[1] Skaraborg Hosp, Sleep Med Unit, Dept Neurol & Rehabil Med, SE-54185 Skovde, Sweden
[2] Univ Gothenburg, Sahlgrenska Acad, Gothenburg, Sweden
[3] Skaraborg Hosp, Dept Internal Med, SE-54185 Skovde, Sweden
[4] Skaraborg Hosp, Dept Cardiol, SE-54185 Skovde, Sweden
[5] Skaraborg Hosp, Dept Cardiol, Lidkoping, Sweden
[6] Skaraborg Hosp, Dept Internal Med, Lidkoping, Sweden
[7] Sahlgrens Univ Hosp, Dept Cardiol, Gothenburg, Sweden