Author + information
- Received October 2, 2002
- Revision received January 6, 2003
- Accepted January 30, 2003
- Published online August 20, 2003.
- Jens C Nielsen, MD, PhD*,
- Lene Kristensen, MD*,
- Henning R Andersen, MD, DMSc*,* (, )
- Peter T Mortensen, MD*,
- Ole L Pedersen, MD, DMSc† and
- Anders K Pedersen, MD, DMSc*
- ↵*Reprint requests and correspondence:
Dr. Henning R. Andersen, Department of Cardiology, Skejby Hospital, University of Aarhus, Brendstrupgaardsvej, 8200 Aarhus N, Denmark.
Objectives A randomized trial was done to compare single-chamber atrial (AAI) and dual-chamber (DDD) pacing in patients with sick sinus syndrome (SSS). Primary end points were changes in left atrial (LA) size and left ventricular (LV) size and function as measured by M-mode echocardiography.
Background In patients with SSS and normal atrioventricular conduction, it is still not clear whether the optimal pacing mode is AAI or DDD pacing.
Methods A total of 177 consecutive patients (mean age 74 ± 9 years, 73 men) were randomized to treatment with one of three rate-adaptive (R) pacemakers: AAIR (n = 54), DDDR with a short atrioventricular delay (n = 60) (DDDR-s), or DDDR with a fixed long atrioventricular delay (n = 63) (DDDR-l). Before pacemaker implantation and at each follow-up, M-mode echocardiography was done to measure LA and LV diameters. Left ventricular fractional shortening (LVFS) was calculated. Analysis was on an intention-to-treat basis.
Results Mean follow-up was 2.9 ± 1.1 years. In the AAIR group, no significant changes were observed in LA or LV diameters or LVFS from baseline to last follow-up. In both DDDR groups, LA diameter increased significantly (p < 0.05), and in the DDDR-s group, LVFS decreased significantly (p < 0.01). Atrial fibrillation was significantly less common in the AAIR group, 7.4% versus 23.3% in the DDDR-s group versus 17.5% in the DDDR-l group (p = 0.03, log-rank test). Mortality, thromboembolism, and congestive heart failure did not differ between groups.
Conclusions During a mean follow-up of 2.9 ± 1.1 years, DDDR pacing causes increased LA diameter, and DDDR pacing with a short atrioventricular delay also causes decreased LVFS. No changes occur in LA or LV diameters or LVFS during AAIR pacing. Atrial fibrillation is significantly less common during AAIR pacing.
- Received October 2, 2002.
- Revision received January 6, 2003.
- Accepted January 30, 2003.
- American College of Cardiology Foundation