Patent ID: 7181278

Claim:
A method for operating a cardiac rhythm management device, comprising: delivering paces to both ventricles with one ventricle designated as a rate chamber and the other ventricle as a synchronized chamber; sensing depolarizations from the rate chamber; delivering a rate chamber pace upon expiration of a ventricular escape interval that is reset by a rate chamber sense, the reciprocal of the ventricular escape interval being the lower rate limit; pacing the synchronized chamber in accordance with a synchronized pacing mode such that a synchronized chamber pace is delivered at a specified pacing instant defined with respect to expiration of the ventricular escape interval; measuring an R—R interval associated with each rate chamber sense, an R—R interval being the time between a rate chamber sense and a preceding rate chamber sense or pace, with the reciprocal of the R—R interval thus being the measured intrinsic ventricular rate; and, delivering ventricular rate regularization therapy by adjusting the ventricular escape interval in accordance with a measured R—R interval so that the lower rate limit is adjusted to move toward the measured intrinsic ventricular rate.