The clinical signs of feline heartworm infection can be acute or chronic. Pulmonary or central nervous system signs are seen more often in acute cases. Chronic signs may include episodic pulmonary disorders, gastrointestinal disorders, lethargy, or right-sided congestive heart failure. Nonspecific symptoms may include coughing, dyspnea, vomiting, anorexia, lethargy, and weight loss.
Some cats may exhibit no signs at all other than vomiting. Acute pulmonary thromboembolism resulting in severe dyspnea, weakness, vocalization of distress, and sudden death are not uncommon manifestations of heartworm disease in cats. Physical exam findings that could indicate heartworm disease include respiratory abnormalities, vomiting, heart murmur or gallop heart rhythms, syncope, and bloodwork suggestive of parasitic infection.
