The Effects of Active VItamin D on Left Atrial Volume Index

This is a pilot feasibility study to determine the effects of an activated vitamin D compound (paricalcitol) on heart structure (size) and function (ability to relax) in patients with normal kidney function and a form of heart failure known as HFPEF (heart failure and preserved ejection fraction). This study will also examine heart failure-related hospitalizations and changes in cardiac-stretch and biological markers that are believed to change along with heart size. Patients in this pilot study will be treated for a period of 48 weeks with paricalcitol at a dose previously approved by FDA (1 mcg per day) and followed-up for 4 weeks after treatment is completed.

Heart failure (HF) is among the top ten causes of hospitalizations in the US. It is estimated that \~40-50% of patients with HF have preserved ejection fraction (EF). Patients with heart failure and preserved ejection fraction (HFPEF) have normal systolic function, but impaired cardiac relaxation. The main causes of HFPEF include left-ventricular hypertrophy (LVH) and hypertension, hypertrophic cardiomyopathy, aortic stenosis with a normal EF, coronary artery disease and restrictive cardiomyopathies. Only a few small clinical trials have tested therapeutic interventions in patients with HFPEF, producing either small or negative effects. Relatively few drugs have effects on cardiac relaxation and are not candidates for chronic use, as they may have significant side effect profiles and/or are inconvenient to administer. Paricalcitol, an FDA-approved activated form of vitamin D, has been shown to slow LVH progression and improve parameters associated with diastolic function in animal models (see refs). Treatment with paricalcitol has also been associated with decreased cardiovascular morbidity and mortality in a historical cohort study of patients with end-stage renal disease (see refs). This is a single-center, single-arm, pilot study in 20 patients with HFPEF and normal renal function on stable medical therapy to evaluate the effects of paricalcitol on cardiac structure and function.