Basics of EKG part I Flashcards
each small square on ECG paper = how many seconds in duration and what amplitude
- 0.04 sec
- 0.1 mV = 1mm
five small squares or one large box = what duration
- 0.2 seconds in duration
What causes P wave
- produced by
- initiation of impulse in SA node
- depolarization of RA and LA
- impulse passing through AV junction
duration of P wave should be
0.06-0.10 seconds
PR interval consists of what segments? normal time for PR interval is
- start of P wave and ends at start of QRS complex
- 0.12-0.20
PR segment consists of what segments?
- isoelectric line between end of P wave and start of QRS complex
differentiate between Q, R, and S waves in terms of deflection
- Q wave: first negative deflection following PR segment
- R wave: first positive deflection following Q wave
- S wave: first negative deflection following R wave
normal QRS duration is
0.06-0.11 seconds
ST segment consists of what on ECG
- flat line that follows QRS complex
Where is the J point
where the QRS complex meets the ST segment
QT internval consists of what on ECG
- distance from onset of QRS complex until the end of T wave
QT internval is a measure of
- time of ventricular depolarization and repolarization
normal duration of QT internval
- 0.36-0.44 seconds
aVR augmented lead points in direction of and views what aspect of the heart
- Right arm positive
- views base of heart: atria and great vessels
aVL augmented lead points in direction of and views what aspect of the heart
- Left arm positive
- views lateral wall of left ventricle
aVF augmented lead points in direction of and views what aspect of the heart
- Left leg positive
- views inferior wall of inferior left ventricle
are the precordial (chest) leads positive or negative
all positive
List the placement of V1, V2, V3, V4, V5, and V6 on chest
- V1: 4th ICS on the right of sternum
- V2: 4th ICS on the left of sternum
- V3: halfway between V2 and V4
- V4: 5th ICS in mid clavicular line
- V5: anterior axillary line, same horizontal plane as V4
- V6: midaxillary line, same horizontal plane as V4
What are the modified chest leads
- MCL 1 and MCL 6
- provide continuous cardiac monitoring
- used in ER, telemetry, and ICU
- place positive electrode in same position as V1 or V6
List the leads that assess the anterior portion of the heart
- V1-V4
List the leads that assess the lateral portion of the heart
- I
- aVL
- V5-V6
List the leads that assess the inferior portion of the heart
- II
- III
- aVF
How can you calculate the heart rate using a 6 second interval ECG
- multiply by 10 the number of QRS complexes found in a 6 second portion of ECG tracing
What is the method of determining rate of ECG in which you find an R wave located on or near a bold and then find the next consecutive R wave. Bold line the 2nd R wave falls on represents heart rate
- 300, 150, 100, 75, 60, 50 method
When using 300, 150, 100, 75, 60, 50 method, what do you do if second R wave does not fall on a bold line (quick and dirty method)
- heart rate is approximated
- ex: falls between 75 and 60 BPM bold lines, then HR lies in between those BPM
When using the 300, 150, 100, 75, 60, 50 method, what is the acceptable way to determine rate when the R-R interval falls between large boxes
- ex: if rate is between 100-75, there are 25 numbers in between them, so each small box can represent a heart rate of 5 (25/5 small boxes)
- ex: if rate is between 75-60, there are 15 numbers between them, so each small box can represent a heart rate of 3 (15/5)
can the 300, 150, 100, 75, 60, 50 method be used with irregular rhythms?
NO
can the 1500 method to determine rate on ECG be used with irregular rhythms
NO
What is the 1500 method
- count the number of small squares between two consecutive R waves and divide 1500 by that number
- ** most accurate
normal HR lies between
- 60-100 bom
- < 60 bpm -> bradycardia
- > 100 bpm -> tachycardia
how can you determine if rhythm is regular or irregular? What are the methods?
- if the distance of R-R intervals and P-P intervals is the same -> regular
- methods
- caliper method
- paper and pen method
- counting the small squares method
What is the Caliper method to determine heart rate regularity
- position one point of caliper on a starting point
- open caliper until the point is positioned on the next R wave or P wave
- rotate caliper across to peak of the next consecutive (3rd) P wave or R wave
What is a wandering atrial pacemaker? what affect does it have on rhythm
- pacemaker changes location from site to site producing a slighly irregular rhythm
What is paroxysmal tachycardia
- a normal heart rate that suddently accelerates to a rapid rate producing an irregularity in the rhythm
what is patterned irregularity
- irregularity that repeats itself in a cyclic fashion
What is a irregularly irregular rhythm? this is seen in what condition
- no pattern to irregularity
- typically seen in atrial fibrillation
