Cardiology Flashcards
Give 6 negative prognostic factors in structural heart disease.
○ Progressive chamber remodelling- dilated and altered chamber shape
○ Chamber dysfunction
○ Great vessel enlargement
○ PHT
○ CHF
Potentially dangerous arrhythmias
Give the 8 instances where echocardiography is recommended
- A previously diagnosed ‘functional’ murmur that is louder on serial examination
- A grade >3 left sided murmur compatible with MR or AR
- A grade >4 right sided murmur compatible with TR
- A suspected VSD or other congenital heart lesion
- Continuous or combined systolic/diastolic murmur
- Clinically important arrhythmias, even in the absence of a murmur
- Suspected myocardial injury
- Suspicion of CHF
What 2 factors should be incorporated into an exercising ecg?
Work intensity should be at or slightly exceeding the horse’s customary activities
Should include some method of stimulating unexpected sympathetic stimulation
What 4 specific measurements should be incorporated into an exercise test?
- Effects of exercise on auscultation (HR, rhythm, murmurs)
- Peak HR during exercise
- HR and rhythm during different phases of exercise and recovery
- Optional: Echo before and after exercise (stress echocardiography)
Describe a typical MR murmur
Mid-late systolic or holo/pansystolic left sided
Give 6 Underlying lesions that may be responsible for MR
Mitral valve dysplasia
Degenerative or inflammatory valve thickening.
Prolapse= MVP
Thickened or ruptured chordae tendinae= RCT
Flail leaflet
Secondary to valve annulus or ventricular dilatation in severe AR, non-restrictive VSD or, rarely, cardiomyopathy.
What secondary changes occur in severe MR?
PHT and enlargement of the LA and LV
In the absence of PA catheterisation, what measures can be used to estimate PHT?
TR velocity and PA diameter
Why is assessment of LV function difficult in MR?
increased preload and reduced afterload.
What changes occur to LV function in acute/severe MR disease?
LV hyperdynamic: increased FS, dynamic compression of the RV and exuberant septal motion
What changes occur to LV function in chronic MR disease?
progressive remodelling and LV dysfunction. -> reduced FS to within or below normal range
What kind of MR jet is often under-estimated?
An MR jet that is eccentric, wall hugging or flat
What are the major negative prognostic indicators for MR?
○ Moderate-severe regurgitation
○ Endocarditis
○ RCT
○ Flail leaflet
○ Severe valvular thickening
○ Concurrent PA dilation
○ Increased TR velocity
○ Significant MR with AF or tachycardia
What is the most common cause of AR?
degenerative valve thickening and/or AV prolapse
Give 7 less common causes of AR
Congenital malformations
Leaflet tearing
Endocarditis
Valvulitis
Fenestrations
Aortic root disease
In association with VSD.
describe the AR murmur
left sided holodiastolic
What is the most common structural change of the AV associated with AV, as visible on 2D echocardiography?
thickening as a fibrous band-like lesion appearing as an echoic line parallel to the free edge if the left coronary leaflet
Which AV leaflet is most commonly affected in AR?
left coronary leaflet
What does premature closing of the MV on M-mode indicate?
markedly increased LV end diastolic pressure= severe AR.
Why may the MV not fully open in AR?
Eccentric jets directed towards the MV can prevent full MV opening.
Why may the MV flutter in AR?
Diastolic fluttering of the mitral or aortic valves, aortic root or IVS if the jet is directed towards these structures.
What does LA enlargement indicate in AR?
ventricular dysfunction, volume retention or concurrent MR
Give 3 as yet unvalidated measurements of AR severity
regurgitant signal duration, pressure half time, velocity time integral of AR compared to forward flow.
Above which pulse pressure is AR progression more likely?
60mmHg
When is echocardiography of a suspected TR indicated?
grade 4/6 or louder
Poor performance
Concurrent thrombophlebitis
With fever of unknown origin
PPE
Give 3 findings that would indicate a TR was benign/ training related
Valve is structurally normal
RA and RV are normal in size
Regurgitant jet is thin and directed towards the aorta
Above which TR velocity should you suspect PHT?
3.5m/s
Give 3 findings on echo that would indicate a TR was clinically significant.
Structural or motion abnormalities in the TV
RA and RV enlargement
Jet is wider at origin and occupies a larger area in the RA (often central or towards the RA wall).
In which breeds is VSD predisposed?
- Welsh sec A, Standardbreds and Arabians over-represented
Describe the typical VSD
peri membranous, located ventral to the tricuspid leaflet and below the junction of the right and non-coronary cusps of the aortic valve.