ECG Flashcards
electrocardiograph produces electrocardiogram true/false
true
where is lead I between
right arm - left arm
where is lead II between
right arm - left leg
where is lead III between
left arm - left leg
what is the positioning for the precordial leads
V1 - 4th intercostal space on right parasternal line
V2 - 4th intercostal space on left parasternal line
V3 - between V2 and V4
V4 - 5th intercostal space midclavicular line
V5 - follows horizontal line - ant axillary
V6 - follows horizontal line - midaxillary
positive wave indicates
moving towards the electrode
what does the P wave represent and how long does it normally last
atrial depolarisation
0.08-0.1 seconds
what does the PR interval represent and how long does it normally last
AV nodal delay
0.12-0.2 seconds
what does the QRS complex represent and how long does it normally last
ventricular depolarisation
0.12 seconds
what does the T wave represent
ventricular repolarisation
how do you calculate a regular heart rate
300/(number of large squares in R-R interval)
how do you calculate an irregular heart rate
300/(number of QRS peaks in 6 boxes)
right axis deviation would show
Lead I negative
Lead III positive
left axis deviation would show
Lead I positive
Lead III negative
right axis deviation is a sign of
right ventricular hypertrophy
left axis deviation is a sign of
conduction defects
the absence of P waves is likely due to
atrial fibrillation
atrial flutter
what is the ECG characteristic of atrial flutter
saw tooth ECG
prolonged PR interval is a sign of
AV node block
shortened PR interval arises because
the conduction originates somewhere closer to the AV node - eg accessory pathway
shortened PR interval causes what condition
Wolf Parkinsons White syndrome
Delta waves are due to
shortened PR interval, slurred QRS upstroke and classical sign of WPW syndrome
QRS complex of <0.12 secs likely to be
supraventricular tachycardia
QRS complex of >0.12 secs likely to be
ventricular tachycardia
are Q waves always pathological
no
what are pathological Q waves a sign of
previous MI
to diagnose a STEMI ST elevation must be present
> 1mm in 2 or more contiguous leads
>2mm in 2 or more precordial leads
ST depression is a sign of
myocardial ischaemia
tall T waves are a sign of
hyperkalaemia
when describing an ECG what must be covered
patient name and DoB date and time the ECG was recorded calibration electrical activity present calculate HR and see if rhythm is regular cardiac axis P waves present, describe, followed by QRS ST abnormalities
how many seconds is a big box on ECG paper
0.2 seconds
