Murmurs in Dogs and Cats Flashcards
Mitral Valve Disease / Valvular endocardiosis/ Myxomatous mitral valve disease
- pathophysiology
- predisposition
- history
- clinical findings
- diagnostics
- treatment
Valve leakage : Volume overload LV : Eccentric hypertrophy LV : Decreased cardiac output : Stimulation of the RAAS : Left CHF
LHS CHR :
- Cough/ tachypnoea/dyspnoea
- Exercise intolerance
- Pulmonary hypertension : RHS CHF
Predisposed:
- small breeds
- males > females
history: -Asymptomatic -Signs of left sided CHF Cough Dyspnoea Exercise intolerance - +/- signs of right sided CHF Ascites Dyspnoea due to pleural effusion
Clinical findings
- Systolic murmur over mitral +/- tricuspid valve
- Murmur grade related to severity of disease
- Early stages good myocardial function and good pulse quality
- +/- dyspnoea
- +/- ascites
- +/- arrhythmias
Diagnostics:
-radiographs:
early: cardiomegaly & airway compression
Later: CHF & pulmonary oedema
-echo: evidence of thickened valve and remodelling, end up with regurgitation
Treatment:
- depends on stage (look at tableO
Bacterial endocarditis
- pathophysiology
- presentation
- diagnosis
- treatment
- prevention
Pathophysiology:
- Affects valves on left side of the heart
- Aortic valve most common site in the dog
- Mitral valve second most common site
- Aortic stenosis predisposes to development of endocarditis
Typically present with:
- Pyrexia
- Joint stiffness
- New left sided murmur
Diagnosis
- Blood culture
- Urine culture
- Joint tap
- Echocardiography
- Abdominal ultrasonography
- Haematology
Treatment
-ABs
-supportive therapy
Prognosis is guarded
Prevention
-Treat dogs with severe aortic stenosis with prophylactic antibiotics if undergoing routine dental treatment or if they have wounds.
Dilated cardiomyopathy in dogs
Primary Aetiology
- Idiopathic
- Hereditary
Secondary Aetiology:
- Toxic – doxorubicin
- Taurine deficiency
- Carnitine deficiency
- Tachycardia induced
Systolic failure causes:
- Poor CO (exercise intolerance) : Stimulation RAAS : Fluid retention : Left +/- right sided CHF
- dilate LV : ventricular arrhythmias : syncope/death
Predisposition:
- Medium - large breeds
- Usually middle age – older
- Males > females
History:
- Forward failure : Exercise intolerance
- LHS CHF (Cough, dyspnoea, tachypnoea, exercise intolerance)
- RHS CHF (Pleural effusion, Ascites)
- Syncope : Ventricular arrhythmias (Boxer, Doberman, Great Dane)
- Asymptomatic ( occult or early form)
Physical findings:
Forward failure Pallor Poor capillary refill time Weak pulse Tachycardia
Backward (Congestive) heart failure
Tachypnoea/Hyperpnoea/dyspnoea – left sided CHF
Hepatomegaly, ascites – right sided CHF
Arrhythmias
Gallop sounds
Low grade systolic murmurs over mitral +/- tricuspid valves
Diagnostics:
-radiography: LA enlargement, LV enlargement, +/- signs of CHF, RHS CHF causing pleural effusion
Treatment:
Improve systolic function:
- Pimobendan, digoxin, dobutamine
- Decrease preload
- Diuretics (furosemide, spironolactone), ACE inhibitors (benazepril)
Decrease afterload:
-ACE inhibitors, inodilator (pimobendan)
Treat arrhythmias:
- Atrial fibrillation – digoxin, calcium channel antagonists (diltiazem), beta-blockers (atenolol)
- Ventricular arrhythmias – mexilitine, beta-blockers (atenolol), potassium channel blockers such as sotalol
Prevent further remodelling
-ACE inhibitors, pimobendan. spironolactone
OCCULT DILATED CARDIOMYOPATHY IN DOGS
Dilated cardiomyopathy may be present in a hidden or ‘occult’ form for several years before CHF develops
Irish wolfhounds, Newfoundlands typically just have slow atrial fibrillation
Boxers & Doberman Pinschers may just have ventricular arrhythmias
Some breeds such as Newfoundlands may have dilated poorly contractile left ventricles
Treatment:
-Arrhythmias – treat life threatening ventricular arrhythmias
sotalol, mexilitine
-Arrhythmias – treat fast atrial fibrillation > 160bpm
digoxin, diltiazem, atenolol
Hypertrophic cardiomyopathy in cats (HCM)
Aetiology:
- Systemic Hypertension
- Hyperthyroidism
pathophysiology:
- Concentric hypertrophy of LV : Poor relaxation : Diastolic failure : LA enlargement : Left sided CHF
- LA enlargement: thromus : HQ paresis
History:
- asymptomatic
- dyspnoea/tachypnoea
- lameness
- syncope
- inappetance
- lethargy
- ascites
CS:
- Murmur
- Arrhythmia (brady or tachy)
- Dyspnoea/tachypnoea
- Paralysis of back legs
- Enlarged thyroid gland if hyperthyroid
- Retinal changes if high BP
Diagnostics:
- Radiography: Cardiomegaly, vascular congestion, pulmonary oedema, pleural effusion
- ECG: ectopic beats, atrial fibrillation
- retina exam
- blood tests: Kidney function, Thyroid function, Biomarkers (Troponin I & NT-proBNP), Genetic tests
Treatment: SECONDARY: -Hyperthyroidism Medical Surgery Radioactive Iodine -Systemic Hypertension amlodopine +/- benazepril
PRIMARY:
Treat causes of secondary hypertrophy
Decrease workload: Calcium channel antagonists (diltiazem), betablockers (atenolol)
Improve relaxation: Calcium channel antagonists (diltiazem)
Decrease heart rate: Calcium channel antagonists (diltiazem), betablockers (atenolol)
Decrease preload if in CHF : Diuretics (furosemide), ACE inhibitors (benazepril)
Prevent thrombus formation: Aspirin, clopidogrel, dalteparin (low molecular weight heparin)
Feline Aortic Thromboembolism
Present with severe pain & paresis
Treatment
- Pain relief - opioids
- Anticoagulant – heparin/dalteparin
- Circulatory support – i/v fluids
- Treat cardiac disease
- Monitor ECG and potassium
PROGNOSIS: Poor
Dilated Cardiomyopathy in cats
- caused by taurine defiencey
- present same as HCM
- treat same as HCM + taurine supplement
Restrictive cardiomyopathy in cats
- walls are thin and stiff
- treat same as HCM
- prognosis worse than HCM
Myocarditis
May be secondary to toxoplasmosis, neospora, parvo-virus, ehrlichia, borrelia, neoplasia
- Arrhythmias common
- May develop poor systolic function and secondary dilation with low grade murmurs
- May develop CHF
Diagnosis: difficult, high serum troponin 1
Treatment:
- Treat primary disease
- Treat arrhythmias
- Treat CHF if present
Prognosis guarded – acute death common
