1. A method for tracking a virtual electrode (VE) on a coronary sinus (CS) catheter in a fluoroscopic image sequence comprising: receiving user inputs indicating locations of a plurality of CS catheter electrodes and a location of a VE in a first frame of the fluoroscopic image sequence; detecting a VE part of the CS catheter in the first frame, wherein the VE part is a segment of the CS catheter between a most proximal electrode and the VE; initializing a catheter electrode template and a VE part template in a first frame of a fluoroscopic image sequence based on the input locations of the plurality of CS catheter electrodes and the input location of the VE in the first frame; and tracking the VE in a second frame of the fluoroscopic image sequence by: detecting electrode position candidates and catheter body point candidates in the second frame of the fluoroscopic image sequence using respective trained detectors; tracking the catheter electrode template in the second frame based on the detected electrode position candidates; generating VE part hypotheses based on the most proximal electrode in the catheter electrode template in the second frame; calculating a probability score for each of the VE part hypotheses; selecting one of the VE part hypotheses as the VE part result in the second frame based on the probability scores; and displaying the VE part result in the second frame.