General Eval of Equine CV System

Lectures 16 and 17

What should be included in a history when talking to the owner for suspected CV issues?

signalment (breed disposition)

clinical signs (peripheral edema, jugular pulsations, harder time breathing)

effect on performance (is it decreased?)

use of horse

preventative care

issues (thrombophlebitis, past and current issues, trauma)

What can be used for a cardiovascular examination?

physical exam

cardiac and pulmonary auscultation

ECG / Stress ECG

Echocardiogrpahy / Stress echo

Hematology and blood chemistry / cardiac enzymes

Blood gas, Blood culture

aterial blood pressure

pulmonary radiographs

other tests

What should you be evaluating during a physical exam for suspect CV issues?

temperature of extremities

mucus membranes

arterial pulse quality

jugular vein

peripheral edema presence

evaluation of respiratory system / presence of pulmonary edema

BCS

What are three reasons why we palpate the pulse?

quality of pulse (strong v weak) / digital pulses could indicate inflammation in foot

heart rate

rhythm

What are we evaluating when evaluating the jugular vein on PE?

inspection, palpation for thrombophlebitis, firmness, etc

pulsation —> reflects pressure in atria and can give insight to rhythm

jugular filling

What are potential causes for peripheral edema?

hypoproteinemia unrelated to cardiac disease

right heart insifficiency

Where are common areas to find peripheral edema?

pectoral region

legs

abdomen

prepuce

Which sided heart insufficiency is associated with pulmonary edema?

left

Which sided heart failure matches the following:

• congestion of peripheral tissues (peripheral edema)

• liver congestion

• GI tract congestion (anorexia, weight loss)

right sided

Which sided heart failure matches the following:

• decreased cardiac output (exercise intolerance)

• pulmonary congestion

• impaired gas exchange (hypoxia)

• pulmonary edema

left sided

Why is BCS important for CV evaluations?

cardiac cachexia can result from severe cardiac disease

growth deficits can result from cardiac ventricular malformation

What should we be evaluating during cardiac auscultation?

precordial thrill (vibration indicative of grade 5+ murmur)

heart rate

normal heart sounds

murmurs

rhythm

Heart rate typically rises _____ to exercise effort and plateus at maximum effort.

porportionally

What is a normal HR at a walk?

50-100

What is a normal HR at a trot?

70-120

What is a normal HR at a gallop?

140-240

What is a normal HR at rest?

28-48

When should you assess the heart rate in regards to exericse?

at rest and during exercise (or immediately after exercise)

What sound is AV valve closure (mitral and tricuspid)?

S1

What sound is semilunar valve closure (aortic and pulmonary)?

S2

What sound is early diastolic ventricular filling?

S3

What sound is atrial contraction (atrial systole)?

S4

S1 to S2 is?

systole

S2 to S1 is?

diastole

When do S3 and S4 sounds occur?

in between S2 and S1 (diastole)

Which phase is described:

• aortic and pulmonary valves open

• mitral and tricuspid valves closed

• contraction + ejection from ventricle to aorta and ventricle to pulmonary artery

• S1 to S2

systole

Which phase is described:

• mitral and tricuspid valves open

• aortic and pulmonary valves closed

• relaxation + filling from atria to ventricle

• S2 to S1

diastole

When listening for murmurs, what are you trying to identify?

timing of murmur (systole, diastole, continuous?)

duration of murmur (beginning, en, middle, holo, pan?)

Point of maximal intensity (aortic, pulmonary, mitral, tricuspid?)

Character (crescendo, decrescendo, musical, other?)

Intensity

Which grade of murmur is described:

• very faint

• localized at point of maximal intensity

• hardly audible

Grade 1

Which grade of murmur is described:

• weak

• easily heard at point of maximal intensity

Grade 2

Which grade of murmur is described:

• moderate

• easily heard

• irradiation

Grade 3

Which grade of murmur is described:

• intense

• large zone of irradiation

Grade 4

Which grade of murmur is described:

• intense

• large irradiation

• precordial thrill

Grade 5

Which grade of murmur is described:

• intense

• precordial thrill

• heard without stethoscope

Grade 6

Regurgitation occurs at the valve that should be?

closed

Systolic regurgitation murmurs affect which valves? Include which side of the horse they are on.

mitral (left)

tricuspid (right)

Diastolic regurgitation murmurs affect which valves? Include which side of the horse they are on.

aortic (left, frequent)

pulmonary (left, RARE)

A murmur audible between S1 and S2 on the left is most likely coming from which valve?

mitral

A murmur audible between S1 and S2 on the right is most likely coming from which valve?

tricuspid

A murmur audible between S2 and S1 on the left is most likely coming from which valve?

aortic

List examples of regular rhythms.

sinus rhythm

sinus tachycardia

sinus bradycardia

List examples of regularly irregular rhythms.

AV 2nd degree block

List examples of irregularly irregular (chaotic) rhythms.

atrial fibrillation

List indications for echocardiography.

cardiac mumur (most frequent)

dysrhythmia

congenital defect (ventricular septal defect)

poor performance

decreased cardiac sounds

fever of unknown origin

collapse, weakness

signs of cardiac insufficiency

severe respiratory problem

What can be seen in this echocardiogram at rest?

ventricular septal defect

Which type of echocardiogram uses lines transmitted in an arc to assess shape, size, motion, and abnoramlities?

2D

Which type of echocardiogram uses time-motion with a single line of ultrasound to assess chamber size and thickness?

M-mode

What can be determined using M-mode echocardiogram?

chamber size and thickness

fractional shortening

What are the different types of doppler echocardiography?

color doppler

pulse wave doppler

continuous wave doppler

What can we see with a doppler echocardiogram?

velocity, direction, and character of blood flow

List utility for echocardiography.

visualization and measurement

assessment of performance

localization and assessment of flow disturbances

List limitations of echocardiography.

? consequences of cardiac dysfunction

! need physical examination

List indications for ECG.

poor performance

arrhythmia on auscultation

valvular insufficiency

myocardial disease

assess heart rate, rhythm, conduction time

Horses with aortic regurgitation are more prone to what?

arrhythmias

What is the pacemaker and conductor of the heart?

SA node

What direction do impulses flow in the heart?

SA node —> atria —> AV node —> ventricles

What is the gatekeeper of the heart acting as a protective mechanism to regulate impulses going to the ventricles?

AV node

What part of the heart is responsible for spreading the impulses that lead to the contraction of ventricles?

bundle brunches, Purkinje fibers

What is a physiological arrhythmia in horses and athletes that is considered physiologcal and that goes away with exercise?

second degree AV block

What equipment is needed for an ECG?

leads

electrodes (improve contact)

speed 25mm/s

amplitude 1cm/mV

What are the three types of ECG?

standard

holter and telemetry

exercise

What happens to the waves during an exercise ECG due to the change in lead placement?

the QRS complexes appear upside down

List the steps to analyze an electrocardiogram.

assess overall quality of recording

identify paper speed and calculate heart rate

assess if rhythm is regular or irregular

identify most normal P-QRS-T complexes if present and compare them to abnormal

measure the PR, WRS, and QT intervals

define the rhythm

seek second opinion if needed

What is an example of a pathologic arrhythmia — meaning an arrhythmia that will likely have consequences for the horse?

atrial fibrillation

What do we evaluate when an arrhythmia is present?

rate (fast or slow)

origin and conduction (supraventricular or ventricular)

timing (premature or escape)

frequency (intermittent or persistent)

cause (physiological or pathological)

What lab analysis tests can be used for CV cases?

CBC, fibrinogen

biochemistry

blood gas

blood culture

urinary output and urine analysis

cardiac enzymes and proteins

vitamin E and selenium concentration

toxicology screening

viral titers

What cardiac enzymes and proteins can be used?

Iso-CK (CK-MB)

Iso-LDH (LDHI)

Troponins —> use in myocardial disease cases —> very expensive, not as good as in humans

What view of echocardiogram is this?

right parasternal view (longitudinal)

What view of echocardiogram is this?

left parasternal view (longitudinal)

What view of echocardiogram is this?

short axis view (cross section)

What quality/pitch does this symbol indicate?

crescendo

What quality/pitch does this symbol indicate?

decrescendo

What quality/pitch does this symbol indicate?

crescendo-decrescendo

What quality/pitch does this symbol indicate?

plateau