[1] Norwegian Univ Sci & Technol, Fac Med, Dept Circulat & Med Imaging, Trondheim, Norway
[2] Trondheim Reg & Univ Hosp, St Olavs Hosp, Dept Cardiothorac Surg, Trondheim, Norway
[3] VID Specialized Univ, Haraldsplass, Bergen, Norway
[4] Oslo Univ Hosp, Rikshosp, Dept Resp Med, Oslo, Norway
[5] Univ Oslo, Fac Med, Dept Nursing Sci, Oslo, Norway
[6] Oslo Univ Hosp, Dept Res & Dev, Div Emergencies & Crit Care, Oslo, Norway
[7] Trondheim Reg & Univ Hosp, St Olavs Hosp, Dept Cardiol, Trondheim, Norway
[8] St Olavs Hosp, Natl Competence Ctr Complex Symptom Disorders, Trondheim, Norway