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
What are the characteristics of pimobendan use in cats?
-administration seems to be tolerated
-can be considered when systolic dysfunction is present
-SAM presence is a contraindication
How is stage C HF treated at home in cats?
-furosemide
-clopidogrel
-possible ACE inhibitor
What are the characteristics of feline arterial thromboembolism?
-patients with myocardial disease are predisposed to development of intra-cardiac thrombi
-thrombus often develops in left atrial auricle
What clinical signs are seen with embolization of the caudal aorta?
-pain
-paresis/paralysis
-absent arterial pulse
-peripheral cyanosis
What is the prevalence of FATE?
-occurs in 10% of cats with echo. identified myocardial disease
-first indication of heart disease in over 80% of affected patients
What are the risk factors for FATE?
-left atrial enlargement***
-possibly systolic dysfunction
-possibly spontaneous echo. contrast
What is the therapy for FATE upon acute presentation?
-narcotic analgesia
-short-term anticoagulation
What is “primary prevention” thromboprophylaxis?
use of clopidogrel with the intension to prevent future thrombi events in at risk patients
What is “secondary prevention” thromboprophylaxis?
use of clopidogrel with the intension to prevent reoccurrence of thrombi
What is the prognosis of FATE?
generally poor, with a mortality of 30% during initial hospitalization
What is the prognosis of feline HCM?
-highly variable
-cats with CHF have poor prognosis
-cats with mild disease can live for years
-atrial size is most important risk factor for poor outcome
What are the characteristics of restrictive cardiomyopathy?
-atrial dilation with normal ventricular dimensions and wall thicknesses
-systolic ventricular performance is normal
What are the characteristics of right ventricular arrhythmogenic cardiomyopathy in cats?
-fatty or fibrofatty replacement of right ventricular myocardium
-arrhythmias
-marked right ventricular dilation
