Flashcards in Chapter 5 Deck (65):
What is evaluated and classified when determining dysrhythmias?
The ECG waveform has various components—such as waves, segments, and intervals—that are evaluated and classified based on their size, length of time, and location on the tracing.
Normal Heart rate:
15-25 lil boxes P-P or R-R intervals
Name the five components that must be evaluated on a rhythm strip.
Rhythm (regularity): taking measure of P to P or R to R or S to S intervlas for at least 6 consecutive seconds
P wave configuration
QRS duration and configuration
A regular rhythm has 19 small boxes between the P-P interval. What is the heart rate?
After you measure the QRS duration and configuration, what other questions need to be answered?
Are all the QRS complexes of equal length?
What is the actual measurement, and is it within the normal limits?
Do all QRS complexes look alike, and are the unusual QRS complexes associated with an ectopic beat?
The most common monitoring lead
P wave represents
atrial depolarization (contraction)
QRS complex represents
The rhythm of atrial contraction is evaluated by assessing
the regularity or irregularity of the occurrence of the P waves
The QRS complexes are assessed to evaluate
Atrial is determined by the
P-P wave interval measurement.
The ventricular rate is determined by the
R-R wave interval measurement
If the atrial and ventricular rates are different, there is a problem with the
Determining the atrial rate of a regular rhythm tracing
Count the number of small boxes between the P-P intervals, divide into 1500
Determining the ventricular rat of a regular rhythm tracing
Count the number of small boxes between the QRS complexes, divide into 1500
Determining heart rate in an irregular rhythm tracing
6-second rule: Identify 6 seconds on strip (2 vertical lines at the bottom or top of strip), count the number of complete complexes seen in one 6 second interval, multiply the number of complexes by 10.
How to identify the P wave configuration (shape)
Are the shapes and waveforms all the same?
Does each P wave have a QRS complex following it?
What does the PR interval measure?
The time it takes the electrical current to be initiated at the sinoatrial node and travel through the electrical current pathway to cause a ventricular contraction
How to measure the PR interval
Measure form the beginning of the P wave to the beginning of the QRS complex
Normal range of the PR interval
0.12 to 0.20 seconds
What does the QRS complex determine
Duration of time it takes for the ventricles to depolarize or contract
Normal QRS complex duration
0.06 to 0.10 seconds
Hoe to measure the QRS complex duration
Measure between the beginning of the QRS complex and the J point
What does the J point indicate
The ventricular depolarization (contraction) completion and beginning of re-polarization
Primary pacemaker of the heart
SA (sinoatrial) node
Normal conduction pathway
SA node, AV node, bundle of His, bundle branches of the ventricles (contraction!!!)
Why is called sinus rhythm?
Because the rhythm starts at the SA node
The intervals between the two P and two R waves will occur in a consistent pattern
Both the atrial and ventricular rate twill be between 60 and 100 bpm
NSR P wave configuration
The P waves will have the same shape and are usually upright in deflection on the rhythm strip. A P wave will appear in front of every QRS complex
NSR PR interval
The PR interval measurement will be between 0.12 and 0.20 seconds, which is within normal limits. Each PR interval will be the same, without any variation
NSR QRS duration and configuration
The QRS duration and configuration measurement will be between 0.06 and 0.10 seconds, which is within normal limits, Each QRS duration and configuration will be without any variations from PQRST complex to complex
Observation guidelines used to assess the blood supply to the vital organs of the body to maintain normal function
Sx's of neurological low cardiac output
Change in mental status, light headedness, dizziness, confusion, loss of consciousness
Sx's of cardia low cardiac output
Chest pain, palpitation, chest discomfort, enlarged cardiac size, congestive heart failure
Sx's of respiratory low cardiac output
difficulty breathing. SOB, frothy sputum, fluid present in lungs, lung congestion
Sx's of urinary low cardiac output
Decreased urinary output of less than 30ml in one hours
Sx's of peripheral low cardiac output
Hypotension, pale skin, skin cool and clammy to the touch
What to include in the ECG tracing
pt's name, date, time, performer's initials
Where does sinus bradycardia originate from
S.Brady criteria for classification
The heart rate is less than 60 bpm, and all other measurement are WNL
Sx's and signs of S.Brady
The pt may or may not experience signs ans sx's of low cardiac output.
Tx of S.Brady
May require drug administration or application of a pacemaker
S.Tachy criteria for classification
The heart rate is greater than 100 bpm, and all other measurement are WNL
Cardiac output in S.Tachy
Sx's of S.Tachy
palpitations and other sx's of low cardiac output
Condition in which the heart rate remains within normal limits but is influenced by the respiratory cycle and variations of vagal tone causing the rhythm to be irregular
Condition in which impulses over the vagus nerve cause a decrease in heart rate
S.Dys criteria for classification
The P-P and R-R intervals will progressively widen then narrow, following the pt's breathing pattern and all other measurements are WNL
Sx's and signs of S.Dis
No clinical signs and sx's unless hr is less between 40-50 which will produce palpitation or dizziness
Sometimes referred to as sinus pause, occurs when the A node stops firing, causing a pause in electrical activity. During the pause no electrical impulse is initiated or sent to the normal conduction system to cause either an atrial or a ventricular contraction
When is sinus alert considered a medical emergency?
When it reaches or exceeds 6 seconds. Code Blue procedures are initiated
Sinus arrest criteria for classification
Regularly occurring PQRSTs both before and after the arrest period. No electrical activity occurs during the arrest period
Signs and sx's of sinus arrest
Depend on the length of the pause, decreased cardiac output if pause if 2 seconds long, periods of ischemia, hypotension, dizziness, and syncope
Caused by sinus arrest that lasts longer than 6 seconds. No electrical current is traveling through the cardiac conduction system
Explain the process of evaluating ECG tracings and determining the presence of dysrhythmias
Evaluating an ECG requires basic knowledge of waves, segments, and intervals of the tracing and the rate, rhythm, and regularity of the heartbeat
Describe the criteria used for classification of the dysrhythmias, including rhythm, rate, P wave configuration, PR interval measurement, and QRS duration measurement.
The process of evaluating an ECG tracing includes determining the ECG rhythm or regularity, determining the atrial and ventricular rate, identifying the P wave configuration, measuring the PR interval, measuring the QRS duration, and analyzing the configuration
What rhythm shows an irregularity during inspiration and expiration?
Tje normal PR interval is
0.12 and 0.20 seconds
If a QRS complex measures 0.12 seconds or wider, it most likely indicates
Delayed ventricular conduction
Sinus tachycardia may e a nl finding in persons as a result of
When sinus arrest continues for 6 sec or more it is considered
A medical emergency (code bleue)
The rhythm originating in the sinoatrial node that is considered nl is
Two rhythms originating in the sinoatrial nodes that only affect the heart rate are
S. Brady and Tachy