Page 100 - Feline Cardiology

98 Section C: Congenital Heart Disease

sented for exertional dyspnea (Schrope and Kelch
2007). Syncope and exercise intolerance could also be
expected.

Physical Examination
The heart murmur of pulmonic stenosis should be a
Congenital Heart Disease and Martin 2003; Schrope and Kelch 2007). Tricuspid
systolic murmur ausculted loudest at the left base over
the pulmonic valve but it may radiate widely (Johnson

regurgitation associated with right ventricular hypertro-
phy and pressure overload may result in a systolic
murmur ausculted over the right hemithorax.

Differential Diagnosis
A double chambered right ventricle may produce similar
Figure 10.7. Doppler echocardiograph from a cat with a patent clinical findings. An echocardiogram with Doppler
ductus arteriosus (PDA). Continuous flow is noted to be shunting should differentiate the two defects.
into the pulmonary artery from the ductus.
Diagnostic Testing
Electrocardiography
A normal sinus rhythm and normal axis may be
Prognosis
observed, or a right axis shift consistent with right ven-
The prognosis for patent ductus arteriosus, particularly tricular hypertrophy may be present. Right atrial enlarge-
if diagnosed early, is very good. Once cats develop pul- ment (tall P wave) may be noted.
monary hypertension and reversal of shunting, the
prognosis becomes guarded to poor. Radiography
Radiographs may appear to be normal in many cases.
PULMONIC STENOSIS, PULMONARY Alternatively, evidence of right atrial or ventricular
ARTERY STENOSIS
enlargement may be noted. A bulge due to poststenotic
Pulmonic stenosis is a narrowing or a stenosis that can dilation may be observed within the pulmonary artery.
occur at the subvalvular, valvular, or supravalvular level
(Keirstead et al. 2002; Johnson and Martin 2003). Echocardiography
Additionally, pulmonary artery stenosis, a stenosis of the Two-dimensional echocardiography may demonstrate
main or branched pulmonary artery, has also been some degree of right ventricular and/or papillary muscle
recently reported in several cats (Schrope and Kelch 2007). hypertrophy, flattening of the interventricular septum,
A breed predisposition has not been noted. These right atrial enlargement, and/or dilation of the pulmo-
defects have been reported in 1 Devon Rex, several nary artery above the stenosis. Doppler echocardio-
domestic shorthairs, and 1 Persian (Johnson and Martin graphic studies should demonstrate an increased velocity
2003; Schrope and Kelch 2007). across the stenotic area. The severity of the stenosis is
typically based on Doppler velocity across the narrowing
Pathophysiology and the calculated pressure gradient.
Pulmonic stenosis or stenosis of the pulmonary artery,
(main pulmonary artery or a peripheral pulmonary Treatment
artery) results in similar hemodynamic effects. Increased Interventional therapy for pulmonic stenosis might be
right ventricular systolic pressure resulting in right ven- considered on a case-to-case basis. Balloon valvuloplasty
tricular concentric hypertrophy, septal flattening, right has been successfully performed in a cat with pulmonic
atrial dilation, and the development of right heart failure stenosis (Johnson and Martin 2003). Surgical palliation,
can all be observed. including placement of a patch graft, might also be con-
sidered in some cases. Medical therapy with atenolol
History and Chief Complaint
(6.25–12.5 mg orally q 12 hours), a beta blocker, may
Clinical signs appear to be rare, with many animals also be considered if the patient is not a candidate for
remaining asymptomatic for many years. One cat pre- valvuloplasty and is not in congestive heart failure.