Electrocardiography Flashcards Preview

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Flashcards in Electrocardiography Deck (20)
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1
Q

What is the point of electrocardiopathy?

A
  • Measures electrical activity of the heart
  • Heart rate
  • Conduction disturbances
    • Chamber enlargement
    • Electrolyte disturbances
    • Myocardial ischemia
2
Q

Normal conduction through the heart?

A
  • Sino-atrial node
  • AV node
  • Bundle of His
  • L and R bundle branches
  • Purkinje fibers
  • Rate depends on tone–SNS and PNS
3
Q

Normal EKG–what are the dif. waves?

A
4
Q

Which lead is the best regarding arrhythmias on an EKG?

A

Lead II

5
Q

What is the basic unit on EKG paper?

What does 1 cm equal? 1mm?

What dimensions are the tiny boxes? The big ones?

A
  • Basic unit = 1mm
  • 1 cm = 1 mV
  • 1 mm = 0.1 mv
  • Tiny box = 1x1mm
  • Big box = 5x5 mm
6
Q

What artifact is this?

A

60 Hz interference

7
Q

What artifact is this?

A

Shivering

8
Q

What artifact is this?

A

Purring

9
Q

How do you determine HR from an EKG?

A
  1. Determine speed (provided)
  2. # of PQRST’s in ENTIRE strip
  3. ^ convert to PQRST’s in 1 minute
10
Q

How do you find the mean electrical axis? Is it useful?

A
  • Average direction of activation of ventricular myocardium during systole
  • No–often inacurrate and can just use ultrasound instead
11
Q

How do you assess atrial size?

A
  • P pulmonade (peak)
    • Too tall = right atrial enlargement
  • P mitrale (mound)
    • Too wide = left atrial enlargement
12
Q

How do you assess ventricular size?

A
  • QRS complex–septal and ventricular depolarization
  • First neg. inflection = Q wave–don’t always get it, not unusual
  • R wave too high = left ventricular enlargement
  • Very deep S wave = right ventricular hypertrophy
13
Q

What is the most common EKG abnormality in cats?

A

Hypertrophic cardiomyopathy

14
Q

What is the most common cause of right atrial and right ventricular enlargement in dogs?

A

HEARTWORMS

15
Q

Right bundle branch block

A
  • Deep S
  • QRS prolonged
  • R decreased
  • Impulses come down –> jump from one cell to another via tight junctions–very slow –> QRS complex gets wider b/c process takes longer
16
Q

Left bundle branch block

A
  • Wide QRS
  • Normal height
  • Infections, trauma
  • Normal CO
  • Blocks/VPDs
  • Left atrium activated more slowly–look at septum via US
17
Q

Low voltage complexes

A
  • <1 to 1.5 mV
  • Obesity, pleural or pericardial effusion (picture), pneumothorax
  • Hypothyroidism, or diffuse myocardial disease
18
Q

What does it mean if there’s depression of the whole S-T segment?

A

Entire heart is deprived of oxygen = PROBLEM

19
Q

How is the Q-T segment related to heart rate? What can it change with?

A
  • Inversely proportional to heart rate
  • Changes w/ K, Ca, drugs
20
Q

How tall is the T wave supposed to be?

A
  • < 1/4 of the R wave (cats can be 1/3)
  • No rules as to whether it should be +/-, but should be consistent
  • If increased in amplitude (height) = hyperkalemia
    • Often due to hypertrophic cardiomyopathy