Incident Atrial Fibrillation in Systemic Sclerosis: The Predictive Role of B-Type Natriuretic Peptide

Abstract

Introduction: Atrial fibrillation (AF) is common in patients with systemic sclerosis (SSc) and is associated with significant morbidity, mortality, and healthcare expenditures. The aim of this study was to prospectively determine the incidence and the independent predictors of AF in this patient population. Methods: Forty-nine patients (age 50.15 +/- 9.25 years, 87.8% female) and 21 healthy controls, all in sinus rhythm, were studied. Evaluation included blood sampling, B-type natriuretic peptide (BNP) measurement, comprehensive electrocardiography and echocardiography at baseline, and 24h ambulatory Holter monitoring at baseline and every 6 months. Results: During a mean follow-up of 72 +/- 24 months, 18 SSc patients (36.7%) developed AF (SSc-AF group) while 31 remained in sinus rhythm (SSc-SR group); all subjects in the control group (Cl group) remained in SR. Baseline differences between SSc-AF, SSc-SR, and Cl groups included: a) left ventricular (LV) mass: 84.5 +/- 26 vs. 71.8 +/- 18.6 vs. 60.5 +/- 32.6 g/m(2), respectively (p=0.017); b) mitral tissue Doppler imaging E velocity: 14.5 +/- 2.8 vs. 17.5 +/- 3.4 vs. 20.5 +/- 4.4 cm/s (p<0.001); c) left atrial (LA) volume: 18.8 +/- 7.8 vs. 13.5 +/- 5.1 vs. 9.7 +/- 5.4 cm(3)/m(2) (p<0.001); d) LA active emptying volume: 7.6 +/- 2.7 vs. 4.7 +/- 3.2 vs. 3.3 +/- 2.2 cm(3)/m(2) (p<0.001); and e) logBNP: 1.78 +/- 0.47 vs. 1.31 +/- 0.54 vs. 0.66 +/- 0.38 pg/mL (p<0.001). In Cox proportional hazard analysis, BNP was the only independent predictor of incident AF. Conclusion: Incident AF was high in SSc, especially in the presence of LV diastolic dysfunction with LA mechanical overload and elevated BNP levels. BNP was the only independent predictor of incident AF; therefore, it should be considered for risk stratification in this population.