Detect Supraventricular Tachycardia Study - Detect Supraventricular Tachycardia Study
The goal of the trial was to evaluate the effect of dual-chamber detection compared with single-chamber detection on inappropriate shocks caused by misdetection of supraventricular tachycardia (SVT) among patients with implantable cardioverter defibrillators (ICDs).
Patients Enrolled: 400
Mean Follow Up: 6 months
Mean Patient Age: Mean age 65 years
Mean Ejection Fraction: Baseline mean ejection fraction 32%
Clinical indication for ICD therapy and received a dual-chamber defibrillator
Age <18 years, Mobitz II or greater heart block, previous atrioventricular node ablation, permanent atrial fibrillation or flutter, pre-existing separate pacemaker pulse generator that was not to be explanted, life expectancy of <1 year, or on a transplant waiting list, intra-aortic balloon pump, inotropic drug (not digitalis) necessary for hemodynamic support, chronic serious bacterial infection, inability to receive nonthoracotomy ICD, or inability to program device as per protocol
Proportion of SVT episodes inappropriately detected from the time of programming until crossover or end of study
Time to first inappropriately treated episode, VT/ventricular fibrillation sensitivity, number of arrhythmia-related hospitalizations or clinic visits, and early termination rate
All patients received a dual-chamber ICD and were randomized within 3 days of implantation to single-chamber (n = 199) or dual-chamber (n = 201) detection. Patients but not physicians were blinded to randomization. Programming was done to minimize ventricular pacing.
The main reason for ICD implantation was for primary prevention of sudden death (67%). Twenty-five percent of patients had a known history of SVT, and 81% had coronary artery disease. SVTs occurred in 31% of the single-chamber group and 37% of the dual-chamber group, with 42% of the episodes in the single-chamber group and 69% of the episodes in the dual-chamber group due to SVT (p = 0.06). The crossover rate from single-chamber to dual-chamber detection was higher than crossover in the other direction (n = 17 vs. n = 2, p < 0.001).
The primary endpoint of inappropriate detection of SVT was 39.5% in the single-chamber group compared with 30.9% in the dual-chamber group (p = 0.03). The median number of episodes among patients with an SVT episode was 4 (range 1-58). The median number of episodes until the first inappropriate detection was 1.5 in the single-chamber group and 4 in the dual-chamber group, but there was no difference in the time to first inappropriate detection (103 days vs. 108 days, p = 0.45). Inappropriate therapy (antitachycardia pacing/shock) due to inappropriate detection occurred more frequently in the single-chamber group (33.0% vs. 24.8%, p = 0.02), but there was no difference in the overall rate of inappropriate shock (p = 0.18).
Mortality occurred in 3.5% of patients in each group. There was no difference in the frequency of complications, with 1 patient with atrial lead fracture/failure, 4 with atrial lead dislodgment, and 4 with atrial sensing errors.
Among patients with ICDs for a range of indications, use of dual-chamber detection was associated with a lower rate of inappropriate SVT detection through 6 months of follow-up compared with single-chamber detection.
Delivery of inappropriate shocks was a result of misclassification of SVT as VT causes undue pain and can be anxiety-provoking, impairing patients' quality of life. Several prior studies have not shown a difference in inappropriate therapies between single- and dual-chamber detection. The present study demonstrated a reduction in inappropriate detection and inappropriate therapies, but did not show a difference in inappropriate shock, due in part to a higher rate of pacing in the single-chamber group.
Friedman PA, McClelland RL, Bamlet WR, et al. Dual-chamber versus single-chamber detection enhancements for implantable defibrillator rhythm diagnosis: the detect supraventricular tachycardia study. Circulation 2006;113:2871-9.
Keywords: Coronary Artery Disease, Tachycardia, Supraventricular, Follow-Up Studies, Quality of Life, Pain, Death, Sudden, Cardiac, Defibrillators, Implantable
< Back to Listings