LA Dysrhythmia Flashcards

Question

What is going on here?

Answer 1

2nd degree AVB – normal Normal QRS with P and T Horse then decides after a consistent rate to have a P and no QRS Physiological – get a PQ interval getting longer and then horses block s Type 1 Sometimes if in right place you will hear a faint S4 otherwise you hear nothing for 2 r-r intervals

Answer 2

–Atrial fibrillation –Ventricular tachycardia –3rd degree AV block (this ECG) more common in donkeys but still rare –SV and V premature depolarising

Answer 3

* MOST IMPORTANT CARDIAC DYSRHYTHMIA IN THE HORSE * Lack of coordinated atrial electrical activity * Can be triggered by electrolyte/acid-base imbalances, anaesthetic and drug administration (that causes bradycardia), exercise * Rather than taking SAN – AVN. It goes round and round the same housing estate with escaping. Circuits setting off in the atria – wobble like jelly. Chances of it forming these circuits rather than the direct SAN - AVN – high vagal tone, low HR and big atria

Answer 4

•Horses particularly susceptible (esp large ones – TB’s, SB’s, Draught horses, trained). Athletic heart increasing the atria size. Also seen in cattle – reduction in milk yield and being a bit slow. Horses tend to only have CS at exercise (and only if they need their cardiac reserve) –Large atrial mass (more likely when enlarged with disease – MR/TR) –High vagal tone and low heart rate •No effect upon cardiac output at rest, only when exercised as atrial contraction only contributes 25% of CO

Answer 5

* None- most of the time * Exercise intolerance/poor performance – eventers, race, hunt * Epistaxis –dramatic –Long R – R intervals – Increased pulmonary pressure and then develop EIPH * Weakness/syncope * Myopathy * Colic –Electrolyte derangements * CHF * Cattle - primary GI disease (also foot rot and pneumonia). See anorexia and dec milk production –RDA

Answer 6

•Paroxysmal – lasts less than 24-48 hrs and spontaneously convert –Sometimes associated with K+ depletion (Furosemide- used in ROW prior to racing) and administration of bicarbonate. May be able to control with diet –Can get with exercise or competition – hard to diagnose as everytime you see them they are normal •Sustained

Answer 7

•Irregularly irregular rhythm –Becomes less irregular with chronicity •HR and pulse quality varies in intensity –Booming S1 on auscultation –Normally have an audible S3 –NO S4- active atrial contraction •Helps distinguish from other dysrhythmias –Usually normal or decreased HR; occ increased and will be increased if associated HF •Abnormally high heart rates at exercise – to counteract the CO (idioventicular responses) –Can be associated with VPD’s at exercise –Should perform exercising ECG’s on these animals; to understand if safe for riding

Answer 8

* Auscultation and physical examination * Resting ECG –No p wave –Normal qrs complex and t waves –f (fibrillation) waves – wobbling baseling •Further diagnostics PRIOR to attempting treatment (don’t need to treat them all): –Assessment of electrolytes and acid-base abnormalities –Echocardiography to assess for underlying cause/chamber enlargement –Exercising ECG

Answer 9

Atrial fib Normal QRST Instead of P with QRS Have F waves along baseline Variable R - R

Answer 10

1. Nothing 2. Quinidine sulphate (Quinidine gluconate 3. DC Cardioversion (equiv of paddles on ER)

Answer 11

–Negative inotrope –Many untoward side effects * Fatal dysrhythmias * Colitis – drug very irritant to mucosa and ulcers * Laminitis (not too common) /nasal oedema (nearly all get this)/ataxia –Use with caution – WARN owner and get signed consent * Need repeated physical examinations * Auscultation * Continuous ECG monitoring (at time and for 24hrs after) –First signs of toxicity – wide QRS -Check acid-base and electrolytes prior to treatment

Answer 12

–2 Wires into heart of anaesthetised horse via jugular vein – one just in RA, other through ride side and into PA. Shock the heart – want to restart this route –Positioned using ultrasound and radiography –Increased current to try and stop heart and convert to sinus rhythm

Answer 13

Shock on QRS (DO NOT SHOCK ON T = VENTRICULAR FIBRILLATION)

Answer 14

* Paroxsymal – excellent to good – unless keeps recurring * Sustained, no underlying cardiac disease (e.g. valvular). Cardioconver 80% –\< 3months – good either technique –\>3 months – better with DC conversion –Risk of re-fibrillation – risk factors there •Sustained, underlying cardiac disease (mitral and tricuspid regurgitation) –Average with DC conversion –More likely to re-fibrillate than category above •Sustained, heart failure – DO NOT CARDIOCONVERT –Poor to grave

Answer 15

* APD’s * VPD’s * VT * Third degree AV block Note: •RHYTHMS NOT COMPATIBLE WITH LIFE –Asystole –VF – unusual in horses

Answer 16

•MITRAL REGURGITATION and irregular rhythm Not regular No P for every QRS Atrial fib W and B – funky T wave = ventricular ectopic (may or may not be a problem – depend on exercise ECG) Needs cardiovert

Answer 17

False colic No P for every QRS W + B Largely the same Monomoprhic TC Treated with MG – didn’t do mch Given lidocaine and decreased (given by infusion) Developed VT and then died Had huge fibrosis through septum

Answer 18

Artefacts - skin twitch from clips Underlying AF

Answer 19

W + B RT complexes Ventricular premature depolarisation Risk turning VT then VF Then dropped dead in a field