Heart failure severity, inappropriate icd therapy, and novel icd programming: A MADIT-RIT sub-study

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Conference Proceeding

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Heart Rhythm


Background: The effect of heart failure (HF) severity on inappropriate ICD therapy has not been thoroughly investigated. Objective: To determine the relationship between HF severity and inappropriate ICD therapy and the effect of novel ICD programming on this relationship. Methods: MADIT-RIT randomized patients to three ICDprogramming arms: conventional (Arm A), high-rate cut-off (Arm B: ≥200 beats per minute), and delayed therapy (Arm C: 60-second delay). We evaluated the impact of New York Heart Association (NYHA) Class III (n=256) versus Class I-II (n=251) on inappropriate ICD therapy in Arm A patients (n=514). We also assessed the benefit of novel ICDprogramming in Arms B and C relative to Arm A patients. Results: In Arm A patients, the overall risk of inappropriatetherapy was significantly higher in those with NYHA III versus NYHA I-II (HR=2.72, 95% CI: 1.71-4,34, p<0.001). This was consistent for inappropriate ATP (NYHA III vs. I-II: HR=2.73, 95% CI: 1.71-4.36, p<0.001), but not inappropriateshock (NYHA III vs. I-II: HR=1.37, 95% CI: 0.54-3.43, p=0.509). Patients with NYHA III in the conventional therapy arm were significantly more likely to experience inappropriatetherapy fo heart rate (HR)<200 bpm (NYHA III vs. I-II: HR=2.96, 95% CI: 1.82-4.81, p<0.001) but not for HR≥200 bpm (NYHA III vs. I-II: HR=1.07, 95% CI: 0.34-3.31, p=0.913). Novel ICD programming significantly reduced the risk of inappropriate ICD therapy in patients with NYHA III (Arm B vs. A: HR=0.09, p<0.001; Arm C vs. A: HR=0.19, p<0.001), and in those with NYHA I-II (Arm B vs. A: HR=0.23, p<0.001; Arm C vs. A: HR=0.27, p<0.001). Conclusion: Patients with more advanced HF have a greater risk of inappropriate ICDtherapy, particularly ATP related to supraventricular arrhythmias with heart rates < 200 bpm. Nevertheless, novel ICD programming with either a high-rate cut-off or delayed detection reduces the risk of inappropriate ICDtherapy in patients with both mild and advanced heartfailure.





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