Systems and methods for pacing cardiac conductive tissue are described. An exemplary system includes an electrostimulation circuit that may generate HBP pulses to stimulate patient physiologic conduction pathway, such as a His bundle or a bundle branch. The system includes an arrhythmia detector to detect an atrial tachyarrhythmia (AT) with intermittent ventricular conduction. A control circuit may sense ventricular activation and, in response to the detected AT indication, determine or update a His-bundle pacing (HBP) configuration. The HBP may be recursively updated on a beat-by-beat basis using the sensed ventricular activation. The electrostimulation circuit may deliver HBP according to the determined or adjusted HBP configuration to regularize ventricular rate during AT.
