Download Unlocking The Key To Arrhythmias

Unlocking The Key To
Arrhythmias
Kristen Hallisey RN,BSN,CVN
Stress Lab Nurse
Goals
♦ Understand the normal electrical conduction
of the heart
♦ Setting up for ECG with lead placement
♦ Distinguish between atrial and ventricular
arrhythmias
♦ Identify lethal arrhythmias
♦ Understand basic treatments for arrhythmias
Electrocardiography
♦ The recording of voltage variations of the
heart plotted against time.
♦ ECG paper is graph paper with 1mm lines
horizontally and 1mm lines vertically.
♦ 1 millivolt change produces a 10mm stylus
deflection.(Each vertical line = .1 millivolt)
♦ The recorder moves at 25mm/sec(each
horizontal line = .04 seconds)
ECG
♦ 10 electrodes produce 12 leads
♦ Limb leads:I,II,III(bipolar)
♦ Augmented leads: aVR, aVL,
aVF(unipolar)
♦ Precordial
leads:V1,V2,V3,V4,V5,V6(unipolar)
ECG Relationship to Anatomy
♦ V1,aVR= right side of heart
♦ V2,V3,V4= transition between right and
left sides of the heart.
♦ V5,V6,I,aVL= left side of heart
♦ II,III,aVF = inferior heart
NORMAL ELECTRICAL
CONDUCTION
♦ SA node (Sinus Atrial)
♦ AV node (Atrio-Ventricular)
♦ Bundle of His
♦ Left and Right bundle
♦ Perkinje fibers
NORMAL MEASUREMENTS
♦ Measurements are in seconds
♦ PRI </= .20 seconds
♦ QRS </= .12 seconds
♦ Tracing paper has 1mm lines both
vertically and horizontally small box
measures 0.04 seconds, large box
measures .20 seconds
Normal Intervals
Interval
Large block
Small block
P
PR
QRS
Normal (sec)
0.2
0.04
0.11
0.12 to 0.20
< 0.10
Small Boxes
5
1
<3
3 to 5
< 2.5
ECG Timing
Irregular Heart Rate Determination
Normal Sinus Rhythm
♦ Regular Rhythm
♦ Rate 60-100 BPM
♦ One P wave per QRS complex
♦ PRI = < .20
♦ QRS= < .12
♦ No contradiction for stress test
Normal 12 lead ECG
SINUS ARREST
♦ One P to QRS
♦ Rhythm is irregular PRI .12sec - .20
sec, QRS < .12 sec
♦ Common causes: vagal stimulation,
acute MI, electrolyte imbalance.
♦ Treat patient if symptomatic.
ATRIAL ARRYHTHMIAS
♦ Initiated from the Atrium
♦ Atrial Tachycardia
♦ Atrial Fibrillation
♦ Atrial Flutter
♦ A-V Block
ATRIAL FLUTTER
♦ Atrial Rate > 150 BPM
♦ Regular Rhythm
♦ Saw Tooth in Appearance
♦ QRS Measurement </= .12
♦ Common causes: COPD, metabolic changes,
CHF
♦ Treat underlying cause
♦ May be contraindication for stress test
physician decision
ATRIAL FIBRILLATION
♦ Atrial rate > 400 BPM
♦ No PRI
♦ Rhythm is irregular
♦ Common causes: Digoxin toxicity, hypoxia,
intoxication, smoking, COPD, acute MI
♦ Most common treatment is Antiarrhythmics
and Anticoagulation to Cardioversion.
ATRIAL TACHYCARDIA
♦ Rate > 100 BPM
♦ Irregular Rhythm
♦ One P wave to QRS complex
♦ Common Causes: Sepsis, COPD,CHF,
electrolyte imbalance
♦ Treat the cause
♦ Stress test would mostly likely not be ordered
until patient was stable
Junctional Rhythm
♦ Regular R-R Rhythm
♦ Rate 40-60 BPM
♦ P wave is either inverted, or absent
♦ Can also be accelerated with rates 60-100
BPM
♦ Common causes: drug administration,
rheumatic heart disease, acute MI
♦ Only treat if patient is symptomatic
♦ Physician decision to proceed with stress test
VENTRICULAR ARRYTHMIAS
♦ Initiated from the Ventricle
♦ Ventricular Tachycardia
♦ Ventricular Fibrillation
♦ A-V Block
VENTRICULAR FIBRILLATION
♦ No measurable contraction
♦ CPR required
♦ Most lethal arrhythmia
VENTRICULAR TACHYCARDIA
♦ Rate > 100 BPM (usually 140-200 bpm)
♦ Regular Rhythm
♦ QRS > .12
♦ Common causes: Acute MI, hypoxia,
hypokalemia
♦ Treatment is based on patient’s stability
♦ Stress test would be stopped
A-V Blocks
♦ Conduction delay between Atria and
Ventricles
♦ Three types
♦ 1st, 2nd, 3rd degree
First Degree A-V Block
♦ One P wave per QRS complex
♦ PRI interval > .20
♦ Commonly caused by digitalis
administration
♦ Treatment observe patient possibly hold
digitalis
♦ Not a contradiction for stress test
Second Degree (Type 1)
♦ Also known as Mobitz I (Wenckebach)
♦ PR interval gradually lengthens until a QRS
complex is completely dropped
♦ Commonly caused by certain drug
administration, Vagal stimulation, Acute
inferior MI
♦ Treatment observe patient
♦ Physician decision to continue with stress test
Second Degree (Type 2)
♦ Known as Mobitz II
♦ More P waves than QRS complex
♦ Common causes: Acute MI, hypoxia, chronic
ischemia
♦ Treatment: Monitor patient and treat with
Atropine 0.5mg if symptomatic
♦ Physician may decide to hold stress if patient
is symptomatic
THIRD DEGREE A-V BLOCK
♦ Also called complete block. Atria and
Ventricles contracting independently
♦ Atrial rate 60-100 BPM with a regular rhythm
♦ Ventricular rate 40-60 BPM, QRS > .12 with a
regular rhythm
♦ Common causes: Large MI, hypoxia, cardiac
trauma, hypokalemia
♦ Treatment is pacemaker insertion
BUNDLE BRANCH BLOCK
♦ The bundle of His breaks off into the right and
left bundle. The left bundle further divides in
to anterior and posterior branches
♦ Common causes: Ventricular hypertrophy,
cardiomyopathy, ischemia, acute MI(inferior
RBBB, anterior LBBB), acute pulmonary
embolism
♦ Treatment is based on type of block and
patient condition
♦ Physician may choose not to stress with
RBBB because this could signify PE or IMI
CONCLUSION
♦ Physicians ultimately make the final
decision, however recognizing
arrhythmias can assist you in
understanding their decision.
Recognizing arrhythmias also enables
all of us to provide safe stress testing.