Graphic representation of the electrical impulses of the heart to ID arrhythmias
What is the path of electrical conduction through the heart?
SA node-->AV node-->Bundle of HIS-->L & R Bundle Branches-->Purkinje Fibers
What do P waves represent?
How should a normal P wave look?
Nice & rounded
What follows a P wave?
What does the PR interval represent?
Slowing of conduction through the AV node
What does the QRS complex represent?
Ventricular depolarization followed by ventricular contraction
What does the ST segment represent?
Initiation of ventricular depolarization
How should the ST segment look?
On a normal EKG, how should the RR interval be?
Why is a basic understanding of single-lead EKG's necessary?
It can help a PT determine the safety of certain interventions in pt's w/abn's
What is a single-lead EKG used for?
To detect rate & rhythm abn's
Can a single-lead EKG detect ischemia?
Where are single-lead EKG's most commonly done?
*ICU *Step-downs *CPPT rehab
What us a twelve-lead EKG used for?
To determine ischemia or infarction
When is a 12-lead EKG ordered?
When there's a change in pt condition or suspected ischemia
V1 & V2
V3 & V4
Anterior Left Ventricle
V5 & V6
Lateral Left Ventricle
On an EKG, what is indicated by heightened R waves & deeper S waves?
How can ventricular hypertrophy be ID'ed on an EKG?
Look for heightened R waves & deeper S waves
True or False:Ventricular hypertrophy can be seen in both healthy & sick pt's.
W/what cardiac dysfxns can ventricular hypertrophy be present?
LV dysfxn & CHF
On an EKG, what indicates myocardial ischemia?
ST depression or T wave inversion w/angina
What is ST depression or T wave inversion indicative of?
On an EKG, what indicates an MI?
What is ST elevation indicative of?
Is ST elevation a medical emergency?
What length of time is 1 small box equal to?
What length of time is 1 big box equal to?
What length of time is each tick mark equal to?
What is one method of calculating HR?
Count # of QRS complexes in 6sec & multiply by 10
What is the square counting method good for?
How do you do the square counting method?
1) 1st thick line after QRS complex is 300 2) Count backwards in the sequence at each thick line (300-150-100-75-60-50) 3) Stop when you get to the next QRS complex. The # you're at is the HR
Step by step approach for interpreting EKG's:
*Are the RR intervals equal? *Does each beat begin w/a P wave? *Is every P wave followed by a QRS complex? *Is each QRS complex followed by a T wave? *Are the PR intervals equal? *Do all the QRS complexes look the same?
Characteristics of normal sinus rhythm
*P waves are constant & upright *Each P wave is followed by a QRS complex *Each QRST is followed by a O wave *PR interval is constant at .12-.2 sec *HR is 60-100bpm
What are T-wave changes indicative of?
What do U waves represent?
Are U waves normal to see?
Yes but they can also be indicative of hypokalemia, hypercalcemia, & MI
What are Q waves indicative of?
Absence of electrical activity so sign of previous MI
What is a widened QT interval indicative of?
Impending ventricular arrhythmia
What is a widened QT interval commonly misdx'ed as?
Any rhythm other than NSR
SA node is intact & working
Premature impulses that arise from the AV node or junctional tissue
What is the most dangerous location for arrhythmia & why?
Ventricle bc it can alter cardiac output
Electrical activity outside of the normal pathways
What causes sinus tachycardia
*Stimulants *Stress *Fever *Hemmorrhage
What is the tx for sinus tachycardia?
Eliminate the cause & beta-blockers
What causes sinus bradycardia?
*Beta-blockers *Incr vagal stimulation *Being a highly trained athlete
Sx's of sinus bradycardia
*Syncope *Dizziness *Angina *Diaphoresis
Tx for sinus bradycardia
Do nothing unless pt is symptomatic *Atropine or pacemaker
Inconsistent RR intervals
What can cause sinus arrhythmia?
True or False: Normal respiration can cause sinus arrhythmia.
What population is sinus arrhythmia common in?
Young/elderly at rest
What is sinus arrhythmia associated w/?
*Morphine or digoxin toxicity *Infection *Fever
No true P waves, but rather flutter waves so there will be multiple P waves before every QRS
What can cause atrial flutter?
*Rheumatic heart disease *Mitral valve disease *Hypoxemia
Tx for atrial flutter
*Meds (digoxin, verapamil, & beta blockers) *Cardioversion
Does atrial flutter effect ventricular rate?
No true P wave leaving a flat/wavy baseline between QRS complexes & SA node is no longer doing its job so AV node takes over
Describe the RR interval seen w/A-fib
What causes A-fib?
*Age *Ischemia/Infarction *Stress *CHF *Renal failure
Why is A-fib a problem?
Bc it can decr CO by 15-30%
What is A-fib very dangerous & why?
Tachycardia bc it can cause stagnant blood-->Excess coagulation-->Clot
Until what point can a pt w/a-fib exercise until?
Ventricular rate >120bpm at rest
Tx for a-fib?
Blood thinners, anticoags, & ablation
Occurs when cardiac electrical impulse is delayed/blocked w/in the AV node, bundle of HIS. or purkinje system
1° Heart Block
Delay caused by conduction at the AV node or bundle of HIS so PR interval becomes longer by .2 sec
2° (Mobitz 1/Wenckebach) Heart Block
Progressive elongation of PR interval followed by a dropped (missing) QRS complex
What part of the heart has a problem during 2° (Mobitz 1) heart block?
Tx for 2° (Mobitz 1) heart block
Nothing unless pt is symptomatic
2° (Mobitz 2) Heart Block
Normal PR interval but beats are dropped-->Intermittent non-conducted P waves so there's 2 P waves for every 1 QRS
What part of the heart has a problem during 2° (Mobitz 2) heart block?
Bundle of HIS or Purkinje Fibers
What can 2° (Mobitz 2) heart block progress to?
Complete heart block or cardiac arrest
Tx for 2° (Mobitz 2) heart block
3° (Complete) Heart Block
SA node generates impulse, but its not conducted to the ventricles
What will 3° heart block look like on an EKG?
*Complete lack of relationship between P waves & QRS complexes *Escape rhythms-->2 independent rhythms on EKG *Regular P waves & QRS complex, but variable PR interval
What can cause 3° heart block?
Ischemia or MI
Sx of 3° heart block
*Severe bradycardia *Hypotension *Hemodynamic instability
Tx for 3° heart block
*Electrical pacing by dual chamber artificial pacemaker
Premature Ventricular Contractions
Ectopic focus generating an impulse from somewhere in the ventricles
Regarding PVC's, when should you be concerned?
When a pt has 3 PVC's in a row or 6 in a minute
What can PVC lead to?
What can cause PVC's?
*Stress *Caffeine *Nicotine Sensitivity *Electrolyte imbalance *Ischemia *Myocardial Irritation *Cardiac disease
Sx's of PVC's
*Feeling of skipped beat *Anxiety *SOB *Dizziness
Tx for PVC's
*Tx underlying cause *Meds *Supplemental O2 for pt's w/lung disease
In pt's lung disease, what can PVC indicate?
3+ PVC's in a row w/HR >120bpm
Why does V-tach occur?
Rapid firing from a single ventricular focus
How can you ID v-tach on an EKG?
No P waves & will look like a bunch of PVC's in a row
Self-termination in <30sec
V-tach lasts >30sec
Causes of V-tach
*Ischemia *Acute infarction *CAD *Heart disease *Med rxn to digoxin or qunidine *Athletes w/electrolyte imbalance
Sx's of V-tach
*Weak thready pulse *Dizziness *Syncope *Disorientation
Tx for V-tach
*Immediate pharmacologic intervention *Cardioversion *Defibrillation
Torsade de Pointes
Unique configuration of V-tach; Twisting of the points around the isoelectric line
What is Torsade de Pointes associated w/?
Prolonged QT interval
Tx for Torsade de Pointes
Erratic quivering of ventricular musculature-->Multiple ectopic foci firing simultaneously, so there's no CO
On an EKG, what does a vertical spike indicate?
Pacemaker activity (V-fib)
How does a pacemaker fxn during V-fib & what will it look like on an EKG?
1) It emits a pulse when a native P wave or QRS complex isn't sense w/in a certain amount of time 2)Atrial pacer spikes are seen right before the P wave 3)Ventricular pacing is seen right before the QRS complex
What is V-fib almost always associated w/?
Tx for V-fib
*Always de-fib V-fib *CPR *O2