Ecg Flashcards
What are the normal variants in ECG ?(for further roller
in chapter 6 )
- T - waves inverted are normal in AVR and V 1 in any patient however twave is allowed to be inverted in lead III if it’s upright in lead VF
Sinus arrhythmia -ecg me pg31
What s the standard paper speed ? and how many seconds is 1 big block equivalent to ? how many seconds is 1 small block
equivalent to ?
25mm /s
1big block is 0.2 sec
1 small block is 0.04 sec
(oxford pg 96)
What should the
voltage calibration be
set to? and why?
1mv causes 1cm of upward deflection ( ecgME pg 23)
A limited amount of information is given by the height of the Pwaves, QRS complexes and T waves, provided the machine isproperly calibrated. A standard signal of 1 millivolt (mV) shouldmove the stylus vertically 1 cm (2 large squares) (Fig. 2.8), and this‘calibration’ signal should be included with every record.ecg me pg44
Is ST segment isoelectric? how many mm ot planar e tevations or depression implies infarction?(oxford Pg96)
Planar elevation > 1mm or depression > 0.5mm implies in farction or ischemia respectively
What does P wave represent ? QRS? Twave ?
P wave is atrial depolirization (possibly also contraction but please find out )
QRS is ventricular depolarization
T wave is ventricular repolarization
(please verify with source.)
how many seconds or blocks should each last ? P ? QR S ? PR interval etc.
P wave =
PR interval = 3-5 small blocks.(0,12sec-0.2sec) PR interval is very short, either the atria have beendepolarized from close to the AV node, or there is abnormally fastconduction from the atria to the ventricles. Ecg me pg43
QT interval. =/< 3 small block (0,12sec)The QT interval varies with the heart rate. It is prolonged in patientswith some electrolyte abnormalities, and, more important, it isprolonged by some drugs. A prolonged QT interval (greater thanapproximately 480 ms) may lead to ventricular tachycardia.
QRS complex duration isnormally 0.12secs ( 3 small squares) or less, but anyabnormality of conduction takes longer, and causes widened QRScomplexes. Remember that the QRS complex representsdepolarization, not contraction, of the ventricles – contraction isproceeding during the ECG’s ST segment.
ST segment
Oxford pg 96 )
when assessing an ECG what components should you look at?
Rate:
Rhythm
p-wave:
width
Q- wave:
st segment
Twave
oxford additional:
axis
QT interval (corrected QT interval )
J wave
other additionals
u-wave:
What are the following and
how can you identify them ?and what causes them
1. P mitrale
z P - pulmanale
3. Pseudo - pulmonale and it’s cause
4.absent P wave.
( according to oxford pg 96)
P- Pulmonale, peaked P wave’s which indicate right atrial hypertrophy
Pseudo pulmonale is caused by hyperkalaemia
P mitriale bifid p wave which indicates Left atrial hypertrophy
absent P wave= Af , P hidden due to junctional or ventricular rythym. -
What does a high amplitude QRS complex mean/ suggest?
how to correct QT interval and
what is the normal duratio.n? (oxford ‘
QT interval is dependent on the heart rate , normal is 480ms (0,48sec in oxford)
.corrected QT= QT / square root of RR interval
Define heart block?
If there is more than one P wave before each QRS complex, then conduction to the ventricles is abnormal. This is called heart block ( ECG ME Pg 26)
width of QRS greater then 3 small blocks suggest?
If so, this means there is abnormal conduction through the ventricles.If the QRS complex is wider than 3 small squares, the spread of electricalactivation through the ventricles must be slow. This could be becauseconduction through the ventricles is abnormal, or it could be because theelectrical impulse erroneously began in the ventricular tissue rather thancoming through the bundle of His (ecg me pg 27)
how can you estimate. If bradycaid a s tachycardice using the blocks. ?
> 6 big blocks between R-R interval suggests brady cardia of @ least < 50 bpm
<3 big blocks between RR interval suggests tachycardia 100pm. (Ecg made e pg 26)
Name types of rythym
Sinus rythym sinus arrythmia
Narrow complex tachycardia e,g
broad complex tachycardia .
Complete heart. Block
Extrasystoles( ectopic beats)
A fib
A flutter
Ventricular fibrillation
oxford ecg me pg 30
examples of types of rhythms and their relevant ECCG Changes
The word ‘rhythm’ is used torefer to the part of the heart which is controlling the activationsequence. The normal heart rhythm, with electrical beginning in the SA node, is called ‘sinus rhythm’. ECGMEPg39
What can make a u wave pathological? Ecg me pg40
In some ECGs an extra wave can be seen on the end of the T wave,and this is called a U wave. Its origin is uncertain, though it mayrepresent repolarization of the papillary muscles. If a U wave followsa normally shaped T wave, it can be assumed to be normal. If itfollows a flattened T wave, it may be pathological
ECG Red flags ecgme pg34
ECG red flags
The following ECG abnormalities could be clinically important, but always consider the patients’ clinical state first. Any of these changes could present as chest pain, breathlessness, palpitations or collapse.
• Ventricular rate above 120 bpm or below 45 bpm
• Atrial fibrillation
• Complete heart block
• ST segment elevation or depression
• Abnormal T wave inversion
• Wide QRS width
how many big sqaures in 1 minute and 1 second respectively (on ecg paper )?.
5 big squares=1 sec
300 big squares= 1 minute .
what is a J-wave? What does it indicate? oxford 96.
a notch@the point where S-wave ends and where ST segment begins seen in hypothermia hypercalemia and SAH
Which lead usually used to identify the cardiac rhythm and why?
The cardiac rhythm is identified from whichever lead shows the Pwave most clearly – usually lead II.
What is the difference between sinus arrest , junctional escape ,ventricular escape and svt?
