[1] Univ Hosp Bern, Neurol, CH-3010 Bern, Switzerland
[2] Univ Hosp Munster, Neurol, Munster, Germany
[3] Brighton & Sussex Univ Hosp, Cardiol, Brighton, E Sussex, England
[4] Univ Calgary, Foothills Hosp, Hotchkiss Brain Inst, Neurol, Calgary, AB, Canada
[5] Univ Hosp Munster, Cardiol, Munster, Germany
[6] Imperial Coll Healthcare NHS Trust St Marys Hosp, Neurol, London, England
[7] Davisville Med Ctr, Neurol, Toronto, ON, Canada
[8] Kiel Migraine & Headache Ctr, Neurol, Kiel, Germany
[9] Kiel Migraine & Headache Ctr, Cardiol, Kiel, Germany
[10] Davisville Med Ctr, Cardiol, Toronto, ON, Canada
[11] Imperial Coll Healthcare NHS Trust St Marys Hosp, Cardiol, London, England
[12] Univ S Manchester Hosp, Cardiol, Manchester M20 8LR, Lancs, England
[13] Salford Royal Hosp, Cardiol, Salford, Lancs, England
[14] Univ Hosp Bern, Cardiol, CH-3010 Bern, Switzerland