Rate-Modulated pacing

The concept of rate-modulated (rate-responsive, rate-adaptive) pacemakers is to move beyond simple backup pacing for bradycardias to helping a patient adapt to physiologic stress with an increase in heart rate, even if the patient's intrinsic sinus node normally would not allow this to occur. The development of dual-chamber pacemakers allows a patient to increase the heart rate if he or she is in sinus rhythm and sinus function is intact. Many patients, however, have sick sinus syndrome that prevents normal physiologic sinus node response to exercise, stress, or chronic atrial fibrillation.......