The latest cardiac pacing mode to become available is the dual-chamber, rate-modulated mode (referred to as DDDR), which restores both rate responsiveness and atrioventricular synchrony in patients with sinus node dysfunction and atrioventricular block. This pacing mode combines dual-chamber and single-chamber rate-modulated technologies. Thus, it is necessary to program both a maximum tracking rate and a maximum sensor rate, as in dual-chamber and single-chamber rate-modulated devices, respectively. These two upper rate limits are usually programmed to equivalent values. The case described herein illustrates one advantage of programming discrepant upper rate limits. The rapid tracking of supraventricular tachycardias was prevented by lowering the maximum tracking rate to 100 ppm. A maximum sensor rate of 140 ppm still allowed an adequate rate response during activity.