NPPB and congestive heart failure: • Elevated values in cats with heart disease, CHF, and left atrial dilation • ANP >77.5 pg/ml (sensitivity 66.3%; specificity 84.6%) – distinguishing cats with cardiomyopathy from healthy individuals • Left atrial dilation – ANP >110.9 pg/ml (sensitivity 73.6%; specificity 93.5%) • Association between NT-proBNP, atrial size, and left ventricular free wall thickness • NT-proANP is not valid for differentiating healthy and cardiomyopathy cats