Clinical Studies and Outcomes
Danish II
A randomized comparison of atrial and dual-chamber pacing in 177 consecutive patients with sick sinus syndrome: echocardiographic and clinical outcome.
Nielsen JC, Kristensen L, Andersen HR, Mortensen PT, Pedersen OL, Pedersen AK.
JACC. 2003;42(4):614-623
Design: 177 consecutive patients with sick sinus syndrome (SSS) randomized to pacing treatment in AAIR or DDDR with a short AV delay (DDDR-S) or DDDR with a fixed long AV delay (DDDR-I).
Objectives: Compare AAI and DDD pacing in patients with SSS, as measured by echocardiography.
Key Results: Mean Follow-up – 2.9 ± 1.1 years:
- In both DDDR groups, LA diameter increased significantly (P < 0.05)
- In the DDDR-S group, LV fractional shortening decreased significantly (p < 0.01)
- Atrial fibrillation (AF) was significantly less common in the AAIR group (7.4% vs. 17.5% in DDDR-I group and 23.3% in DDDR-S group, p = 0.03, log rank test)
- In the AAIR group, no significant changes were observed in LA or LV diameters
MOde Selection Trial (MOST)
Adverse effect of ventricular pacing on heart failure and atrial fibrillation among patients with normal baseline QRS duration in a clinical trial of pacemaker therapy for sinus node dysfunction
Sweeney MO, Hellkamp AS, Ellenbogen KA, et al, for the MOde Selection Trial (MOST) Investigators.
Circulation. 2003;107:2932-2937.
1,339 patients from the MOde Selection Trial (MOST), a 6-year, prospective, randomized study, received either dual-chamber pacing (DDDR) or single-chamber ventricular pacing (VVIR) in sinus node dysfunction (SND). Ventricular desynchronization, imposed by ventricular pacing even when AV synchrony was preserved, increased the risk of heart failure hospitalization and atrial fibrillation in SND with normal baseline QRSd.
Canadian Trial of Physiologic Pacing
Progression to chronic atrial fibrillation after pacing: The Canadian Trial of Physiologic Pacing
Skanes AC, Krahn AD, Yee R, et al, for the CTOPP Investigators.
J Am Coll Cardiol. 2001;38:167-172.
2,568 patients from the Canadian Trial Of Physiologic Pacing (CTOPP), a multicenter, prospective, randomized study, were implanted with a ventricular-based or a physiologic pacing system. Physiologic pacing reduced the annual rate of development of chronic AF in these patients undergoing first pacemaker implants. Age ≥ 74 years, SA node disease, and prior AF predicted the development of chronic AF. Patients with structurally normal hearts appeared to derive greatest benefits.
DAVID Trial
Dual-chamber pacing or ventricular backup pacing in patients with an implantable defibrillator. The dual chamber and VVI implantable defibrillator (DAVID) trial
Wilkoff BL, Cook JR, Epstein AE, et al, for the DAVID Trial Investigators.
JAMA. 2002;288:3115-3123.
506 patients with indications for ICD therapy were enrolled in this multicenter, randomized clinical trial. All patients had an ICD with dual-chamber, rate-responsive pacing capability implanted, which was randomly programmed to ventricular backup pacing (VVI) or dual-chamber rate-responsive pacing (DDDR). For patients with standard indications for ICD therapy, no indication for cardiac pacing, and LVEF of ≤ 40%, dual-chamber pacing offered no clinical advantage over ventricular backup pacing and may be detrimental by increasing the combined end-point of death or hospitalization for heart failure.
