Acquired Feline Cardiac Diseases Flashcards
Cardiomyopathies seen in cats.
Hypertrophic cardiomyopathy / HOCM.
Restrictive cardiomyopathy.
Unclassified cardiomyopathy.
Characteristics of cardiomyopathy in cats.
Increased ventricular stiffness - diastolic dysfunction.
Good / adequate systolic function.
L atrial dilatation - due to increased atrial pressures, causing left sided CHF.
- can cause thromboembolism due to increase blood turbulence in the L atrium.
Pulmonary oedema due to L sided CHF:
- pleural effusion, pericardial effusion.
- What is seen in the heart in a cat with hypertrophic cardiomyopathy?
- Breeds affected by HCM.
- Genetics associated with HCM.
- L ventricular concentric hypertrophy as a primary heart disease that is localised the the base of IVS or generalised.
- Maine Coon, Ragdoll, Norwegian Forest, most commonly is the DSH.
- A mutation of myosin binding protein C.
Incomplete penetrance (can have mutation w/o disease).
What must be done before making Dx of HCM?
Exclude other causes of LV hypertrophy.
- systemic hypertension.
- hyperthyroidism.
- acromegaly.
- dehydration – pseudohypertrophy.
- (aortic stenosis)
Restrictive cardiomyopathy.
- Increased ventricular stiffness, w/ normal myocardial thickness.
- Myocardial and endomyocardial forms.
- Replacement fibrosis.
- Increased filling pressures, left atrial or bi-atrial dilation.
Predisposing factors for arterial thromboembolism.
- L atrial dilatation.
- Endothelial disruption.
- Sluggish blood flow.
- Hypercoagulability.
- Aortic bifurcation: hindlegs, R front leg.
- Prevalence of cardiomyopathy in healthy cats.
- % cats with a murmur.
- % cats w/ murmur w/o heart disease.
- % cats with heart disease w/o a murmur.
- Relationship between murmur and disease.
- 15%.
- 41%.
- 70%.
- 18%.
- Louder the murmur, the higher the likelihood of disease.
Presentations of cats with heart disease.
- No clinical signs.
- Heart murmur, gallop.
- Arrhythmia, syncope.
- No signs, then go into CHF after procedure, fluids, sedation.
- Sudden paresis/paralysis/pain (thromboembolic).
- HR of cat in CHF.
- Respiration of cat in CHF.
- Pulses of cat in CHF.
- Tachycardia.
Bradycardia - severe. - Tachypnoea, dyspnoea.
Pulmonary oedema, pleural effusion. - Weak peripheral pulses.
Arterial thromboembolism presentation.
- Might be first sign of cardiac disease.
- Sudden onset lameness, paresis.
- Painful in the beginning.
- No peripheral pulse.
- Cold extremity, swollen.
- Cyanosis.
Five Ps of arterial thromboembolism.
- Pain.
- Paresis.
- Pulselessness.
- Pallor (or cyanosis).
- Poikilothermy (cold).
Diagnostic tests for cardiac disease in cats.
- Thoracic radiographs – ID CHF, pleural effusion.
- Lung ultrasound – good to avoid distress in first instance.
- Echocardiography – Dx.
- Cardiac biomarkers – Probability of heart disease.
- ECG – arrhythmia.
- Blood pressure – ID hyper- or hypotension.
- Blood tests – Biochemistry, T4.
Thoracic radiographs.
VHS:
- <8.0 for screening – heart disease unlikely.
- >9.3 specific – heart disease likely.
Enlargement of heart seen better in DV position.
Pulmonary oedema – could be anywhere w/in the lungs.
Pleural effusion.
Echocardiography.
Measure wall thickness.
Up to 5.5mm normal.
>6mm abnormal.
See ‘smoke’ = sluggish blood flow with platelets sticking together. Can be seen in the L atrium.
HOCM.
Dynamic obstruction of the left ventricular outflow tract.
Systolic anterior motion of the mitral valve towards the septal wall.
Also get mitral regurgitation of blood back into the atrium as AV valve is not closing properly.
May be due to the mitral valve being longer than it should be or may be due to the septal wall being thicker than it should be.
Causes hypertrophy of the ventricle.
