An open-label, blinded-endpoint, randomized, prospective trial investigating the effects of vitamin D administration on plasma renin activity in patients with stable chronic heart failure.

INTERVENTION: Trade Name: Calci‐chew Product Name: Calciumcarbonate Pharmaceutical Form: Chewable tablet Trade Name: Etalpha Product Name: Alfacalcidol Pharmaceutical Form: Capsule, soft CONDITION: Heart Failure ; MedDRA version: 12.0 Level: LLT Classification code 10008908 Term: Chronic heart failure PRIMARY OUTCOME: Main Objective: The main objective is to investigate the safety and efficacy of vitamin D administration in patients with stable CHF. Primary end point(s): The primary endpoint of this study is the plasma renin activity after 6 weeks of treatment with vitamin D compared to the PRA after 6 weeks without treatment. Secondary Objective: Secondary objectives are to evaluate the effect of vitamin D administration on echocardiographic parameters of left ventricular (LV) function and N‐Terminal‐pro‐Brain Natriuretic peptide (NT‐proBNP.); Monitoring of safety endpoints including vital signs, physical examination, and laboratory analyses, biochemical indices of kidney function and bone homeostatis.; (Serious) adverse event monitoring. INCLUSION CRITERIA: The study population will consist of patients with chronic heart failure (NYHA Class II), = 18 years of age with LVEF = 45 %. Inclusion criteria • Out patients = 18 years of age, male or female. • Patients with a diagnosis of chronic heart failure (NYHA Class II) • LVEF = 45% at visit 1 (local measurement, measured within the past 6 months assessed by echocardiogram, MUGA or ventricular angiography) • Patients must be treated with an ACE‐i at a stable dose (at least enalapril 10 mg daily or any other ACE‐i, e.g. ramipril, quinapril, lisinopril, fosinopril, perindopril, trandolapril; on equivalent doses, or maximum tolerated dose) or if intolerant to ACE‐i with ARB therapy (Candesartan 8 mg daily or any other ARB in equivalent dose, or maximum tolerated dose) for at least 4 weeks prior to visit 1. • Patients must be treated with a beta blocker unless contraindicated or not tolerated at a stable dose for at least 4 weeks prior to visit 1 (