Race and Risk of Ventricular Tachyarrhythmia or Death
What is the risk of ventricular tachyarrhythmia (VTA) or death in black and white patients implanted with implantable cardioverter-defibrillators (ICDs) or defibrillator and combined cardiac resynchronization therapy (CRT-D)?
This was a post hoc analysis of MADIT-CRT (Multicenter Automatic Defibrillator Implantation with Cardiac Resynchronization Therapy) trial, which enrolled mildly symptomatic heart failure (HF) patients. The risk for first VTA or death was evaluated in black (n = 139) versus white (n = 1,638) patients enrolled in the MADIT-CRT trial.
At 4 years of follow-up, the cumulative probability for a first VTA or death was higher among black (42%) as compared with white (34%) patients (p = 0.01). Multivariate analysis confirmed higher risk of VTA or death (hazard ratio, 1.60; p = 0.002) and higher risk of VTA alone (hazard ratio, 1.71; p = 0.002) in blacks compared with whites. The findings were similar in both ICD and CRT-D implanted patients. Independent risk factors for VTA among blacks included increased systolic blood pressure values and larger cardiac volumes.
The authors concluded that black patients have a significantly higher rate of VTAs or death compared to whites, with either an implanted ICD or CRT-D.
Prior studies showed that blacks have a higher rate of HF, higher mortality from HF, and higher risk of sudden cardiac death. However, they also suggested that the efficacy of defibrillators was no different by racial group. In the present study, black patients had 60% increased risk of VTA. There are multiple possible explanations for this: higher rates of hypertensive cardiomyopathy and left ventricular hypertrophy, among others. Because considerable differences do exist, all efforts should be made to increase the representation of black patients (and women) in medical and device trials of HF. The present study suggests that there are no significant race-to-treatment interactions in regard to echocardiographic response to CRT, a finding that should be confirmed in future studies.
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