More than 400 000 persons in the United States are currently receiving maintenance dialysis as life-sustaining treatment for end-stage renal disease (ESRD), with more than 90% receiving in-center hemodialysis. Mortality rates in the ESRD population in the United States remain extremely high (18%-20% per year) despite a slight downward trend during the past 2 to 3 years. Most deaths among patients with ESRD are due to cardiovascular disease, with exceptionally high rates, particularly on an age-adjusted basis, of heart failure, stroke, and sudden death. In fact, sudden death accounts for roughly 1 in 4 deaths among patients receiving dialysis.1