Murmurs Flashcards
Grade III/VI or less left heart base systolic ejection murmur
Functional (physiological murmur)
What is a functional murmur?
Associated with rapid ejection of blood in early systole
What is the most common congenital cardiac defect in the foal?
Ventricular septal defect
T/F: often ventricular septal defects are incidental findings on physical exam
True
Or can present for poor performance and exercise intolerance
Pan-systolic murmur, grade III-IV/VI with the PMI at the 3rd or 4th ICS
Murmur can be heard on the right, one grade higher than the left
Ventricular septal defect
Why is VSD often associated with a grade III-IV murmur over the left heart base ?
Increased flow over the pulmonic valve —> relative pulmonic stenosis .
What is the prognosis for a VSD?
If 2.5cm or less —> usually normal growth and performance
Larger VSD—> volume overload to the left heart and poor growth and performance
Murmur grade II-IV/VI with continuous (systolic/diastolic) machinery murmur with PMI in the dorsal left 4th ICS
Patent ductus arteriosus (PDA)
When is a PDA murmur not pathologic?
If heard in the first 72-96hours of birth
Closure of the ductus arteriosus is triggered by?
Increased arterial O2 tension and decreased flow
—> occurs initially by vascular constriction followed by muscular and fibrosis
What kind of shunt is present in a PDA?
L to R shunt
In foals, the ductus arteriosus can appear to close but can reopen due to?
Systemic illness or hypoxia
—> until fibrosis the ductus is only closed by vasoconstriction and can be reopened
Clinical signs associated with mitral valve insufficiency?
Exercise intolerance
Weight loss
Signs of CHF (tachycardia, jugular vein distention, resp distress, SQ edema, and ascites)
What is the most common cause of mitral valve insufficiency?
Degenerative changes to valve
Also the most common site for bacterial endocarditis
Severe damage of the mitral valves or leaflets can result in spontaneous rupture of??
Chordae tendinae
Grade III or greater, holosystolic/pansystolic murmur with PMI at 5th ICS
Mitral valve
If a mitral valve murmur is associated with chordae tendinae rupture, how will the murmur sound?
Extremely loud honking murmur
When do you have a poor prognosis associated with mitral valve insufficiency ?
More sever valve dysfunction —> leads to progressive CHF
Presence of dilated pulmonary artery (unsafe to ride)
T/F: aortic valve insufficiency is usually asymptomatic
True
Large regurgitation due to aortic insufficiency can lead to volume overload of the ________
Left ventricle
What is usually the cause of aortic insufficiency ?
Degenerative changes to aortic valve
—> nodules, fibrous bands and plaques
Grade II-IV/VI pan-, holo-, diastolic murmur with PMI at 4th left ICS
Aortic insufficiency
What breed is predisposed to tricuspid insufficiency?
Thoroughbreds
Clinical signs associated with tricuspid insufficiency?
Exercise intolerance (RARE)
Pathological changes at this valve are uncommon, common site for physiological regurgitation
What is the prognosis for tricuspid insufficiency ?
Good prognosis for continued performance
Poor if accompanied by atrial fibrillation as typical reflects concurrent severe mitral insufficiency
Right sided holo-, pan-systolic murmur
Tricuspid insufficiency
What valves are most commonly affected by vegetative endocarditis ?
Mitral and aortic
What is the pathogenesis of vegetative endocarditis?
Structural damage to the endothelium —> formation of microscopic thrombi along valvular surface
Fibrous clot formation/vegetation’s
What are hemodynamic causes of endothelial trauma?
Regurgitant jets
Narrow orifices
High pressure gradients
Sepsis of the valve
Adhered bacteria grow in laminar network of fibrin
Local release of thromboplastin activates coagulation (extrinsic pathway)
Clinical signs associated with vegetative endocarditis ?
Fever of unknown origin (FUO) Intermittent or continuous fever Tachycardia, tachypnea Cardiac murmur —> systolic if AV valves —> diastolic if semilunar valves
What diagnostics can you do to confirm vegetative endocarditis?
Chem
- hyperproteinemia (hyperglobulinemia and hyperfibrinogenemia)
- leukocytosis
- non-regenerative anemia (typical of chronic dz)
Blood culture
ECG
Echo —> affected valve leaflets is thickened, irregular, with globular hyperechoci mass on free edge
What bacteria are most frequently the cause of vegetative endocarditis?
Strep sp, Actinobacillus equuli, and Ecoli
What arrhythmia is common if there is mitral valve insufficiency and LA enlargement due to vegetative endocarditis ?
Afib
What is the treatment for vegetative endocarditis?
Antimicrobial for minimum 4-6weeks
—> K-pen IV and gentamicin
Anti inflammatory
—> phenylbutazone or flunixin meglumine
—> aspirin (decrease platelet aggregation)
AF, cardiac failure, and VPC
—> digoxin if CO is compromised
—> diuretics to decrease volume overload
What is more common, left or right sided HR in the equine patient?
Horses will typically have signs of both, it is usual for the horse to quickly involve the other part of the circulation when one side fails
