Term
| Which physiologic changes in cardio are especially important with signalment? |
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Definition
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Term
| Which heart sounds do we hear in a horse? |
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Definition
-four
-always hear first two but can occasionally hear first three |
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Term
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Definition
| -sound made by slocure of AV valves |
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Term
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Definition
| -sound made by closure of semilunar valves |
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Term
| What is the significance of a marked split S2 in horses? |
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Definition
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Term
| What is S3? How often is it heard? |
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Definition
-caused by rapid filling of ventricles
-heard best over cardiac apex about 50% of time |
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Term
| What is S4? When is it heard? |
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Definition
-caused by atrial contraction
-can be heard in 2nd and 3rd AV block |
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Term
| What is the typical HR for a horse? What changes in how we take it in a horse? |
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Definition
-26-44 bpm
-listen for at least a minute |
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Term
| True or False: Arrhythmias are less common in horses than any other domestic species. |
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Definition
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Term
| When should we perform an ECG in a horse w/ an arrhythmia? |
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Definition
| -any time the arrhythmia does not disappear w/ excitement or exercise |
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Term
| What is the purpose of an ECG? |
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Definition
| -detects rate and rhythm changes: not useful for chamber size |
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Term
| Which ECG do we use in the horse? |
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Definition
-base-apex
-red net: red on right neck
-white on right: white on right withers
-black heart: black on left side above elbow
-set recorder to lead I |
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Term
| What are the parts of the ECG in a horse? |
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Definition
-P wave: biphasic due to atrial depolarization
-WRS: ventricular depolarization
-T wave: ventricular repolarization (should be positive) |
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Term
| What is sinus bradycardia? |
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Definition
| -sinus rate < 26 bpm due to high vagal tone at rest |
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Term
| When is sinus bradycardia benign or pathologic? |
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Definition
-Benign: rate should inc w/ exercse, excitement, parasympatholytics
-Path: assoc w/ severe exercise intolerance and syncope |
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Term
| What does sinus bradycardia look like on ECG? |
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Definition
| -normal complexes just really slow |
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Term
| What is the most common physiologic arrhythmia in the horse? |
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Definition
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Term
| When is a second deg AV block considered physiologic in the horse? |
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Definition
| -when it goes away w/ dec vagal tone |
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Term
| What does second deg AV block look like on ECG? |
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Definition
| -p wave w/out ARST w/ regular intervals b/n complexes & same pause interval |
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Term
| What is sinus tachycardia? When is it usually seen? |
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Definition
-sinus rate > 50 bpm
-often seen in nervous or excited horses common w/ underlying dz: sepsis, anemia, shock |
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Term
| What does sinus tachycardia look like on ECG? |
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Definition
| -normal complexes just really fast |
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Term
| How can we differentiate physiologic arrhythmias from pathologic? |
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Definition
-an ECG at exercise
-arrhythmia in combo w/ other issues is more likely to be pathologic |
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Term
| What is the most common pathologic arrhythmia in the horse? |
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Definition
-atrial fibrillation
-most common arrhythmia causing poor performance in young athletes |
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Term
| What is the most common presenting complaint w/ atrial fibrillation in horses? Others? |
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Definition
-exercise intolerance
-others: EIPH, dyspnea, syncope |
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Term
| Can atrial fibrillation be an incidental finding? |
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Definition
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Term
| What does atrial fibrillation sound like? |
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Definition
-irregularly irregular rhythm
-heart sounds vary in intensity
-lack of 4th heart sound |
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Term
| What does atrial fibrillation look like on ECG? |
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Definition
-irregular R-R intervals
-lack P waves, have lots of f waves
-variability in QRS-T cplx beat to beat |
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Term
| What are some common causes of atrial fibrillation? |
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Definition
-electrolyte distrurbances: low K+
-underlying cardiac dz and atrial enlargement
-myocarditis
-idiopathic large atrial size: MOST COMMON |
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Term
| When do we convert atrial fibrillation horse rather than not? |
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Definition
-if HR < 60 bpm
-short duration of onset
-no hx of myocardial pathology
-no CS of heart failure or structural changes in heart
-risk vs benefit |
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Term
| HOw do we convert atrial fibrillation in the horse? |
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Definition
-Quinidine
-electrical cardioversion: great but expensive
-make sure whole body K+ is WNL |
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Term
| What is the prognosis of atrial fibrillation in the horse? |
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Definition
-unwise to recommend working an untreated horse
-recommend exercise tolerance test w/ holter monitoring |
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Term
| What are the signs in horses w/ supraventricular tachycardia? |
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Definition
-very rapid rate
-significant dec in performance |
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Term
| What are some causes behind equine supraventricular tachycardia? |
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Definition
-systemic dz
-electrolyte & met disturbances
-myocardial dz |
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Term
| What does supraventricular tachycardia look like on ECG? |
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Definition
-short but REGULAR R-R intervals
-usually normal QRS-T complexes: can be wide and bizarre w/out visible P waves |
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Term
| How do we treat equine supraventricular tachycardia? Extra precautions? |
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Definition
-digoxin +/- quinidine
-if together do TDM: qhinidine can inc concentrations of digoxin |
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Term
| What does a 3rd degree block look like on ECG? |
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Definition
-QRS-T complexes normal or widened
-R-R interval is regular, P waves normal
-P waves not assoc w/ ARS-T complexes |
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Term
| What do VPCs look like on ECG? |
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Definition
-ARS-T usually bizarre
-T wave in opposite direction of QRS
-followed by a compensatory paus |
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Term
| What do VPCs usually indicate in horses? |
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Definition
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Term
| When are equine VPCs significant? |
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Definition
-inc in frequency w/ exercise
-multiform
-R on T |
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Term
| What is equine ventricular tachycardia? |
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Definition
-4 or more runs of VPCs w/ inc HR
-paraxysmal or sustained
-uniform or multiform |
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Term
| What is equine ventricular tachycardia usually associated w/? |
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Definition
| -assoc w/ severe changes in performance +/- syncope |
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Term
| What is a common cause of V-tach in horses? |
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Definition
| -endurance horses w/ electrolyte abnormalities |
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Term
| What does V-tach look like on ECG? |
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Definition
-4 or more runs of VPCs
-P waves present but not conducted
-inc HR |
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Term
| When do we treat equine arrhythmias? |
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Definition
-hemodynamic instability
-exercise intolerance
-poor performance
-heart failure
-dyspnea
-syncope |
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Term
| When do we treat ventricular arrhythmias in horses? |
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Definition
-SVT that worsens w/ exercise or results in HR > 200 bpm
-rapid SVT or ventrial arrhythmia at rest > 120 bpm
-frequent or multiform ectopic beats
-ventricular arrhythmias more often cause hemodynamic compromise, therefore they are more often treated |
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Term
| How do we treat v-tac in horses? |
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Definition
-lidocain
-if that fails use MgSO4 |
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Term
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Definition
| -lack of recognizable WRS-T complexes |
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Term
| What are the two more important question for general prognosis? |
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Definition
-is hte horse suitable for the kind of work for which it will be used?
-is the safety of the rider at risk? |
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Term
| What is the issue with condemning every horse that has a murmur or arrhytmia? |
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Definition
-unfortunate for a lot of horses
-not an educated approach |
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Term
| What do we use for an exercise tolerance exam in horses? |
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Definition
| -consider ah olter monitor or telemetry during exercise |
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Term
| What are the general guidelines for not recommending work for equine exercise tolerance test? |
|
Definition
-cery frequent premature contractions: guarded prognosis
-marked bradycardia w/ arrhytmia |
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Term
| Wat is the general prognosis for brood mares? |
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Definition
| -if CO is compromised, danger loosing foal & mare late term |
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