An exploration of the association between ischemic etiology and the likelihood of heart failure hospitalization following cardiac resynchronization therapy.

BACKGROUND: Myocardial scarring resulting from cardiomyopathy with ischemic etiology may interfere with effective lead placement during implantation of multi-lead cardioverter-defibrillators for cardiac resynchronization therapy (CRT-D). Extensive scarring is known to be associated with poorer physiological and survival outcomes in patients who undergo CRT-D. HYPOTHESIS: Ischemic CRT-D recipients respond as well as nonischemic recipients, using hospital admission for heart failure (HF) as a measure of response.
METHODS: Patients who underwent CRT-D between February 1, 2013, and February 1, 2014, were identified in an insurer's claims. Inclusion required 1 year of enrollment pre- and post-CRT-D. The sample was divided into nonischemic and ischemic groups, and a subset of the ischemic group with a history of ST-segment elevation myocardial infarction (STEMI) was identified. The likelihood of HF hospital admissions in the year before and after CRT-D was computed for each group, as well as for the subset of patients with HF admissions prior to CRT-D.
RESULTS: A significant (P = 0.02) association was found between ischemic etiology and the post-CRT-D HF admission likelihood. No association was found between history of STEMI vs nonischemic status and likelihood of post-CRT-D HF admission. All groups had significantly lower risk of HF admissions after CRT-D. None of the comparisons involving only patients with a HF hospitalization in the year prior to CRT-D were significant.
CONCLUSIONS: Patients with nonischemic etiology were significantly less likely to experience a HF admission after CRT-D, but the risk of HF admission improved significantly in all groups after CRT-D.