Atrial flutter and sick sinus syndrome

Abstract

Background: Sick sinus syndrome (SSS) is a common condition resulting in reduced quality of life, syncope, and permanent pacemaker (PPM) implantation, but predictors have not been elucidated. Whereas atrial arrhythmias are frequently associated with SSS, we hypothesized that atrial flutter (AFL) would strongly predict SSS, given shared relationships with right atrial and particularly crista terminalis fibrosis.

Objective: The study aimed to assess the impact of AFL on the occurrence of SSS and associated syncope and PPM implantation.

Methods: Health care databases were used to identify adults aged ≥18 years receiving hospital-based care in California in 2005-2019. International Classification of Diseases codes were used to identify diagnoses and procedures. Patients were classified on the basis of the presence of AFL and atrial fibrillation (AF). Cox proportional hazards models adjusting for demographics and comorbidities were employed.

Results: We included 29,357,609 individuals (54% female; mean age, 46 years), 101,243 with AFL alone, 1,674,680 with AF alone, and 284,547 with AF and AFL. After adjustment for age, sex, race and ethnicity, and comorbidities, AF, AFL, and both arrhythmias were each associated with increased risk of SSS and associated syncope and PPM implantation (all P < .001). In the population with AF, an additional AFL diagnosis conferred a higher risk for development of SSS (hazard ratio [HR],1.62; 95% confidence interval, 1.59-1.64), syncope (HR, 1.63; 1.54-1.72), and PPM implantation (HR, 1.74; 1.70-1.79).

Conclusion: AFL is associated with an increased risk of incident SSS and its adverse consequences, especially in patients with coexisting AF. AFL may be useful for risk stratification strategies to predict, to prevent, and to treat SSS.

Keywords: Atrial fibrillation; Atrial flutter; Pacemaker; Sick sinus syndrome; Syncope.