Reduction in Inappropriate Therapy and Mortality Through ICD Programming
Does avoidance of inappropriate implantable cardioverter-defibrillator (ICD) therapies improve survival?
In the MADIT-RIT trial, 1,500 patients (mean age 63 years) who received an ICD for primary prevention of sudden cardiac death (SCD) were randomly assigned to either: 1) conventional programming: a detection zone of 170-199 bpm with a 2.5-second delay and atrial discriminators turned on, and a second zone at ≥200 bpm with a 1-second delay before delivery of the ICD therapy (n = 514); 2) high-rate group: therapy zone of ≥200 bpm, with a 2.5-second monitoring delay (n = 500); or 3) delayed-therapy group: a zone of 170-199 bpm with rhythm detection on and a 60-second therapy delay, a zone at ≥200 bpm with rhythm detection on and a 12-second therapy delay, and a third zone at ≥250 bpm with a 2.5-second therapy delay (n = 486). The patients were seen in a device clinic every 3-6 months. The primary endpoint was the first inappropriate ICD therapy.
A first inappropriate ICD therapy was significantly less prevalent in the high-rate (4%) and delayed-therapy (6%) groups than in the conventional group (21%). Compared to the conventional group, mortality at 2.5 years was significantly lower in the high-rate group (hazard ratio [HR], 0.45), and tended to be lower in the delayed-therapy group (HR, 0.56). Appropriate ICD therapies also were significantly less prevalent in the high-rate (13%) and delayed-therapy (8%) groups than in the conventional group (27%).
Programming strategies that minimize inappropriate ICD therapies are associated with improved survival in patients receiving an ICD for primary prevention of SCD.
Because of the impact on patient survival, the results of this important study should be incorporated into clinical practice as soon as possible.
Keywords: Defibrillators, Implantable, Primary Prevention
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