Sinus node dysfunction associated with AF progression but not worse outcomes

January 6, 2016 – Larry Jackson, MD, and his colleagues used data from ORBIT-AF to study the treatment patterns and outcomes of SND patients.

Sinus node dysfunction (SND) is associated with more comorbidities in atrial fibrillation (AF) patients, but not worse outcomes, according to a new study by DCRI researchers.

The study, led by the DCRI’s Larry Jackson, MD (pictured), appears in the online edition of the journal Clinical Cardiology.

larry-jackson-newsSND refers to a number of conditions in which the sinus node — the heart’s natural pacemaker — fails to work properly. Patients with SND are known to be at higher risk of atrial tachyarrhythmias, including AF. To date, however, the treatment patterns and outcomes of SND patients have not been well understood. Classifying AF patients by SND status is important because of the limitations on the type of medical therapies that can be used in patients with SND without a pacemaker and the likelihood of future pacemaker requirements.

In this study, Jackson and his colleagues used data from the Outcomes Registry for Better Informed Treatment–Atrial Fibrillation (ORBIT-AF) to describe the prevalence, clinical characteristics, treatment, and outcomes associated with SND. ORBIT-AF is a prospective, multicenter registry of patients with AF from across the United States. The researchers analyzed data from 9,631 patients enrolled in the registry between June 2010 and August 2011.

Of these patients, 1,710 (17.7 percent) had SND at the time of enrollment. Patients with SND were more likely to have hypertension, coronary artery disease, valvular heart disease, heart failure (HF) thyroid disease, prior cerebrovascular events, prior interventional therapy for AF, and lower left ventricular ejection fraction. Patients with SND had a higher risk for AF progression, but the researchers found no association between the condition and any other negative outcome.

Pharmacologic treatment for patients with AF and SND did not differ from that of patients with AF alone, a finding the researchers noted with concern because current AF guidelines consider pharmacological therapy in patients with AF and advanced sinus-node disease a class III recommendation, unless a cardiac pacemaker has been implanted. Of the 1,710 patients with SND, 519 (30 percent) were not treated with a pacing system, suggesting the need for evidence-based guidelines for SND patients with severe symptoms treated with pharmacological drug therapy without a pacemaker.

In addition to Jackson, the study’s DCRI authors included Sung Hee Kim, PhD; Jonathan P. Piccini, MD, MHS; Laine Thomas, PhD; and Eric Peterson, MD, MPH.