Lecture 2: ECG Flashcards
(27 cards)
In which body position do you perform an ECG?
Right lateral
Lead I is between:
RF and LF
Lead II is between:
RF and LH
Lead III is between?
LF and LH
What angle is lead I?
0
What angle is lead II?
60
What angle is lead III?
120
Which specialised conduction fibres are in the atria?
None
What determines if a wave is +ve or -ve?
Whether it is moving towards or away from the +ve electrode
What can the wave look like if it is perpendicular to the +ve electrode?
Biphasic
What can you NOT diagnose from an ECG?
Heart failure
In which species can and ECG indicate chamber enlargement?
Dogs and cats
Which five other abnormalities can be diagnosed with an ECG?
Electrolyte abnormalities, myocardial ischaemia/hypoxia, drug intoxication (esp digoxin), pleural/pericardial effusion, hypothyroidism
What are 5 causes of a QRS arising without a P?
Ventricular depolarisation, junctional depolarisation, atrial standstill, atrial fibrillation, sinus arrest with escape complexes
Which node controls a sinus rhythm?
SA
What are three characteristics of a sinus rhytm?
P for every QRS, PR interval constant, P wave is positive in lead II
In which species in sinus arrhythmia normal?
Dogs
What causes sinus arrhythmia?
Vagal tone
Why is sinus arrhythmia abolished under anaesthetic?
Adrenergic tone and haemodynamic changes
How do you calculate an instantaneous heart rate?
R-R interval
What is an example of a situation where you may need to calculate multiple heart rates?
Multiple rhythms, e.g. A-V block (separate atrial and ventricular rhythms)
Why are T waves very variable?
Show repolarisation of an abnormal depolarisation
What is MEA usually in the dog?
Towards lead II (aVF)
What is MEA like in cats?
Much more variable
