Natriuretic peptides are strong and independent predictors of incident AF and subsequent outcomes.[5,29–31] Two smaller studies have suggested correlations between NT-proBNP and LA volume among AF patients undergoing CA.[31,32] Our study expands those findings to a broader AF population, and implicates that NT-proBNP may not only be a marker for heart failure, but also a useful surrogate for LA volume estimation in patients with AF. This evidence concerns the gene NPPB and heart failure.