Thirteen days of rapid LV pacing produced the hemodynamic and neurohumoral hallmarks of established HF, with marked decreases in cardiac output (CO) and mean blood pressure (MBP), and rises in atrial pressure and plasma atrial and B-type natriuertic peptides (ANP and BNP, resepectively) (all p < 0.001 vs. Cont). This evidence concerns the gene NPPB and hydrops fetalis.