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41 Cards in this Set
- Front
- Back
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Valvular endocardiosis |
Myxomatous degeneration of the heart valves, affecting mitral and tricuspid valves, leading to their incompetence |
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Breed and sex predisposition |
CKC spaniel, poodles, males |
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Clinical signs |
Systolic murmur over mitral and tricuspid valves.
Starts off as low grade left apical systolic murmur but grade increases, as does duration to become pan systolic Mitral murmur moves over to right side of heart Coughing due to large left atrium pressing on bronchi Exercise intolerance May present with incidental murmur or left sided or biventricular heart failure |
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Radiography |
Left atrial and ventricular enlargement Severe mitral insufficiency Right atrial and ventricular enlargement Severe tricuspid insufficiency Check pulmonary veins and lung fields for congestion or oedema Generalised cardiomegaly |
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Electrocardiography |
P waves - wide - left atrial enlargement or - wide and tall - left and right atrial enlargement R waves - frequently tall and wide due to left ventricular enlargement Tall R waves, wide QRS and deep Q wave indicative of biventricular enlargement May be sinus tachycardia |
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Echocardiography |
Thickened valves may be visualised Chamber enlargement Doppler ultrasound |
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Treatment |
Depends on class of failure: Frusemide, ACE inhibitors, pimobendan Additional diuretics may be needed or digoxin for sinus tachycardia or atrial fibrillation |
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Prognosis |
Guarded once heart failure develops |
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Cause of bacterial endocarditis |
Systemic bacteraemia - septic emboli will seed off |
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PATHOphysiology |
Valvular incompetence or stenosis |
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Valve affected in cows compared to dogs and cats |
tricuspid - emboli to lungs D and c - emboli to joints and kidneys |
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source of bacteria for dogs |
often periodontal disease |
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Presenting signs
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Variable: Lameness Lethargy Fever Haematuria Dyspnoea |
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Clinical findings |
Pyrexia most common Shifting lameness if septic arthritis New murmur - systolic or diastolic |
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Radiography |
Non-specific findings |
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Electrocardiography |
Non-specific findings Myocardial emboli or myocarditis may cause arrhythmias |
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Echocardiography |
Vegetative lesions may be seen Valvular lesions may lead to insufficiency/stenosis which will be apparent with Doppler |
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Diagnostic tests |
Haematology for positive bacterial infection via culture 3 samples in 24 hours May do urine sample and culture |
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Treatment |
Antibiotics for 4-6 weeks Often parenteral followed by oral |
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Prognosis |
Guarded |
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Approach to patients with left-sided congestive heart failure |
If stable - definitively diagnose and treat underlying cause If critical - make stable by: oxygenation, cage rest, sedation if necessary, preload and after load reduction then make definitive diagnosis |
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Approach to patients with right-sided congestive heart failure |
If stable obtain definitve diagnosis If large pleural effusion -> thoracocentesis Abdominocentesis usually left only for diagnosis unless interfering with ventilation (because you will deprive animal of protein) Once stable find definitive diagnosis and treat accordingly |
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Principles of long term treatment |
Treat primary underlying cause Preload and after load reduction Positive inotrope Improve diastolic filling Correct rhythm - brady/tachyarrhythmias |
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Preload definition |
Volume of blood filling ventricles at end of diastole |
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Afterload definition |
Pressure left ventricle must overcome to circulate blood |
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Preload reduction methods |
Loop diuretics Thiazide diuretics Potassium-sparing diuretics ACE inhibitors Vasodilators |
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Loop diuretics |
Frusemide - diruetic and natriuresis May cause dehydration, pre-renal azotaemia, hypokalaemia and hyponatraemia and may stimulate RAAS IV frusemide is vasodilatory so can be used to decrease preload in this way |
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Thiazide diuretics |
Hydrochlorthiazide, chlorthiazide Diuretic and natriuresis - sodium depletion if used with loop diuretic |
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Potassium-saring diuretic |
Spironolactone - spares potassium, slow acting and cannot be used on its own but with ACE inhibitors and other diuretics |
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Venodilators (rhea) |
Glyceryl trinitate -useful for cardiogenic pulmonary oedema - absorbed through skin - short term Frusemide IV |
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ACE inhibitors (pril)
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Enalapril, benazepril, imidipril, ramipril - Hyperkalaemia is possible (careful with potassium sparing diuretics and potassium supplementation) Enalapril - renal excretion so |
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Afterload reduction
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Arteriodilators ACE inhibitors Inodilators |
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Arteriodilators |
Hydralazine - mitral valve insufficiency, May cause hypotension and reflex tachycardia Large tablet hard to administer in small dogs and cats |
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Inodilators |
Pimobendan - positive inotrope, vasodilator, no compensatory tachycardia |
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Treating systolic failure |
Calcium sensitizer/inodilators Cardiac glycosides Beta agonist |
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Calcium sensitizer/inodilator |
Pimobendan - beneficial for dilated cardiomyopathy and myxomatous valve disease |
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Cardiac glycoside
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Digoxin Weakly positive inotrope and used to control ventricular rate in ventricular fibrillation Maintenance dose Stop use if: anorexia, nausea, GI signs, arrhythmias Decrease for obese dogs, fluid retention, dobermans, renal failure Long half life in cats so use with caution |
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Beta agonist |
Dobutamine IV, severe myocardial failure |
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Treating diastolic failure |
Depends on underlying cause Drain pericardial effusion Improve ventricular relaxation Slow heart rate and thus increase filling time Decrease contractility and thus myocardial O2 consumption |
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Calcium channel antagonists |
Diltiazem - lusitropic, negative inotrope and chronotrope |
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Beta blocker |
Propanolol Reduce heart rate so increase filling time and cardiac work Negative inotrope |
