Red blood cell distribution width and atrial fibrillation in patients with sick sinus syndrome

Sick sinus syndrome (SSS) is associated with atrial fibrillation (AF). Red blood cell distribution width (RDW) is a marker of anisocytosis of erythrocytes and is related to inflammatory stress. Recently, RDW has been associated with AF. The aim of the present study was to evaluate the potential association of RDW with AF history in patients with SSS.

Consecutive patients with symptomatic SSS undergoing dual-chamber pacemaker implantation were screened. Baseline clinical, laboratory, echocardiographic, and electrocardiographic parameters were recorded. Conventional inflammatory indexes were also assessed. Multivariate logistic regression analysis and receiver operating characteristic (ROC) curve analysis for parameters associated with AF were performed.

The final study population consisted of 101 patients (47 men); median age: 77 [73-82] years. The demographic and clinical characteristics were comparable between tachy-brady (AF history) patients (n=32) and patients with other forms of SSS (n=69). Left atrial diameter was increased in tachy-brady patients [44 (39-48)mm vs. 39 (36-44)mm; p=0.05]. Also, the RDW was greater in these patients [14.7 (13.6-15.4)% vs. 13.7 (13.4-14.3)%; p=0.02]. Multivariate analysis showed that RDW is independently associated with AF (OR: 1.58; 95% CI: 1.06-2.85; p=0.04). The ROC curve analysis showed that the area under the curve was 0.69 (p=0.028). A RDW cut-off point of 14 was related to AF with a sensitivity of 70% and a specificity of 69%.

RDW is associated with AF history in patients with SSS. The prognostic value of RDW in terms of future AF development and arrhythmia perpetuation in these patients should be further examined.