A randomized comparison of atrial and dual-chamber pacing in 177 consecutive patients with sick sinus syndrome: echocardiographic and clinical outcome

• Published in: Journal of the American College of Cardiology 2003-08, Vol.42 (4), p.614-623
• Main Authors: Nielsen, Jens C, Kristensen, Lene, Andersen, Henning R, Mortensen, Peter T, Pedersen, Ole L, Pedersen, Anders K
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Body Weights and Measures; Cardiac Pacing, Artificial - methods; Echocardiography; Female; Heart Atria - diagnostic imaging; Heart Atria - physiopathology; Heart Ventricles - diagnostic imaging; Heart Ventricles - physiopathology; Humans; Male; Middle Aged; Sick Sinus Syndrome - diagnostic imaging; Sick Sinus Syndrome - therapy
• ISSN: 0735-1097
• DOI: 10.1016/S0735-1097(03)00757-5

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. In patients with SSS and normal atrioventricular conduction, it is still not clear whether the optimal pacing mode is AAI or DDD pacing. 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. 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. 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.