ECG Wave Forms Flashcards
An inverted P wave/ biphasic P wave may indicate ?
An ectopic rhythm or ischemia.
An unusually tall P wave may be a sign of what ?
Atrial enlargement
An unusually wide QRS Complex >120 Ms maybe a sign of ?
BBB or ventricular hypertrophy
Depression of the PR segment is seen in ?
Pericarditis
PR interval = ?
P wave + PR segment
QRS interval=
The duration of the QRS Complex
The duration of the normal QRS Complex?
80 to 100 Ms. When it is between 100 to 120ms, the QRS duration is slightly prolonged.
A QRS duration> 120 Ms indicates?
The cardiac impulse conducts through cardiac myocytes instead of Hiss- Purkinje system. It often occurs in BBB, non specific interventricular conduction delays and ventricular arrhythmias.
QT interval=
The duration of QRS Complex+ ST segment+ T wave
What is RR interval
It is the duration of all wave forms and segments in one cardiac cycle
What is the duration of normal PR interval?
120-200 Ms.
A PR interval < 120 Ms indicates?
An abnormal conduction between atria and ventricles
A PR interval>200 Ms indicates?
Delayed conduction through the AV node due to age related degeneration of the AV node or medications such a calcium channel blockers or beta blockers.
One small square of ECG =
40 Ms or 0.04 sec
One large square of ECG is equal to?
200 Ms or 0.20 seconds. / 5mm
An ECG rhythm strip recorded for 1 min will have how many large and small squares?
1500 small squares or 300 large squares
The large square method of ECG rate calculation (300/RR intervals in large square) is useful in ?
Regular rhythms at regular rates.
Small square method of ECG rate calculation is useful in ( 1500/RR interval in small squares)?
Useful for very fast regular rhythms.
R wave method of ECG rate calculation is useful in ( number of R waves X6)?
Useful for slow and irregular rhythms.
Normal HR in newborn?
110-150 beats
Normal HR in 2 years old?
85-125 bpm
Normal HR in 4 years old?
75-115BPM
Normal HR in 6 years old+ ?
60 to 100 BPM
What is the advantage of doubling the standard rate of ECG paper speed?
It can help to reveal subtle ECG findings hidden at the slower rates, in particular atrial flutter waves in a 2:1 block.
what are the 7 steps of ECG rhythm analysis?
1) Rate - Tachycardia or Bradycardia
2) pattern of QRS Complex - Regular or irregular. If irregular is it regularly irregular or irregularly irregular?
3) QRS morphology- Narrow vs wide
4) P wave - absent or present
5) Relationship between P wave and QRS Complex - AV association or dissociation
6) Onset and termination- abrupt or gradual
7) Response to vagal maneuvers.
What direction of current lead V1 and V2 measure?
Anterior forces as positive waves and posterior forces as negative waves.
Lead 1 and V6 measure what direction of force ?
Leftward forces
Normal P wave axis ?
0- 75 degree
What is the normal P wave duration?
<120 ms
What are the inferior leads ?
Lead 2, aVF, and 3 are called inferior leads because they observe the inferior wall of the left ventricle.
Lateral leads of ECG are ?
Lead 1, aVL, V5, and V6
Anterior leads of ECG are
V3 and V4
Septal leads of ECG are ?
V1 and V2
Einthoven’s Law ?
Lead 1 + Lead 3 = lead 2
ECG leads of septal wall supplied by LAD?
V1 and V2
ECG leads of anterolateral wall supplied by LAD?
V5 and V6
ECG leads of anterolateral wall supplied by LCX ?
V4 and V5
ECG leads of anterior wall supplied by LAD?
V3 and V4
ECG leads of lateral wall supplied by LCX?
Lead 1, aVL, -aVR
ECG leads of inferior wall supplied by RCA?
Lead 2,3,aVF
Duration of QT interval?
400 to 440 Ms in men and 400 to 460 Ms in women
