Page 152 - Problem-Based Feline Medicine

144 PART 3 CAT WITH SIGNS OF HEART DISEASE

● Surgery should be accomplished as soon as the tion, the shunt fraction increases and if significant, vol-
patient is a good anesthetic risk. ume overload of the right and left heart is present.
● If heart failure is present, a period of stabilization
Mitral regurgitation may occur secondary to left heart
prior to surgery is required.
volume overload or congenital abnormalities of the for-
● See treatment for HCM (page 130) for therapy of
mation of the valve.
heart failure.
● Surgery is contraindicated in right to left shunts. Kittens with severe disease develop left-sided conges-
Treatment is mainly palliative. tive heart failure by 6 weeks of age.
● If clinical signs of lethargy, tachypnea and/or col-
lapse are present and if the packed cell volume Clinical signs
is above 60–65% periodic phlebotomy is indicated.
Signs depend on the degree of shunt fraction.
Phlebotomy decreases blood viscosity and improves
peripheral perfusion. The presence of clinical signs Most cats are asymptomatic.
alone is an indication for phlebotomy.
At the left heart base, a soft systolic ejection murmur is
● If there are signs of right-side heart failure, diuret-
heard. It is often also heard on the right side of the chest.
ics will be necessary.
● Rest is recommended. Signs of increased respiratory rate, dyspnea or col-
lapse may be seen while playing.
Stunted growth is seen in severe cases.
Prognosis
Some cases present with ascites, suggesting right-side
Left to right PDA.
heart failure.
● Prognosis is good for long-term survival after sur-
gical correction.
Diagnosis
● Even in animals presented in heart failure, success-
ful correction of the PDA results in resolution of Congenital murmur is found over the left heart base.
signs. A normal life expectancy is seen in most of The murmur is systolic and usually soft.
these cases.
Radiographic findings
● Right to left PDA.
– Prognosis is poor for long-term survival, how- Pulmonary over-circulation demonstrated by a promi-
ever many cats can still live for several years nent and enlarged vasculature of the lungs.
with minimal symptoms.
Areas of focal alveolar densities representing pul-
monary edema may be found.
ATRIAL SEPTAL DEFECT
Generalized cardiomegaly.

Classical signs Electrocardiographic findings
● Soft systolic murmur is heard over the left Sinus tachycardia (HR > 220 bpm) if heart failure is
heart base and may radiate to the apex. present
● Dyspnea. Evidence of left ventricular hypertrophy with a tall
● Collapse. R wave in lead II (> 0.9 mV)

In cases where the defect may interrupt or deviate the
Pathogenesis His bundle, notching and prolongation of the QRS may
be seen.
Left to right shunting occurs through the atrial septal
defect.
Echocardiographic findings
In the absence of significant mitral regurgitation, the Echocardiographic evidence of an atrial septal defect is
shunt fraction is small and animals may not have any seen as echo drop out at the regions of the interatrial
symptoms. With increased amounts of mitral regurgita- septum.