiliation: Division of Cardiovascular Disease, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Bruce
authors.affiliation: Division of Cardiovascular Disease, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: David R
authors.initials: DR
authors.lastname: Holmes
authors.affiliation: Division of Cardiovascular Disease, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Malini
authors.initials: M
authors.lastname: Madhavan
authors.affiliation: University of Texas, Austin.
authors.forename: Krithika
authors.initials: K
authors.lastname: Vasudevan
authors.affiliation: Biomerics, Rogers, MN.
authors.forename: Douglas
authors.initials: D
authors.lastname: Wahnschaffe
authors.affiliation: Biomerics, Rogers, MN.
authors.forename: Steven
authors.initials: S
authors.lastname: Berhow
authors.affiliation: Mayo Clinic Rochester, MN.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Danielsen
authors.affiliation: Mayo Clinic Rochester, MN.
authors.forename: Dorothy J
authors.initials: DJ
authors.lastname: Ladewig
authors.affiliation: Mayo Clinic Rochester, MN.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Mikell
authors.affiliation: Division of Cardiovascular Disease, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Johnson
authors.affiliation: Division of Cardiovascular Disease, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Scott H
authors.initials: SH
authors.lastname: Suddendorf
authors.affiliation: Division of Cardiovascular Disease, Department of Internal Medicine, Mayo Clinic, Rochester, MN; ICRC - Department of Cardiovascular Diseases, St Anne's University Hospital, Brno, CZ.
authors.forename: Tomas
authors.initials: T
authors.lastname: Kara
authors.affiliation: Division of Neurology, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Worrell
authors.affiliation: Division of Cardiovascular Disease, Department of Internal Medicine, Mayo Clinic, Rochester, MN; Department of Pediatrics and Adolescent Medicine Mayo Clinic, Rochester, MN.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Asirvatham
keywords: Epilepsy; cerebral cortex; primates; venous pacing