Page 144 - Problem-Based Feline Medicine

136 PART 3 CAT WITH SIGNS OF HEART DISEASE

pulses, cool extremities and cyanosis of the nail bed. In ity (E wave > 1.1 m/s) and normal or decreased atrial
some cases a history of episodic lameness is given. flow component.
Thrombi (homogeneous mass) in the left atrium and/or
Diagnosis
ventricle may be found.
Usually a history of heart murmur, arrhythmia, col-
Differential diagnoses
lapse or respiratory distress is present. Some cats
may not have an audible murmur but a gallop rhythm is Congenital heart disease.
commonly heard. ● A murmur is usually present from birth. Most con-
genital murmurs do not change in loudness with
Diagnosis is based on supportive radiographic, electro-
alterations of the heart rate. Congenital murmurs
cardiographic and especially echocardiographic findings.
are usually relatively loud.
Radiographic findings
Dilated cardiomyopathy.
Severe left atrial or biatrial enlargement. ● Murmurs are usually very soft, and in many cases may
not be present. A gallop rhythm is usually present.
Enlarged pulmonary veins can be seen.
Hypertrophic cardiomyopathy.
Pulmonary edema with or without pleural effusion
● It is difficult to differentiate on auscultation from
may be present.
restrictive or intermediate/unclassified cardiomy-
Electrocardiographic findings opathy. A gallop rhythm may be more common in
Ventricular arrhythmias are more common than with restrictive or intermediate/unclassified cardiomy-
other types of feline myocardial disease. opathies.
Atrial fibrillation is more common than with HCM; Intrathoracic masses.
and if present is usually associated with extreme ● A murmur may not be present unless there is com-
dilatation of the left and/or right atria. pression of the heart by the mass or concurrent
unrelated heart disease. Most commonly, dyspnea
Tachycardia (heart rate above 220), ventricular conduc-
and lethargy are seen.
tion disturbances (notched QRS), tall R waves on lead
II (>0.9 mV) may be seen. Feline asthma or chronic bronchitis.
● Unless cardiac disease is also present, most cats do
Echocardiographic findings not have a murmur. Cough and increased respira-
Severe left atrial or biatrial enlargement is com- tory rate are common. Symptoms may be seasonal.
monly found. Left atrial to aortic ratio is usually >2.0.
Chylous effusion.
Left ventricular size may be normal to mildly dilated (LV ● A murmur may not be present. In most cases, car-
end-diastolic dimension up to or above 16 mm). diac disease is not present. The most common
clinical sign is dyspnea, increased respiratory rate
Systolic function is normal or mildly decreased (nor-
and lethargy.
mal FS is between 35–55%)
Neurological disease causing collapse or hindlimb
Right ventricular dilatation may be seen (RV end-
paralysis.
diastolic dimension > 7 mm)
● Cardiac signs are usually absent, however a full car-
Hyperechoic endocardium and/or myocardium are diac work-up may be warranted to rule out the pres-
frequently observed. ence of silent heart disease. Neurological disease
Focal areas of myocardial hypertrophy bordering usually is not associated with alterations of periph-
areas of myocardial thinning are seen which probably eral systemic perfusion.
represent myocardial infarction.
Treatment
The mitral inflow profile is recorded at the tips of the
mitral valve from the four-chamber left parasternal Asymptomatic cat.
view. It commonly shows increased early inflow veloc- ● Angiotensin-converting enzyme inhibitors