Detect Supraventricular Tachycardia Study - Detect Supraventricular Tachycardia Study

Jul 12, 2006
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Date Published:
01/01/2006
Date Updated:
07/12/2006
Original Posted Date:
07/12/2006
References

Description:

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).

Study Design

Study Design:

Patients Enrolled: 400
Mean Follow Up: 6 months
Mean Patient Age: Mean age 65 years
Female: 20
Mean Ejection Fraction: Baseline mean ejection fraction 32%

Patient Populations:

Clinical indication for ICD therapy and received a dual-chamber defibrillator

Exclusions:

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

Primary Endpoints:

Proportion of SVT episodes inappropriately detected from the time of programming until crossover or end of study

Secondary Endpoints:

Time to first inappropriately treated episode, VT/ventricular fibrillation sensitivity, number of arrhythmia-related hospitalizations or clinic visits, and early termination rate

Drug/Procedures Used:

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.

Principal Findings:

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.

Interpretation:

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.

References:

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


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