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

backgroundMyocardial 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.

methodsPatients 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.

resultsA 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.

conclusionsPatients 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.