Table 1:

American College of Veterinary Internal Medicine’s classification scheme for myxomatous mitral valve disease in dogs

Disease stageDescription
Stage APatients with no current evidence of heart disease that are at high risk for future development of disease (eg, any cavalier King Charles spaniel without a cardiac murmur)
Stage BPatients with evidence of structural heart disease (a left apical systolic heart murmur) but no current or previous evidence of congestive heart failureStage B1Patients that have no radiographic or echocardiographic evidence of cardiac remodellingStage B2Patients with radiographic or echocardiographic evidence of left-sided heart enlargement
Stage CPatients with past or current evidence of congestive heart failure (even if clinically stable on therapy)
Stage DPatients with end-stage disease with clinical signs of congestive heart failure that are refractory to standard therapy (furosemide, pimobendan, an ACE inhibitor ± spironolactone). Advanced therapeutic strategies are necessary to achieve clinical stabilisation in these patients
  • Adapted from Atkins and others (2009)