Resting Heart Rate Does Not Reflect the Degree of Beta-Blockade in Subjects with Heart Failure on Chronic Beta-Blocker Therapy

We investigated the relationship between resting heart rate (HR) and two measures of beta-1 receptor sensitivityblockade: (1) the percentage of maximal predicted heart rate reached during exercise (MPHR), and (2) the HR increase per unit of circulating norepinephrine (NE) or the chronotropic responsiveness index (CRI) in 28 patients with systolic CHF on chronic beta-blocker therapy. Our results show that resting HR is not associated with HR response during exercise nor with beta-1 receptor sensitivity to circulating NE.