Presentation

a) Signalment:

• Middle aged cats, at times young adults may present
• Males may be more frequently affected than females
• Persians, Maine Coons and Ragdolls may be predisposed

b) History:

• Sudden development of dyspnea
• Anorexia
• Lethargy/weakness
• Syncope
• Limb paralysis if thromboembolic disease occurs
• Sudden death may occur (and may be the first sign of disease)
• Free of clinical signs; discovered in cats free of clinical signs when a heart murmur or gallop detected on physical examination was pursued

c) Physical Examination:

• Signs of congestive heart failure as outlined in of Clinical Evaluation of Heart Disease section
• Abdominal effusion is rare; pleural effusion is common
• Dysrhythmias, pulse deficits
• If thromboembolic disease occurs
  • Paralysis of the affected limb – usually a hindlimb
  • The muscle is hard, painful and cool
  • There is a weak or absent arterial pulse in the limb
  • A shortly clipped toe nail in the affected limb may fail to bleed
  • May be the first and only presenting sign of underlying cardiomyopathy of any type
• Gallop cardiac rhythms are frequent
• A systolic heart murmur of mitral insufficiency and/or left ventricular outflow obstruction may be present
• Note that the absence of a murmur or a gallop does not rule out the presence of HCM. In a recent study, 22% of cats with HCM had neither a murmur nor a gallop on physical examination.