The Role of Vitamin D in the Pathophysiology of Chronic Failure

Patients will undergo at baseline and regular intervals: * clinically indicated bloodwork/urine and echocardiogram testing * biomarker studies Upon enrolment in the study patients will be divided into 4 groups normal, mildly deficient and severely deficient. Normal and mild vitamin D levels will receive no treatment while severe Vitamin D deficiency will be randomized (50/50) to receive no treatment or vitamin D treatment. They will be seen in the heart failure clinic every 6 months. The patients will be followed for 26 months.