Heart Rate Reduction Is Associated With Reverse Left Ventricular Remodeling and Mechanism-Specific Molecular Phenotypes in Dilated Cardiomyopathy.

Background: Heart rate (HR) affects heart failure outcomes, via uncertain mechanisms that may include left ventricular remodeling. However, in human ventricular myocardium, HR change has not been associated with a particular remodeling molecular phenotype.

Methods: Patients with nonischemic dilated cardiomyopathy (N=22) in sinus rhythm and refractory to β-blockade for both HR lowering and reverse remodeling were randomized 2:1 double-blind to the HCN4 (hyperpolarization-activated cyclic nucleotide-gated potassium channel 4) channel inhibitor ivabradine or placebo for 24 weeks treatment while maintaining target doses of β-blockers.