Cardiology Flashcards

1
Q

Possible heart sounds in horse

A
2 to 4
S1 - lub = closure of AV valves
S2 - dub = closure of semilunar valves
S3 - ahh = end of rapid filling phase
S4 - ba = atrial contraction
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2
Q

ECG

A

cannot perform typical vector analysis because Purkinje fibers deeply penetrate myocardium and do not polarize apex to base, more wringing action
Main ECG lead placement is base apex because maximizes depolarization
Normal variants
- notched P wave common
- negative QRS (intervetricular septum depolarization)
- large T wave

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3
Q

preferred method of evaluating equine heart

A

echocardiography

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4
Q

normal HR

A

26-44bpm

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5
Q

_______ predominates at rest in the horse

A

vagal tone

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6
Q

ECG lead placement

A

+ on left thorax
- on right jugular furrow
ground at any point remote form heart

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7
Q

Most common PHYSIOLOGICAL arrhythmia in the horse

A

Mobitz I 2nd degree AV block = Wenkebach

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8
Q

Most common pathological arrhythmia in the horse

A

Atrial fibrillation

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9
Q

is Mobitz Type II always pathologic?

A

yes

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10
Q

Presenting complaint of horse with Afib

A
exercise intolerance (quitting at 3/4post, pulling up)
tachypnea
EIPH
CHF
collapse
myopathy, colic
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11
Q

2 forms of Afib

A

paroxysmal - occurs during race and can disappear with deceleration of the HR
- may be associated with K depletion in horses given furosemide or oral bicarb pre-race

Sustained - easier to Dx because rhythm sustained over long period of time

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12
Q

PE of horse with A fib

A

auscultation - irregularly irregular, sounds like shoe in drier
pulses - variable strength

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13
Q

ECG of an Afib horse

A

baseline fibrillation wavs (F waves) = soars or fine
QRST usually normal morphology but irregularly spaced

NO P WAVES

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14
Q

Treatment of Afib

A

If HR and echo normal –> give Quinidine

If HR high or abnormal echo –> Digoxin then Quinidine

If HF –> don’t Tx the Afib, Tx the HF

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15
Q

MOA of Quinidine as Tx for Afib

A

blocks fast inward Na current in myocardium

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16
Q

How do you Tx quinidine toxicity

A

Tx acute toxicity w. IV sodium bicarbonate

17
Q

Idiosynchratic rxn to quinidine

A

causes rapid supra ventricular tachycardia

18
Q

Dosing Quinidine

A

if acute <72h, can use IV
- give small bolus Q 10 min, do not exceed 12mg/kg

More typically, use PO quinidine
can use 5mg test dose, then 20-22mg/kg q2h until converted
stop if toxic side effects, or reach 60g

19
Q

Ventricular tachycardia

A

associated with metabolic disease

caused by myocarditis, endotoxemia, hypoxia, electrolyte disturbances

20
Q

Clinical signs of VT

A

exercise intolerance, can lead to syncope

21
Q

Treating VT

A

LIDOCAINE, bolus or infusion

indicated in sick colicy patients

22
Q

Pathological murmurs in the horse

A

mitral insufficiency - systolic murmur on L side
aortic insufficiency - diastolic murmur on L side
tricuspid insufficiency - systolic murmur on R side

23
Q

most important murmur in the horse

A

mitral insufficiency

24
Q

clinical signs of mitral insufficiency

A

vary depending on severity of valvular dysfunction
most likely valvular dysfunction leading to cardiac failure
mild: exercise intolerance
severe: sudden death, chord tendinae rupture, acute decompensation in failure (most common cause of valvular death in horses)

25
Most common site of bacterial endocarditis?
mitral valve
26
Diagnosing mitral valve insufficiency
LA and LV size, regurgitation fraction, PA size may hear murmur if severe may show Afib because enlarged atria
27
most likely to lead to HF
mitral valve insufficiency
28
if have mitral valve insufficiency and chord tendinae rupture, murmur sounds like
honking murmur like geese
29
if pulmonary artery ruptures
sudden death
30
Aortic insufficiency
seen in older horses noisy musical diastolic murmur, mostly on L side incidental finding but can lead to failure
31
Prognostic factors of valve insufficiency
type of valvular disease degree of L sided volume overload size of regurgitant jet age of horse Mitral: size of PA Aortic: size of aortic root, presence/absence of concurrent L AV insufficiency
32
Vegetative endocarditis
mitral valve more commonly young horses, males more than females endothelial damage --> bacteria can adhere --> local clotting activated CS: fever of unknown origin, tachycardia, murmur, poor doing colic (from ileus from perfusion problems) Dx: CBC (inflammation), Chem (organ dysfunction from CV compromise), blood culture to isolate organism Tx: 4-6w of antimicrobials minimum, anti inflammatories (aspirin or flunixin) to help w/ clotting
33
Follow up protocol for endocarditis
blood culture 60d after cessation of antibiotics | at least 3 cultures
34
3 important causes of HF
mitral valve insufficiency pericarditis ionophore toxicosis
35
3 forms of pericarditis
effusive - usually viral constrictive (fibrinous) - usually bacterial, pleuropneumoniae combined
36
clinical signs of pericarditis
FEVER, edema, distended jugular veins, poor pulses, weakness, listlessness, syncope, acute developing failure
37
Tx pericarditis
Effusive - drainage Constrictive - pericardectomy ``` HF drugs diuretics - furosemide inotropes - digoxin ACEi - enalepril vasodilators - hydralazine ```