Medicare began covering CRT-CD in 2005. HF registries (IMPROVE HF, Medicare NCDR-ICD) subsequently began to track long-term outcomes. Data from the IMPROVE-HF registry indicate that wide variation remains across different practices in the proportion of CRT devices implanted that also incorporate ICD functions (CRT-D) (Mehra, Yancy, et al., 2009). While HF is the fastest-growing cardiac diagnosis, patients are, on average, ten years older and otherwise sicker than those in COMPANION or similar studies, and the benefit of CRT-D therapy for these older patients is unclear. The registries and experts also suggest that there is both significant overuse and underuse of CRT-D therapy between regions—not all HF patients who are candidates for CRT-D therapy are offered it, and other HF patients may be receiving CRT-D therapy inappropriately. Some of the reasons are clear: About 80 percent of HF patients are treated by noncardiologists, who tend not to refer eligible patients to an interventional cardiologist for CRT therapy (Friedewald, Boehmer, et al., 2007). Interventional cardiologists, by contrast, may overutilize CRT and ICD: Many patients who received CRT were either not on OPT first or did not meet other current eligibility guidelines. In addition, more procedures are now being performed at low-volume centers by less-experienced practitioners, and this may be associated with higher complication rates.