Small Ani. Med 2- Cardio 10

pbhati17's version from 2018-03-01 18:44

Interpreting ECG’s in Small Animals

Question Answer
what is the electrical anatomy of the heart like?have the SA and AV nodes, and bundle branches: L anterior and posterior, and R bundle
what are the two main troubleshooting you should keep in mind with the ECG wires?not enough lube/alcohol or electrical interference
*which side are you supposed to lay the dog on when you hook up the ECG wires? R lat recumb
normal ecg parts
**leads: LEAD ONE (I) is moving from...Negative to positive, so, R to L
**leads: LEAD TWO is (II) is moving from...neg to pos, R to feet
**leads: LEAD THREE (III) is moving from...neg to pos, L to feet
what is aVR? where is it on the mean electrical axis? Lead aVR is pos where the right arm is. Moving to L arm and leg is neg
what is aVL? where is it on the mean electrical axis? Lead aVL is pos where the L arm is. Moving to R arm and leg is neg
what is aVF? where is it on the mean electrical axis? Lead aVF is pos where the L foot/leg is. Moving to L and R arm is neg
you need to draw the Mean elec axis and know what it means
the 6 leads of the mean elec axis are...I, II, III, aVR, aVL, aVF. They are labeled where they are positive
look at the degree labels on the mean elec axis and explain what is going on, explain the colors too.The degrees start being labeled at I with 0*, and move around to 180...then the top is labeled in NEGATIVES but this is only referring to degrees on the circle and the neg doesn't mean it's neg charge there-- for instance, aVR is POSITIVE at -150*. The Green area is where the normal electrical axis of the heart should be pointing. So if there is L vent enlargement, the MEA will start pointing more toward the 30*/0*
what are the 5 special questions, in order, of what you should think of when you are looking at an ECG(1) rate (2) rhythm (3) is there a P for every QRS and a QRS for every P (4) P/QRS morphology (5) Measurements (the intervals and such)
explain the setup of the graph paper the ECG is ran on (size/mm), and how it relates to power (mv) of the signalThere are the big and small boxes. HORIZONTAL: Each small box is 1mm and is representative of 0.1mv. Which means each big box is 5mm and work 0.5mv. VERTICLE: still small box=1mm and big box=5mm. AT 50mm/sec, vert lines are 0.02sec apart meaning 1 large box is 0.1 sec with 50mm/sec paper
the 25mm/sec paper is considered what kinda paper?this is the rhythem paper... the complexes are closer together, but Lots more complexes on paper to check rhythm and morphology. just remember to do measurements on 50 mm/sec paper!
which paper do you measurements on?50mm/sec paper
at 50mm/sec paper, how many boxes is one sec10 large boxes (bc each big box is 5mm)
How do you measure rate? (for 50 and 25mm/sec paper)take a bic pen with cap on it, lay it on paper-- that is 30 boxes (or count 30 boxes if you really hate yourself). Then count the number of complexes which occur in those 30 boxes. Then if it is 50mm/sec paper, mult your number of complexes by ***20. and if it is 25mm/sec paper, mult your number of complexes by ****10
SO if you dont have a Bic pen, she explains how to figure out rate on rhythm paper. tho i dont think she cares too much, read up through this shit(1) you can count the small boxes between 2 R waves, and then take that number and if it is 50mm/sec paper, do 3000/#. If the paper is 25mm/sec, it's 1500/#. (2) If you count the large squares between the R waves, it's 600/# at 50mm/sec paper and 300/# at 25mm/sec paper
ten big boxes is who much time passed on 50mm/sec paper?1 second
examples of things that can cause TACHYCARDIA arrhythmia?Sinus, Pain, Fear, Excitement, Fever, Anemia, Shock-early, Hyperthyroidism, Cardiac Disease, Supraventricular or Ventricular
examples of things that can cause BRADYCARDIA arrythmia?Sinus ,Shock-late, Hypothermia, Hyperkalemia, Hypoglycemia, Pharmaceuticals, Parasympathetic tone (GI, Resp, Neuro Dz), AV Blocks
what makes something a normal sinus rhythm (NSR)?has p, QRS, T , they looked alike and looked normal
what is a phasic sinus arrhythmia?associated with respiration, Increase with inspiration and decreases with expiration
what nerve can be associated with sinus arrhythmias?vagal tone must be considered


Question Answer
* if P increased in amp or duration, what should you think caused this?R or L atrial enlargement
* if R has increased amplitude, what do you think is causing this?Left Vent enlargement (taller bc took more power to zap through thick muscle)
* if R has inc duration, do what you think is causing this?Left Bundle branch block (taking longer to get around and through)
* if S has inc amplitude (is very deep), what do you think is causing this?right vent enlargement
on ecg, P, R, and S are generally associated with which anatomical strutures?P= both atria. R= L ventricle. S= R ventricle
* if S has inc duration, what do you think is causing this?right bundle branch block
measurements: what is the important number to keep in mind, if P is > ___0.04
measurements: what is the important number to keep in mind, if P-R is > ___0.12
measurements: what is the important number to keep in mind, if QRS is > ___0.06
*(will need to know how to do this) Isoelectric lead estimate: how do you do this?find isoelectric lead, which means upward deflection and downwards deflection should be about even (means this is the lead where electrical forces directed perpendicular to lead), then find opposite lead on axis chart-- is it positive or negative deflection on ecg? go positive or negative on axis chart
so, is this dogs heart normal? look for isoelec lead. so it is aVL is most isoelec. Go to mean electrical axis and find the lead perpendicular to aVL-- it is lead II. look back to ecg chart-- is lead II a pos or neg inflection? positive- go back to MEA- where is lead II postitive? at 60*. This is in the green range, which means it is NORMAL
is this dog's heart normal? isoelec lead= III. perpendicual to that on the mean elec axis chart is aVR, look at avr on ecg chart-- AVR had a NEG inflection on there, so look back to MEA, avr is negative at 30* on the chart-- this is abnormal (not in green area) ((bonus: since it is moving up that side of the MEA, you know it's bc of L vent enlargement bc moves into L side but abnormal)
what are some reasons you might see a Low amplitude on the ECG?Pleural effusion, Pericardial effusion, Obesity, Hypothyroidism, Pneumothorax, Diffuse myocardial disease, Normal variation
Figure this outRATE: between the **'s is 30 boxes, 9 complexes between the **, and 50mm/sec paper means 9x20= 180. This is a tachycardia. RHYTHM: irregularly irregular. P/QRS QRS/P: There is a P for every QRS...there is not a QRS for every P (too many P's!). P/QRS MORPHOLOGY: the QRS's look pretty normal but the P's are abnormal. MEASUREMENTS: look at chart. and how many mm/sec (50) .... normal is <0.06(one large box is 0.1 sec in large box in 50 mm/sec paper)... so are QRSs wider than those big boxes? (distance between vertical lines) They dont measure big. but pushin it. So from this we have concluded that it's a atrial problem... irreg irreg, tachycardia... it's a supravent tachycardia (can label is atrial fib bc ps all crazy and dont look like each other= fibrillation) so atrial fibrillation