question: What is the effect of ivabradine in heart failure with preserved ejection fraction?
answer: I(f)-channel inhibition potentially exhibits beneficial effects in diastolic heart failure.  In patients with heart failure with preserved ejection fraction (HFpEF), short-term treatment with ivabradine increased exercise capacity, with a contribution from improved left ventricular filling pressure response to exercise as reflected by the ratio of peak early diastolic mitral flow velocity to peak early diastolic mitral annular velocity.  Ivabradine has demonstrated benefits in HFpEF without improving mortality.	In db/db, a model of HFpEF, ivabradine improved vascular stiffness, left ventricular contractility, and diastolic function. Furthermore, ivabradine reduces cardiac fibrosis in hypercholesterolemic rabbits.