C-reactive protein, left atrial volume, and atrial fibrillation: a prospective study in high-risk elderly.

BACKGROUND: The data regarding the interrelationships of high-sensitive C-reactive protein (CRP), left atrial (LA) volume, and atrial fibrillation (AF) are sparse. Additionally, while LA volume has been shown to be useful for prediction of AF in low-to-moderate risk populations, its predictive value in clinically high-risk populations is unknown. METHODS: SAFHIRE (Study of Atrial Fibrillation in High Risk Elderly) is an ongoing prospective study of the pathophysiology of first AF in persons aged > or = 65 years with > or = 2 other AF risk factors [systemic hypertension, proven coronary artery disease, heart failure (HF), diabetes]. Participants are followed annually, and undergo an interview, physical examination, blood work, electrocardiogram, and echocardiogram assessment. RESULTS: Of 800 participants, mean age of 74 +/- 6 years, 34 developed first AF over 1.7+/- 0.9 years. A history of systemic hypertension and proven coronary artery disease was present in 97% and 78%, respectively. CRP was unrelated to LA volume on univariable or multivariable analyses (P > 0.10), and not predictive of first AF on univariable or multivariable models (all P > 0.10). Indexed LA volume was an independent predictor of first AF (unadjusted P< 0.0001; age and sex adjusted P = 0.0006; adjusted for multiple factors, HR 1.3/5 ml per m(2), 95% CI, 1.09 to 1.48, P = 0.001). CONCLUSION: In this elderly population at high clinical risk for the development of first AF, CRP was unrelated to LA volume and nonpredictive of first AF, while indexed LA volume was incremental to clinical risk factors for the prediction of first AF.