Effectiveness of high rate and delayed detection ICD programming by race: A MADIT-RIT substudy

Abstract

Introduction: Data on inappropriate and appropriate ICD therapy, and efficacy of ICD programing strategies by race are limited.

Methods: In MADIT-RIT, we evaluated the risk of ICD therapy by race, and the efficacy of high rate cut-off ventricular tachycardia (VT) zone ≥200 beats per minute (bpm) (Arm B), or 60 seconds delay in VT zone 170-199 bpm (Arm C), compared to 2.5 seconds delay at 170 bpm (Arm A) among black and white patients.

Results: MADIT-RIT enrolled 272 (20%) black and 1119 (80%) white patients. The risk of inappropriate therapy was similar among blacks and whites, HR 1.25, 95% CI (0.82-1.93), P = 0.30. High rate cut-off or delayed VT therapy was associated with significant reductions in inappropriate therapy among whites, Arm B versus Arm A, HR 0.15, 95% CI (0.08-0.29), P < 0.0001, Arm C versus Arm A, HR 0.19, 95% CI (0.11-0.33), P < 0.001, and black individuals Arm B versus Arm A, HR 0.24, 95% CI (0.01-0.56), P = 0.0001, Arm C versus Arm A, HR 0.30, 95% CI (0.13-0.68), P = 0.004, P interaction > 0.10). However, delayed VT therapy was associated with a trend toward greater reduction in appropriate therapy in black individuals, HR 0.08, 95% CI (0.03-0.27), P < 0.0001 relative to white individuals, HR 0.27, 95% CI (0.16-0.43), P < 0.0001, P interaction = 0.077.

Conclusion: In MADIT-RIT, high rate and delayed detection ICD programming provided similar benefit with reductions in both inappropriate therapy and unnecessary appropriate therapy among black and white individuals. CLINICALTRIALS.

Gov identifier: NCT00947310.

Keywords: ICD programming; MADIT-RIT; ethnicity; inappropriate ICD therapy; outcome; race.