Cardiopulmonary Exercise Testing in Patients with Cardiac Pacemakers: From Device Optimization to Individualized Cardiac Rehabilitation.

Permanent cardiac pacing abolishes symptomatic bradycardia, yet a substantial proportion of recipients remain limited on exertion. Chronotropic incompetence is present in about half of pacemaker-wearing patients when assessed by the Wilkoff index, and the rate-responsive function intended to correct it is frequently left at the settings applied at implantation. Read across the whole cardiopulmonary exercise test rather than at peak effort, the relationship between heart rate and oxygen consumption distinguishes an inadequate sensor slope, an activity threshold set too high, a reaction time out of step with the onset of exercise, and an upper rate limit reached prematurely, each with a distinct correction. Reprogramming alters the result of the test within 24 h, so the settings should be corrected before rehabilitation begins. The objective is not the highest achievable rate but the individual ceiling above which the ventricle no longer converts frequency into output. Because heart rate is partly device-determined, training intensity should be anchored to the ventilatory threshold, to the corresponding workload and to perceived exertion, with heart rate being monitored for safety rather than used to set intensity. The aim of this review is to describe how cardiopulmonary exercise testing guides device reprogramming and training prescription in the pacemaker-wearing patient.