[1] Linkoping Univ, Dept Biomed Engn, Linkoping, Sweden
[2] Linkoping Univ, Dept Comp & Informat Sci, Linkoping, Sweden
[3] Univ Ljubljana, Fac Elect Engn, Ljubljana, Slovenia
[4] Univ Uppsala Hosp, Dept Cardiothorac Surg, Uppsala, Sweden
[5] Linkoping Univ Hosp, Linkoping Heart Ctr, S-58185 Linkoping, Sweden