Abstract 1984: The DATAS Trial: Clinically Significant Adverse Events in Single vs Dual Chamber ICD
Background: Dual chamber (DC) ICD can potentially overcome some of the clinically relevant limitations of single chamber (SC) ICD. However, in the DAVID trial outcome was worse in DC-ICD patients. DATAS aimed to compare DC-ICD to SC-ICD in patients with class I SC-ICD indication, in the setting of strict programming recommendations to avoid pacing, and tiered therapies for atrial tachyarrhythmias (AT).
Purpose: To test if DC-ICD reduce clinically significant adverse events as compared to SC-ICD
Methods: Patients were randomly assigned to DC-ICD, SC-ICD or a DC-ICD device but programmed as SC-ICD (SC-simulated) and followed-up for at least 17 months. Patients in DC-ICD and SC-simulated crossed-over after 8 months (+ 1 month wash-out). Primary endpoint: clinically significant adverse events (CSAE), a composite of:
hospitalization (> 24 hr) or prolongation of hospitalization due to cardiovascular cause,
inappropriate shocks (≥ 2 episodes), and
sustained symptomatic AT that require urgent termination or last more than 48 hr leading to therapeutic intervention.
A pre-specified score (CSAE score) was developed to correct for clinical severity (e. g. consider death as the worst outcome). Sample size estimation was 300 analyzable patients. Estimated rate ratio accounted for duration of follow-up.
Results: from 354 randomized patients, 334 were analyzed. Baseline parameters: mean age: 64 ± 10 years, 84% male, 68% in NYHA class ≥ II, coronary disease 86%, mean LVEF 0.36 ± 0.13, AT 19%. The clinical risk of CSAE evaluated by the CSAE score was significantly lower in the DC-ICD group (RR 0.31; 95% CI 0.14 to 0.67; p = 0.003). The rate of CSAE score in the DC-ICD was 33% lower than in the SC-ICD. On each individual CSAE DC-ICD was similar or better than SC-ICD.
Conclusion: DC-ICD reduce clinically significant adverse events as compared to SC-ICD in patients without an indication for DC antibradycardia pacing.