Thoracic radiographs are indicated for cats suspected of having heart disease but have low sensitivity for detecting hypertrophic heart disease.To help guide the diagnosis, testing for N-terminal pro B-type natriuretic peptide (NT-pro BNP), a peptide rapidly produced by myocardial cells after stretch or hypoxia, can be used.The vagally mediated bradycardia can be offset with anticholinergic drugs (e.g., atropine or glycopyrrolate); however, these drugs will increase heart rate, myocardial work, and oxygen consumption, none of which are desirable in cats with hypertrophic heart disease.Therefore, anticholinergics should be considered only if the opioid produces severe bradycardia (i.e., heart rate Although sedative effects in cats are also minimal when pure mu opioid agonists are administered, the cats often become euphoric, as demonstrated by rubbing, purring, rolling, and kneading with the front paws.Those cats with symptomatic heart disease often exhibit reduced body conditioning, abnormal lung sounds, and pale or cyanotic mucus membranes, coupled with a history of tachypnea or dyspnea, lethargy, and/or inappetence.Cats with cardiomyopathies present unique sedation and anesthesia challenges, depending on the type of myocardial disease.The incidence of heart murmurs in apparently healthy cats is only 16% to 44%.
Development of safe sedative or anesthetic protocols requires an understanding of the type and severity of a patient’s cardiac disease.
The majority of cardiac diseases in cats are acquired and progressive; the minority are congenital.
To minimize this risk, keep in mind that there are no safe sedative or anesthetic drugs; there are only safe practices in their delivery.
Although numerous cardiomyopathies occur in cats, the most common is hypertrophic (obstructive) cardiomyopathy.
This disease is characterized by diffuse or segmental hypertrophy of the left ventricular myocardium with development of cardiomyofiber disarray.