Pack Flashcards
How many small squares are in each large square in an ECG paper? What is the width and height of the large square
No. 5x5
Width and height:5mm x 5mm
What does the Y axis of each large square represent?
Voltage
(bc V looks like a Y without a stick)
How many milivolts is the Y axis of each large square?
0.5 mv
(so each small square it 0.1)
How many seconds is the x axis of each large square?
0.20
What does the X axis of each large square represent?
duration
How many seconds is the x axis of each small square?
0.04 s
(bc the large square is 0.20 and there are 5 small squares, so 0.20/5= 0.04)
How many milivolts is the Y axis of each small square?
**0.1 mv **
(bc the large square is 0.5, and we have 5 small squares, so 0.5/5= 0.1)
How do you measure the exact time interval of each heart beat?
You count the number of small boxes (or no. of big boxes x 5) between 2 R-R intervals, then you multiply it by 0.04.
How do you do an Exact calculation of Heart Rate from an ECG trace?
You calculate the R-R interval (the time of each heart beat)
then you divide 60 by it.
So if the R-R interval is 0.8, then the heart rate would be= 60/0.8 = 75 BPM
How do estimate the heart rate from ecg?
300/by number of big boxes in the R-R interval
How do you calculate the time of segments and intervals from the ecg?
1.Count the number of small boxes inside the interval
- Multiply No. of boxes x 0.04
What is the PQ/PR interval rate supposed to be?
0.12-0.2 seconds
What is the QRS complex time supposed to be?
< 0.10 seconds
What is the QT interval time supposed to be?
generally less than 0.4 s at rest
What does the mean electrical axis indicate?
Indicates:
– Orientation of heart –
Size of ventricular chambers
– Conduction block
What is the normal mean electrical axis?
From +90 till -30
What is the range for the Left axis deviation of the MEA? What are the conditions that this is commonly seen in?
Range: -30 to -90
Conditions: Commonly seen in any condition causing
left ventricular hypertrophy, inferior STEMI
What is the range for the Right axis deviation of the MEA? What are the conditions that this is commonly seen in?
Range: +90 to +180
Conditions: Normal finding in children and tall thin adults
Commonly seen in any condition causing
right ventricular hypertrophy
What is the range for the Exterme axis deviation of the MEA? What are the conditions that this is commonly seen in?
Range: +180 to -90
Conditions Lateral STEMI, COPD, Dextrocardia
How do you know if it is normal axis in ECG?
How do you know if it is Left axis in ECG?
How do you know if it is Right axis in ECG?
If lead I is negative, look at avF
How do you know if it is Extreme axis in ECG?
How many small squares would a normal pq interval be?
< 5
What does it mean if the p wave is upside down?
The SA node is non functional, The av node is acting as the main pacemaker. (upside down bc the ap is spreading away from the +ve electrode)
What is normal duration of QRS complex? How do you determine it?
Normal: <0.1
Determine: Look at the number of small boxes that the QRS covers. (normal in this case bc 1 box so 0.1 sec)
What is sinus bradycardia?
When everything is normal except the BPM is low (less than 60)
(brad, so broad, so the spaces between the R waves will be broad)
What is sinus tachycardia?
When everything is normal except the BPM is High (more than 100)
What is the first degree heart block? How do you determine that it is a first degree heart block from the ECG? What are some conditions that cause it?
It is a partial block of the av node which prolonges The PQ interval.
Diagnosis: if the PQ interval is prologned (more than 0.20 s) and there is normal rythem P-QRS-T
Conditions: fibrosis,
Calcium channel blocking drugs
enhanced vagal tone
athletic training.
What is a second degree heart block?
Pr interval is over 0.24 seconds, and the pre interval keeps on getting longer and longer after each contraction, until no QRS is generated.
What are the two types of Second degree heart block?
Mobitz Type I
Mobitz Type II
What is Second degree heart block Mobitz Type I? How do diagnose it from the ECG? What are some conditions that this can be seen in?
It is: Partial block of the av node
Diagnosis:Progressive lengthening of the PR interval until not QRS is generated
conditions: may be seen normally in children, athletes or individuals with elevated vagal tone.
What is Second degree heart block Mobitz Type II? How do diagnose it from the ECG? What are some conditions that this can be seen in?
It is: Partial block of the Bundle of his (bc type II so two branches)
Diagnosis: Sudden loss of QRS, wide QRS (more than 1 small square)
conditions: may be seen normally in children, athletes or individuals with elevated vagal tone.
What is the general treatment for Second degree mobitz type II?
Pacemaker implantation is generally the treatment for this condition
What is Third degree heart block?
- Complete block of AV node or Bundle of His
What is Third degree heart block? How do diagnose it from the ECG?
It is:Complete block of AV node or Bundle of His
Diagnosis: QRS is opposite to t waves, if QRS is positive, t waves will be negative and vice versa. P-P interval is Normal, R-R is short 20-40.
2-4 p waves for every QRS.
Where is the AP of the ventricles generated in Third degree heart block?
Purkinje-his system
What is atrial fibrillation? How do you diagnoss it on the ecg
Re-entry current causes a “jittery” reading on the ECG, no clear p waves, the r-waves are very inconsistent.
What is ventricular fibrillation? How do you diagnoss it on the ecg
it is Re-entry in ventricles
Diagnosis Distinguishable by the total absence of any pattern
What is Regularly regular Rhythm? What is an example?
The R-R intervals are the same for each heartbeat and the rhythm is maintained. (P-QRS-T is the same, even if smth is wrong with one of the parts)
(regular pattern and rhythm)
Example Sinus bradycardia, sinus tachycardia, first degree heart block
What is regulary irregular Rhythm? Example?
Rythm that doesn’t have the same R-R intervals, but has a pattern that repeats.
(P-QRS-T is not consistent, but its inconsistency is repeated )
Time: Second degree heart block
What is irregulary irregular Rhythm? Example?
No pattern, no rhythm
example atrial fibrilation
What is prolonged QT syndrome?
Prolonged QT interval due to genetic mutations.
What is the normal duration for QT interval? What is considered as prolonged?
Normal: < 400
Prolonged > 450 ms in men and 470 in women
How do you measure the corrected QT interval using bazett’s formula?
