Effectiveness of Cardiac Resynchronization Therapy with Defibrillator in At‐Risk Black and White Cardiac Patients

Background There are limited data regarding racial differences in response to cardiac resynchronization therapy with defibrillator (CRT‐D). Methods We assessed the effectiveness of CRT‐D, as compared to implantable cardioverter defibrillator (ICD) therapy alone, in reducing the risk of heart failure (HF) or death and changes in cardiac volumes among 1638 (90%) white patients and 143 (8%) black patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy (MADIT‐CRT). Results Enrolled black patients displayed a higher frequency of diabetes mellitus, treated hypertension, higher creatinine levels, and a lower distance walked in the baseline 6‐minute walk test. Kaplan‐Meier survival analysis showed that at 3 years of follow‐up the cumulative probability of HF or death was higher among blacks (29%) as compared with whites (22%; P = 0.05). Both black and white patients experienced similar and pronounced reductions in cardiac volumes with CRT‐D therapy (all P values for comparison between the two groups >0.10). Risk reduction conferred by CRT‐D therapy as not significantly different between blacks and whites (hazard ratio = 0.78 and 0.60, respectively; P for the difference = 0.44). However, possibly due to sample size limitations the CRT‐D versus ICD only adjusted risk for HF/death in blacks was not statistically significant. Conclusions Black patients in MADIT‐CRT experienced increased risk of HF or death as compared with whites, but displayed a similar magnitude echocardiographic response to CRT‐D. These findings suggest that cardiac resynchronization therapy may be an effective therapeutic modality in black patients. However, further studies are needed to assess the clinical response to CRT‐D in this high‐risk population.