Lecture 15 9/19/24 Flashcards
What is the most common form of acquired heart disease in cats?
myocardial disease
What are the specific causes associated with feline myocardial diseases?
-thyrotoxic
-hypertensive
What are the characteristics of HCM in cats?
-hypertrophy of a non-dilated ventricle occurs in the absence of hyperthyroidism or systemic hypertension
-heritable in maine coon cats and ragdoll sphinx cats
-familial in other purebred cats
What is the pathophysiology of HCM?
-systolic ventricular performance is usually normal or hyperdynamic
-characterized primarily by diastolic dysfunction
-increased wall thickness results in increased chamber stiffness
-hypertrophy may outstrip coronary perfusion and delay relaxation
What is diastolic function?
ability of ventricles to fill in the absence of a pathologic increase in pressure
What does diastolic function depend on?
-myocardial relaxation
-compliance
What are the steps of diastolic dysfunction?
-prolonged relaxation leads to reduced compliance
-reduced compliance leads to an increase in the diastolic pressure/volume relationship
-abnormal relationship leads to low output and congestive signs
What causes increased venous and LA pressure?
hypertrophic left ventricle does not want to accept diastolic vol.
What is a suggestive finding of diastolic dysfunction on echo?
atrial dilation that is disproportionate to ventricular volume
What are the characteristics of systolic anterior motion of the MV?
-mitral valve leaflets move cranially during systole
-may cause dynamic obstruction of the left ventricular outflow tract, MR, and murmur
-not a therapeutic target and not important for prognosis
What is the signalment for feline HCM?
-male predisposition
-seen in virtually any age
What is the clinical presentation of feline CMs?
-incidentally detected murmur/gallop
-clinical signs related to CHF and systemic thromboembolism
-possible sudden cardiac death
What are the characteristics of murmurs in cats?
-normal cats sometimes have murmurs as a result of dynamic phenomena
-changes in murmur intensity is not prognostically relevant
-murmurs are more common in cats with subclinical CM that in cats with HF
What are the findings associated with feline CM?
-LA dilation
-gallop sounds
-extreme LV hypertrophy
-spontaneous echo-contrast or intracardiac thrombus
What are flow/innocent murmurs?
soft murmurs that vary in intensity with heart rate; common in healthy, echo-normal cats
How is heart disease diagnosed in cats on rads?
-pleural effusion in the absence of ascites is a common manifestation of heart failure
-pleural effusion complicates diseases that affect the left ventricle
How is HCM diagnosed in cats?
echo evidence of hypertrophy of a non-dilated ventricle in the absence of hyperthyroidism or systemic hypertension
What are the characteristics of stage B heart disease diagnosis in cats?
-T4 should be measured in cats older than 6-7 years of age; hyperthyroidism can cause mild, reversible myocardial disease
-echo
-systemic BP measurement
-possible thoracic rads
Which cats should receive a cardio. workup?
-those with suspicious history/physical exam findings
-older patients subjected to interventions such as anesthesia or IV fluid therapy
What are the characteristics of treating stage B2 heart disease in cats?
-no agent shows efficacy in delaying clinical signs/slowing disease progression
-clopidogrel is reasonable if moderate/marked LAE present
What are the unique aspects of feline heart failure presentation?
-very rarely cough
-sudden onset of clinical signs
-tachycardia is not a consistent feature
-acutely decompensated heart failure is “cold and wet”
How can acutely decompensated heart failure be diagnosed in cats?
-findings of tachypnea, hypothermia, and or gallop sounds
-thoracic ultrasound and/or BNP testing if rads cannot be obtained
What are the characteristics of acutely decompensated HF treatment?
-empirical therapy often indicated
-provide O2, sedation, and warming
-diuretic therapy
-thoracocentesis to relieve pleural effusion
-pimobendan for cases with low cardiac output
-IV FLUIDS CONTRAINDICATED
What are the characteristics of stage C heart disease therapy in cats?
-no agent superior to placebo in studies, but enalapril appears best
-atenolol may harm cats if HF is diastolic
-spironolactone may have positive effects
