Page 303 - Clinical Small Animal Internal Medicine

27 Feline Myocardial Disease 271

VetBooks.ir Cat with tachypnea/suspected acute CHF

O , (sedation?)
2
?Absent breath
sounds ventrally Auscultation

Gallop or Normal or murmur
Arrhythmia

Thoracocentesis Pleural effusion “In-house” Echo Echo not available

Obvious LA Normal or
enlargement equivocal LA

Fluid analysis, Congestive heart
cytology
failure likely Additional tests Consider
respiratory
disease
NT-proBNP
Thoracic
Furosemide high low radiography
1–2 mg/kg IV to effect Cardiomegaly &
pulmonary infiltrates Normal heart

If BP <100 mmHg,
no murmur
Pimobendan
1.25 mg q12 h PO

Figure 27.2 Initial approach to the cat with tachypnea and suspected heart disease. Diagnostic tests are shaded in blue, therapy is
shaded in pink. A combination of auscultation, rapid and focused “in‐house” ultrasound examination, and other diagnostic tests can
provide information on probability that the cat’s tachypnea is due to congestive heart failure (CHF) or noncardiac disease. BP, blood
pressure; Echo, echocardiography; LA, left atrium.

Other common causes of a heart murmur in cats evaluate the potential risk of cardiac complications
include physiologic (or nonpathologic) murmurs, as well such as CHF or ATE. Classifying cats as either “low
as anemia, hyperthyroidism, and hypertension. risk” or “high risk” facilitates management.

Is There an Underlying Systemic Cause Heart Disease Present; High Risk or Low Risk?
of Myocardial Disease?
One of the most useful prognostic indicators for cats
It is helpful to view feline myocardial disease in terms with cardiomyopathy is LA size. Cats with HCM and
of those with and without a specific systemic cause, as normal LA size can be considered to be at low risk of
treatment of any underlying cause is essential. It is CHF and ATE. Cats with LA enlargement fall into a
vital to identify hypertension, hyperthyroidism or higher risk category. If echocardiography is not available
anemia, as specific treatment requirements will differ to assess LA size, thoracic radiographs are reasonably
for each. Blood pressure should be measured in all specific but poorly sensitive to detect LA enlargement.
cats with suspected heart disease, and T4 concentra- ARVC is an exception, as LA size is an indicator of risk
tions measured in older cats. Hematocrit should be for left heart disease and ARVC predominantly affects
checked if there is any concern that anemia may be the right heart. Plasma biomarkers such as NT‐proBNP
responsible for a murmur. For those cats where no and troponin‐I can help provide an indication of the
cause is identified or can be treated, it is important to severity of heart disease.