Open Journal of Clinical Diagnostics, 2012, 2, 18-22 OJCD doi:10.4236/ojcd.2012.22004 Published Online June 2012 (http://www.SciRP.org/journal/ojcd/ ) Biomarkers and atrial fibrillation: A new paradigm for assessing the progression of left atrial endocardial remodelling Philippe Chevalier 1 , Alina Scridon 2 1 Hospices Civils de Lyon, Hôpital Louis Pradel, Service de Rythmologie, Lyon, France 2 University of Medicine and Pharmacy of Targu Mures, Targu Mures, Romania Email: philippe.chevalier@chu-lyon.fr , alinascridon@yahoo.com Received 29 December 2011; revised 13 February 2012; accepted 25 February 2012 ABSTRACT Atrial fibrillation is a heterogeneous disorder that is usually characterized by paroxysmal onset, particu- larly in patients without structural heart disease. De- fining biological markers of atrial remodelling would help identify patients at high risk who would benefit most from prophylactic treatment and careful moni- toring. Biomarkers of atrial fibrillation progression would be helpful for following patients that present with asymptomatic atrial fibrillation. Notably, the roles of such markers in the pathophysiology of atrial fibrillation must be determined. Some markers may indicate the presence, complications or progression of the disease, while others may be involved in key pathological processes and thus represent novel therapeutic targets. Although a number of markers have been reported as potential predictors of parox- ysmal atrial fibrillation progression towards persis- tent arrhythmia, their usefulness and clinical value need further validation. This report reviews several newly identified markers of atrial fibrillation pro- gression. Keywords: Atrial Fibrillation; Biomarkers; Progression 1. INTRODUCTION Atrial fibrillation is a heterogeneous disorder that varies in terms of clinical presentation, natural history, and re- sponse to therapy [1-3]. This cardiac arrhythmia is usu- ally characterized by paroxysmal onset, particularly in patients without structural heart disease, but the natural history of the arrhythmia is to worsen [4]. Experiments in goats have shown that “atrial fibrillation begets atrial fibrillation” and that over the long term, atrial fibrillation progresses in frequency and duration to become persis- tent and finally permanent [5,6]. However, it remains unclear whether paroxysmal, per- sistent and permanent atrial fibrillation represent three different stages of the same pathophysiological process or whether they represent three distinct disorders. Mark- ers that predict the clinical progression of atrial fibrilla- tion and its complications are yet to be defined. 2. PREDICTORS OF ATRIAL FIBRILLATION PROGRESSION A number of clinical variables, such as valvular disease, alcohol consumption, age, left atrial dimension, and the occurrence of stroke or heart failure, have been proposed as predictors of atrial fibrillation progression [7]. In a retrospective study, Jahangir et al. identified older age at diagnosis and the presence of QRS abnormalities on ECG (prolonged QRS duration of 110 to 120 ms, notching or slurring of the QRS complex, or low anterior forces with small R waves in the precordial leads) as predictors of progression towards permanent atrial fibrillation. However, age was the sole independent predictor of pro- gression in multivariable analysis [8]. Several other parameters were also identified as pre- dictors of the transition from paroxysmal to persistent atrial fibrillation, including duration of the arrhythmia [9], left ventricular dysfunction [10], enlarged left atria, prolonged filtered P-wave duration, and a low root mean square voltage for the last 30 ms of the filtered P wave [11]. The CARAF study showed that a more rapid heart rate during atrial fibrillation at baseline is associated with a lower risk of developing permanent atrial fibrillation [12]. 3. BIOMARKERS OF ATRIAL FIBRILLATION PROGRESSION Biomarkers are defined as measurable components, such as cells, proteins and/or metabolic products that reflect, either directly or indirectly, one or more biological proc- esses involved in a disease state [13]. Such markers help Published Online June 2012 in SciRes. http://www.scirp.org/journal/ojcd