Cardiorespiratory phase determination has numerous applications during cardiac imaging. We propose a novel view-angle independent prospective cardiorespiratory motion gating technique for X-ray fluoroscopy images that are used to guide cardiac electrophysiology procedures. The method is based on learning coronary sinus catheter motion using principal component analysis and then applying the derived motion model to unseen images taken at arbitrary projections. We validated our technique on 7 sequential biplane sequences in normal and very low dose scenarios and on 5 rotational sequences in normal dose. For the normal dose images we established average systole, end-inspiration and end-expiration gating success rates of 100 %, 97.4 % and 95.2 %, respectively. For very low dose applications, the method was tested on images with added noise. Average gating success rates were 93.4 %, 90 % and 93.4 % even at the low SNR value of
, representing a dose reduction of more than 10 times. This technique can extract clinically useful motion information whilst minimising exposure to ionising radiation.