Key result
AAIR cuts AF risk ~73% versus dual chamber pacing with a short AV delay.
Why the study?
Does rate adaptive single chamber atrial pacing (AAIR) reduce atrial fibrillation and thromboembolism compared to dual chamber pacing (DDDR) in patients with sick sinus syndrome and normal AV conduction?
RCT (n=177)
randomly assigned
Does rate adaptive single chamber atrial pacing (AAIR) reduce atrial fibrillation and thromboembolism compared to dual chamber pacing (DDDR) in patients with sick sinus syndrome and normal AV conduction?
Relative Risk: 0.27 (95% CI 0.09–0.83)
Absolute Event Rate: 7.4% vs 23.3%
p-value: p=0.02
In patients with sick sinus syndrome and normal AV conduction, single chamber atrial pacing (AAIR) significantly reduces the incidence of atrial fibrillation compared to dual chamber pacing (DDDR).
Supports AAIR over short-AV DDDR to lower AF in sick sinus syndrome with intact AV conduction; extends randomized pacing-mode comparisons.
OBJECTIVE: To analyse the occurrence of atrial fibrillation (AF) and thromboembolism in a randomised comparison of rate adaptive single chamber atrial pacing (AAIR) and dual chamber pacing (DDDR) in patients with sick sinus syndrome and normal atrioventricular (AV) conduction, in which left atrial dilatation and decreased left ventricular fractional shortening had been observed in the DDDR group. METHODS: 177 consecutive patients with sick sinus syndrome (mean (SD) age 74 (9) years, 104 women) were randomly assigned to treatment with one of three pacemakers: AAIR (n = 54), DDDR with a short rate adaptive AV delay (n = 60) (DDDR-s); or DDDR with a fixed long AV delay (n = 63) (DDDR-l). Analysis was intention to treat. RESULTS: Mean follow up was 2.9 (1.1) years. AF at one or more ambulatory visits was significantly less common in the AAIR group (4 (7.4%) v 14 (23.3%) in the DDDR-s group v 11 (17.5%) in the DDDR-l group; p = 0.03, log rank test). The risk of developing AF in the AAIR group compared with the DDDR-s group was significantly decreased after adjustment for brady-tachy syndrome in a Cox regression analysis (relative risk 0.27, 95% confidence interval (CI) 0.09 to 0.83, p = 0.02). The benefit of AAIR was highest among patients with brady-tachy syndrome. Brady-tachy syndrome and a thromboembolic event before pacemaker implantation were independent predictors of thromboembolism during follow up (relative risk 7.5, 95% CI 1.6 to 36.2, p = 0.01, and relative risk 4.7, 95% CI 1.2 to 17.9, p = 0.02, respectively). CONCLUSIONS: During a mean follow up of 2.9 years AAIR was associated with significantly less AF. The beneficial effect of AAIR was still significant after adjustment for brady-tachy syndrome. Brady-tachy syndrome was associated with an increased risk of thromboembolism.
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Lola Qvist Kristensen (2004) conducted an RCT in Sick sinus syndrome (n=177). Rate adaptive single chamber atrial pacing (AAIR) vs. Dual chamber pacing (DDDR) with short or long AV delay was evaluated on Atrial fibrillation (AF) at one or more ambulatory visits (RR 0.27, 95% CI 0.09-0.83, p=0.02). Single chamber atrial pacing (AAIR) significantly reduced the risk of atrial fibrillation compared to dual chamber pacing with a short AV delay (RR 0.27; 95% CI 0.09-0.83; P=0.02).