Ventricular activation in atrial fibrillation (AF) is irregular. Our aim was to develop and validate a new model of atrioventricular conduction (AVC) in AF. Intracardiac electrograms (IEGM) were recorded in 4 dogs in AF near the AV junction. Four timing intervals with 8 parameters were used to create a model of AVC: absolute and relative refractory periods, slow and normal conduction times. 26406 RR intervals were used to calculate and 2142 intervals to validate the prediction accuracy. Using the optimal combination of the parameters the RR interval prediction had an average error of 99±80 ms, validation showed a value of 99±77 ms. In conclusion, prediction of RR intervals in AF is possible using IEGM near the AV junction.