Page 570 - Problem-Based Feline Medicine

562 PART 8 CAT WITH ABNORMAL LABORATORY DATA

arteriosus, atrial or ventricular septal defects), but Medical therapy is instituted to treat the physiological
appropriate secondary polycythemia may also occur effects of cardiac failure. This may include treatment for
with left-sided or biventricular congestive heart fail- hypertension, cardiac rate disturbances, arrhythmia, pul-
ure, as occurs with cardiomyopathy. monary edema and/or pleural effusion. See The Cat With
Abnormal Heart Sounds and/or an Enlarged Heart and
The Cat With Tachycardia, Bradycardia, or an Irregular
Clinical signs
Rhythm on pages 124, 157 for treatment details.
Feline cardiac disease usually presents at an
Hypoxia in tetralogy of Fallot is decreased when the
advanced stage, with dyspnea and hypoxia (oxygen
condition is treated by aortic banding, which reduces
saturation <92%).
right-to-left blood flow.
There may be open-mouth breathing and cyanosis.
Hematocrit should be reduced to 45% before sur-
Mucosae are dark pink, or purple if the poly- gery is performed to treat any underlying condi-
cythemia is caused by hypoxia from right to left shunt- tions, to decrease the risk of thromboembolism during
ing of blood in the heart or lungs. surgery. This is achieved by performing phlebotomy
and administering intravenous fluids.
Tachycardia and arrhythmia may be detected on car-
diac auscultation, with accompanying crackles and
wheezes on thoracic auscultation from pleural effusion Prognosis
and/or pulmonary edema.
The prognosis for feline cardiac disease is guarded and
Congenital cardiac disease often causes stunted may be poor if the disease is initially diagnosed at an
growth in comparison with littermates. advanced stage.

Diagnosis CHRONIC PULMONARY DISEASE*

Initial diagnosis may be made on auscultatory abnor-
Classical signs
malities, together with other signs of cardiac failure
such as dyspnea and hypertension. ● ± History of chronic coughing.
● Dyspnea may be acute, chronic or
Thoracic radiology reveals cardiomegaly with or
intermittent.
without pulmonary edema and/or pleural effusion.
● Cyanosis and open-mouth breathing in
Cardiac chamber abnormalities, abnormal wall thick- severe cases.
nesses and/or pressure or flow irregularities may be ● Crackles, wheezes and sometimes muffled
detected using echocardiology. cardiac sounds.
ECG abnormalities may be detected, although this is
See main references The Cat With Stridor (page 32),
not as common in cats as in dogs.
The Dyspneic or Tachypneic Cat (page 47), The Cat
With Hydrothorax (page 71) and The Coughing Cat
Differential diagnosis (page 90) for details.

Other causes of chronic hypoxia, such as pulmonary
disease, should be differentiated from hypoxia from Pathogenesis
congenital or degenerative cardiac disease.
Respiratory disease causes chronic hypoxia, stimu-
lating increased secretion of erythropoietin and
Treatment resulting in polycythemia.
Treatment of cardiac conditions is dependent on cor- The most common cause of chronic pulmonary disease
rect diagnosis of the cause of cardiac failure. in cats is feline asthma/feline bronchitis complex,