Background: Limited heart rate (HR) rise (HRR) during exercise, known as chronotropic incompetence (CI), is commonly observed in the context of chronic heart failure (CHF). HRR is closely related to workload, the limitation of which is characteristic of CHF. Whether CI is a causal factor for exercise intolerance, or simply an associated feature remains unknown. Objectives: The aim of this investigation was to clarify the role of the HR on exercise capacity in CHF. Methods: This series of investigations consisted of a retrospective cohort study and two interventional randomised cross-over studies to assess: 1) the relationship between HRR and exercise capacity in CHF and the effect of 2) increasing HR, and 3) lowering HR on exercise capacity in CHF assessed using symptom limited treadmill exercise testing with metabolic gas exchange to measure peak oxygen consumption (pVO2) in patients with CHF due to left ventricular (LV) systolic dysfunction. Results: The three key findings of this project are: 1) although exercise capacity is related to HRR in CHF, the association is much weaker in severe CHF as compared to those with normal LV function, 2) increasing HRR using rate-adaptive pacing (versus fixed-rate pacing) in unselected patients with CHF does not improve peak exercise capacity and 3) acutely lowering baseline and peak HR by adjusting pacemaker variables in conjunction with a single dose of ivabradine (versus placebo) does not adversely affect exercise capacity in unselected CHF patients. Conclusions: Our data refute the contention that CI contributes to impaired exercise capacity in CHF. This finding has widespread implications for pacemaker programming and the use of heart-rate lowering agents. (The Influence of Heart Rate Limitation on Exercise Tolerance in Pacemaker Patients [TREPPE]; NCT02247245) (J Am Coll Cardiol 2016;67:1885–96)
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)