Are you ready to get started learning about ECG’s and interpreting the electrocardiogram? If so, then you’re in luck, because that is what this EKG study guide is all about.

As a Respiratory Therapist, depending on where you work, you will most likely have to perform EKG’s on the job. That is why it’s important for you to learn the ins and outs of electrocardiograms, the procedure, and how to interpret the results. 

The good news it — this study guide can help you do just that. Also note: this information correlates well well Egan’s Chapter 17 on Interpreting the Electrocardiogram, so you can use it to prepare for your exams. Are you ready to get started?

Practice Questions about EKG Interpretation:

Question 1

A P-R interval of .32 seconds would indicate:

  1. Disturbance in the heart’s conduction pattern
  2. Disturbance in ventricular contraction
  3. Area of ischemia
  4. Electrolyte imbalance


Question 2

A monitor that is worn for 24 hours to evaluate the performance of the heart during routine activities is known as

  1. Resting EGG
  2. Cardiac stress test
  3. Holter monitor
  4. Pacemaker


Question 3

A patient is experiencing chest pain and the physician wishes to determine the cause of the pain during exercise. However the patient is very feeble and cannot perform any exercise. Which of the following would you suggest for this patient?

  1. Cardiopulmonary stress test
  2. Echocardiogram
  3. Persantine Thallium stress test
  4. Holter monitor


Question 4

A patient is showing symptoms of a myocardial infarction, and the physician suspects that the left side (ventricle) of the heart is involved. Which of the following ECG leads will provide the physician with this information?

  1. Leads II, III, and aVF
  2. Leads V1 and V2
  3. Leads I and aVL
  4. Leads V5 and V6


Question 5

Depressed T waves on an EKG tracing represent:

  1. Myocardial injury
  2. Acute hypotension
  3. Myocardial ischemia
  4. Myocardial necrosis


Question 6

Elevated ST segments are indicative of what?

  1. Myocardial ischemia
  2. Certain cardiac medications
  3. Myocardial necrosis
  4. Conduction abnormality


Question 7

Every small square on the horizontal axis of the ECG grid paper represents ________ seconds.

  1. 0.06
  2. 0.04
  3. 0.02
  4. 0.10


Question 8

How many electrophysiologic phases are there in the action potential?

  1. 5
  2. 4
  3. 2
  4. 3


Question 9

In order to obtain a Lead I tracing, the electrode sensors provide:

  1. Right arm (negative): left leg (positive)
  2. Right arm (negative); left arm (positive)
  3. Left arm (negative) : left leg (positive)
  4. Left arm (negative); right arm (positive)


Question 10

In order to obtain a lead III tracing, the ECG sensor makes:

  1. Left leg (positive) Left arm (negative)
  2. Right arm (negative) Left leg (positive)
  3. Left leg (negative) Left arm (positive)
  4. Right arm (negative) Left arm (positive)


Question 11

In the normal conduction system, where does the electrical impulse of the heart originate?

  1. Purkinje fibers
  2. AV node
  3. SA node
  4. Bundle of His


Question 12

In which phase of repolarization is there a slow influx of calcium?

  1. Phase 1
  2. Phase 2
  3. Phase 0
  4. Phase 3


Question 13

Stimulation of the parasympathetic system causes a:

  1. Decreased heart rate
  2. Increased AV conduction
  3. Decreased conduction
  4. Increased contractility


Question 14

The P wave on an ECG tracing represents which of the following:

  1. Ventricular depolarization
  2. Atrial repolarization
  3. Atrial depolarization
  4. Ventricular repolarization


Question 15

The T wave on an ECG tracing represents:

  1. Ventricular repolarization
  2. Atrial depolarization
  3. Atrial repolarization
  4. Ventricular depolarization


Question 16

The ability of a cardiac cell to reach its threshold potential and respond to a stimulus or irritation is called:

  1. Contractility
  2. Conductivity
  3. Automaticity
  4. Excitability


Question 17

The main purpose of a cardiopulmonary stress test is to determine:

  1. Areas of ischemic blood flo
  2. Presence of congenital defects
  3. Presence of electrolyte abnormalities
  4. Criteria for a exercise program


Question 18

The normal P-R interval is:

  1. Usually between .12 and .20 seconds
  2. Less than .10 seconds
  3. Usually greater than .20 seconds
  4. Between .12 and .25 seconds


Question 19

The part of the autonomic nervous system that increases the heart rate is the:

  1. Conduction system
  2. Sympathetic system
  3. Parasympathetic system
  4. Purkinje system


Question 20

The type of electrodes most commonly used are _________________ and should be used ________________.

  1. Disposable, only once
  2. Reusable, more than once
  3. Reusable, after sterilization
  4. Disposable, more than once


Question 21

Two or more waveforms represents a:

  1. Waveform
  2. Interval
  3. Segment
  4. Complex


Question 22

What does the term repolarization mean?

  1. Cardiac cells returning to their resting membrane potential
  2. Contraction of the ventricles
  3. Cardiac cells responding to a trigger
  4. Contraction of the atria


Question 23

When continuous cardiac monitoring is used, what lead is often viewed?

  1. Lead I
  2. aVF
  3. Lead II
  4. Lead III


Question 24

When obtaining a 12-lead ECG, the correct number of electrodes to use is:

  1. 12
  2. 10
  3. 3
  4. 5


Question 25

Which of the following are characteristics of cardiac cells?

  1. automaticity
  2. excitability
  3. conductivity
  4. contractility


Question 26

Which of the following electrolytes are primarily involved in the cardiac cycle?

  1. Sodium
  2. Calcium
  3. Bicarbonate
  4. Potassium


Question 27

Which of the following electrophysiologic phases represent depolarization?

  1. 1
  2. 2
  3. 3
  4. 0


Question 28

Which of the following is NOT a common use for the 12 lead ECG?

  1. Preoperatively before surgery
  2. Diagnosis of heart disease
  3. To determine cardiac output
  4. To determine when to administer electrical shock


Question 29

Which of the following is counted vertically on the ECG grid paper?

  1. Voltage
  2. Time
  3. Dysrhythmias
  4. Isoelectric line


Question 30

Which of the following is the duration of each large square on ECG paper?

  1. .02 seconds
  2. .20 seconds
  3. .10 seconds
  4. .04 seconds


Question 31

Which of the following is the phase in which a strong stimulus may cause depolarization of cardiac cells?

  1. Relative refractory period
  2. Nonrefractory period
  3. All refractory periods
  4. Absolute refractory period


Question 32

Which of the following leads are considered bipolar leads?

  1. Lead II
  2. aVF
  3. V6
  4. Lead III
  5. Lead I
  6. V1


Question 33

Which of the following leads gives information concerning the lower surface of the heart or the inferior leads?

  1. Lead I
  2. Lead II
  3. Lead III
  4. aVL
  5. aVF


Question 34

Which of the following statements are correct when the cardiac cells are in the resting or polarized state:

  1. In this state, the inside of the cell is negatively charged with Ca+, and the outside is positively charged with Na+.
  2. In this state, the inside and outside of the cell have neutral balance.
  3. In this state, the inside of the cell is positively charged K+, and the outside is negatively charged with Na+.
  4. In this state, the inside of the cell is negatively charged with K+, and the outside is positively charged with Na+.


Question 35

Which of the following statements are true about the U wave of an ECG complex?

  1. U waves follow P waves
  2. U waves become visible only in the presence of electrolyte imbalances or heart disease
  3. U waves represent atrial repolarization
  4. U waves are very visible on an EKG tracing


Question 36

Which of the following uses the center of the heart as the negative reference point?

  1. V1
  2. Lead I
  3. V3
  4. Lead II
  5. V6


Question 37

Which of the following would be a normal duration for a QRS complex?

  1. .12 seconds
  2. .16 seconds
  3. .08 seconds
  4. .20 seconds


Question 38

Which type of ECG testing can be used to evaluate the heart while exercised?

  1. Treadmill stress test
  2. Holter monitor
  3. 12-lead EKG
  4. Echocardiogram


Question 39

Match each chest lead with the correct position.

  1. 4th intercostal space, left of sternum – V2
  2. Midway between V1 and V4 – V3
  3. Fifth intercostal space, midaxillary line – V6
  4. 4th intercostal space, right of sternum – V1
  5. Fifth intercostal space, midclavicular position – V4
  6. Fifth intercostal space, anterior axillary line – V5


Question 40

Using the ECG diagram provided, label the following waves, complexes, segments and intervals

  1. Q wave – 2
  2. T wave – 6
  3. PR Interval – 7
  4. P wave – 1
  5. R wave – 3
  6. ST segment – 9
  7. QRS Complex – 5
  8. QT Interval – 8


Question 41

Place the following components of the conduction pattern in correct order.

  1. Purkenji fibers
  2. AV Node
  3. Bundle of his
  4. SA Node
  5. Right and left bundle branches
  1. D, C, E, A, B
  2. C, D, E, B, A
  3. D, B, C, E, A
  4. B, C, A, E, D


Question 42

Which of the following leads would be required to view continuous ECG monitoring?

  1. aVL
  2. Lead I
  3. V2
  4. Lead II
  5. V2
  6. Lead III


EKGinexpensive, noninvasive, and easy to obtain
why do we use EKGchest pain, SOB, dyspnea, weakness, lethargy, and dizziness
What does EKG measurecardiac activity,repolarization and depolarization IT DOES NOT measure force of contraction of the heart
What is repolarizationresting…. positive outside of cell
What is depolarizationcontracting…..negative outside of cell
What is the normal pacemaker of the heartSA node (60-100
2nd pacemaker of heartAV node (40-60)
3rd pacemaker of heartBundle braches (30-40)
4th pacemaker of heartPurkinje (30-40)
Cardiac electrical pathwaySA node, AV node, bundle of HIS, R/L bundle branch, Purkinje Fibers
Nerve fibers within the AtriumSympathic (speeds HR) and parasympathetic (slows HR) when stimulated
Segmentportion of the baseline
Intervalcontains at least one wave
Rate calculationcount the number of large boxes between 2 R waves and then divide that number by 300 OR… memorize 300, 150, 100, 75, 60, 50
5 stepsrate, rhythym, p wave, pr interval, QRS complex
To find HRcount R’s then x by 10
Sbelow baseline….
Qbelow baseline… 1st one
RTallest point
recording techniques for ECGSnormally 12 leads, 10 leads are attached
holter monitoringUsed to take home and pt tape records when their palpation occurs
Usual electrical setting for defibrillation on adult200-360 J
What does the ECG measure/recordCardiac electrical activity Repolarization (relaxing) and depolarization (contracting)
When will ECG be indicatedPt complains of chest pain, SOB, dyspnea with palpations, weakness, lathargy, and dizziness
How many seconds does the small squares represent.04 seconds
How many seconds does the large squares represent.2 seconds (5 smaller boxes)
What is the speed25 mm/sec
What is cardiac electrophysiologybasic arrythymia interpretations (why the impulses are doing what they are doing)
Trace the normal cardiac stimulus as it spreads through the atria and ventriclesSA nodes, AV nodes, Bundle of HIS, R/L bundle branch, Purkinje fibers
Depolarizationcontracting When it goes up
Repolarizationrelexing when it goes down
Normal width of duration for QRS interval.05-.1 seconds
Normal width of duration for PR interval.12-.2 seconds
What is the noraml pace maker of the heartSA node
The rate of the SA node60-100
Rate of AV node40-60
rate of Bundle of branches30-40
rate of Purkinje30-40
2 nerve fibers within the right atrium that alter the HR when stimulatedParasympathetic and sympathetic
What does the Sympathetic do if stimulatedspeeds HR
What does the parasympathetic do if stimulatedslows HR
Holter monitoringMonitor patient wears and takes home and tape records everything, patient tapes when symptom occurs
echocardiographyultrasound used to see heart and it’s structure in motion (including valves)
Lubb heart soundheard when AV (mytral and tricuspid valves) close (LOUDER because pressure is higher in the left side of the heart)
Dubb heart soundheard when semilunar (pulmonatic and aortic valves) close
Murmursound heard inbetween lubb and dubb When it’s incompetent AV produces high pitched swooshing….. It is the backflow of blood through the AV into the atrium
Defibrillation setting for ventricular fibrillationenergy level of 120-200 J for adults and 2-4 J for children
3 lead system for lead placementWhite on upper right Smoke over fire(gray over red) clouds over grass (white over green) Brown on ground
P waverepresents atrial depolarization (contraction)
QRS complexrepresents ventricular depolarization and atrial replarization
T waverepresents ventricular repolarization
Q waverepresents conduction of impulse down the interventricular septum
U waverepresents repolarization of bundle of HIS and purkinje fibers
PR intervalbegining of P wave to begining of QRS (.12-.2 secs)— increase indicates 1st degree heart block
PR segmentend of P to beginning of QRS
QRS intervalsame as QRS complex it is .1 sec or less an increase indicates bundle branch block
ST segmentend of S to beginning of T
S1 heart soundsound of AV valves closing
murmurabnormal heart sound
holtermonitoring of occasional heart irregularites
voltagerepresented as vertical axis
P waveatrial contraction
S2 heart soundsound of semilunar valves closing
T waveresting of ventricles
Echocardiogram and cardiac dopplerstudy of heart structures and vlood flow
QRS complexventricle contraction
Which one would you likely see with acute hypoxiasinus tachycardia
Which rhythym will you see with chronic hypoxiasinus bradycardia
Which of the following criteria applies to third-degree block?There is no relationship between the P waves and the QRS complexes.
What is implied by an abnormally prolonged PR interval?Atrioventricular block
Why is the electrical impulse temporarily delayed at the atrioventricular (AV) node?To allow better filling of the ventricles.
Which of the following medications is used to treat sinus bradycardia?Atropine
What term is used to define the ability of certain cardiac cells to depolarize without stimulation?Automaticity
Which of the following ECG abnormalities is most life threatening?Elevated ST segment
Which of the following axis placements represents right-axis deviation?+120
ECG rhythm strip from an adult patient, you notice the following: regular sawtooth-like waves occurring at a rate of 280/min and a regular ventricular rhythm occurring at a rate of about 140/min. the most likely interpretation?Atrial flutter
What is suggested by inverted T waves on the ECGe?Myocardial ischemia
What structure normally paces the healthy heart?Sinoatrial (SA) node
Atrial flutter is considered to be a life-threatening arrhythmiFalse
Sources for the electrical impulse that triggers cardiac contraction that lie outside the sinoatrial node are referred to as ectopic foci.True
Which of the following is NOT a common characteristic of a premature ventricular complex (PVC)?Narrow QRS
Valvular defects in the heart can be detected with a 12-lead ECG.False
Which of the following is NOT a common cause of ventricular tachycardia?Pericarditis
At what part of the cardiac conduction system does the electrical impulse travel most rapidly?Purkinje fibers
What medication is most useful for the treatment of premature ventricular contractions?Lidocaine
The ECG you are looking at has one P wave for every QRS complex and the PR interval is 0.30 second. What is your interpretation?First-degree heart block
Which of the following waves represents depolarization of the ventricles?QRS wave
What is the width of the normal QRS complex?Not wider than 3 mm
Which of the following waves represents repolarization of the ventricles?T
For which of the following arrhythmias would an electronic pacemaker be indicated?Third-degree block
Your patient has a normal ECG reading. What does this finding tell you about the patient's likelihood of having a myocardial infarction in the immediate future?No predictive value
What is the normal maximum length of the P wave?3 mm
Which of the following clinical conditions is not associated with tachycardia?Hypothermia
The electrocardiogram (ECG) is primarily used to evaluate the patient with symptoms suggestive of acute myocardial disease.True
What is a possible serious complication associated with atrial fibrillation?Atrial thrombi
What is the normal period of time for the PR interval?Not longer than 0.20 second
What structure serves as the backup pacemaker for the heart?atrioventricular (AV) node
What parameter is measured on the vertical axis of the ECG paper?Voltage
An occasional premature ventricular complex (PVC) is not of major concern.True
What condition is often associated with right-axis deviation?Cor pulmonale
The QRS of an ECG falls on a dark vertical line of the ECG paper. Subsequent QRS complexes fall on every other dark line (10 mm apart). What is the ventricular rate?150/min
What type of medications may lead to first-degree heart block?ß-blockers
Normal sinus rhythmrate 60-100 Normal complexes
Sinus Bradycardiaeverything is normal but it’s a slower rate (longer difference between R’s)
PVC (Premature ventricular contraction)an abnormal complex originating in ventricle –wide QRS, –compensatory pause follows
Sinus tachycardiaSINUS= normal, rate greater than 100. (exercise, smoking, anxiety, etc) Faster (shorter distance between R’s)
PAC (premature atrial contraction)caused by irritability of atria -early contraction
Sinus arrhythmiarate varies between breathing.. common in children R-R intervals differenitate
Atrial fibrillationAtria depolarized (contracts) at high rate (up to 600/min)… Produces irregular, wavy pattern in place of normal P waves, — baseline is irregular
Atrial flutterAtria simulated about 300 times/min —charc by saw-toothed shape waves
Ventricular tachycardia3 or more consecutive PVC’s.. HR usually 120-200/min.. LIFE THREATENING… Wide QRS=PVC (heart does not have time to fill up so BP decreases).. P waves are hard to see
Ventricular fibrillationVentricles do not beat in coordinated fashion… no blood flow… PT unconcious..waves in irregular, CHAOTIC fashion
Asystoleflat line Do not shock unless last option do CPR instead
PEA (pulseless electrical activity)no pulse or cardiac output Pattern appears normal… assess with doppler
Acute hypoxiaoccurs first (tachycardia)
severe hypoxiaprolonged time (bradycardia)
What is an ECGan indirect measurement of the electrical activity within the heart
What do ECG’s not measurepumping ability, abnormalities of cardiac structure, probability of MI
Chief complaint suggestive of ECGchest pain, exert ional dyspnea, orthopnea, paroxysmal nocturnal dyspnea, pedal edema, fainting, palpations, nausea and indigestion in high risk pts
Past medical hx suggestive of ECGhx of heart disease, hx of cardiac surgery
physical exam suggestive of ECGunexplained tachycardia at rest, hypotension, <capillary refill, abnormal heart sounds, pedal edema, cool cyanotic extremities, abnormal heave or lift of pericardium, diaphoresis, JVD, abnormal sensorium, hepatojugular reflex, bilateral insp crackles
*SA Nodenormally is pacemaker, has greatest automaticity, causes depolarization (60-100bpm)
*AV Nodenormally acts as back up pacemaker (40-60 bpm)
electrical conduction system of the atriaSA node to the 3 internodal atrial conduction tracts leading to AV node and 1 intranodal conduction tract to left atrium (Bachman’s bundle)
Atrioventricular JunctionAV Node and bundle of His (.05 second delay)
electrical conduction of the ventriclesfrom bundle of his in AV junction to bundle branches (30-40 bpm) to purkinje network (30-40 bpm)
Systoleventrical contraction
Diastoleventrical relax
atrial kickcontraction of the atria (at latter end of systole) just before ventrical contraction-aids in ventrical filling and accounts for 10-20% of CO in healthy person
AV Node delay.05 seconds, delay before passing into bundle of his, allows for complete filling of ventricals before contraction (also protects vents from fast rates)
automaticitycells that have the ability to generate electrical activity spontaneously
pacemaker cellscells w/high degree of automaticity that provide electrical power to heart
myocardial cellscontract in response to elec stimuli and pump blood
ectopic impulseimpulse originating outside the SA Node
SA Node is stimulated by the sympathetic nervous system, what kinds of things can increase SA Node rate(fight or flight) stress, anxiety, exercise, medication. CHF, hyperthyroidism
what can slow the SA node rate (or stop it)vagal stimulation (parasympathetic), also drugs disease etc
coronary arteriessupply 02 and nutrients to heart, arise from descending aorta and branches to coronary vessels
Infarctionsblockage of one or more coronary vessels leading to regionalized tissue ischemia and tissue death
MI and ischemia cause whatdysrrhythmias and <CO
Hypoxia and ischemia of myocardium causes<PaO2, <HB, <perfusion
how can sympathetic stimulus cause ischemia>workload w/o concurrent blood flow (blocked coronary arteries)
what electrolyte imbalance cause dysrrhythmiaspotassium, magnesium and calcium are most common
poor cardiac output and HRto slow causes <output, HR to fast vents, not enough time to full so less blood pumping <CO
causes of dysrrhythmiashypoxia, ischemia, sympathetic stimulation, drugs, electrolyte imbalance
acetycholineneurotransmitter of the parasympathetic NS, aka cholinergic, <HR
norepinephrineneurotransmitter of the sympathetic NS, aka adrenergic, >HR, >contractility
alpha and beta adrenergic receptor sitesalpha are in blood vessels through out body and B receptor are in heart and lung only
receptor site mnemonic ABCDalpha constrict-beta dilate
heart receptoralpha and B1
lung receptorB2
blood vessel receptoralpha and B2
*4 major characteristics of cardiac cellsautomaticity, excitability/irritability, conductivity, contractility/rhythmical
action potentialelectrical charge passing through cell and propagating to other cells (all in one fashion)
polarizedresting state
depolarizationmuscle contraction(loss of negative charge)
re-polarizationreturn to resting state (negative charge returns)
*Pwave(.11 seconds) depolarization of the atria, impulse spreads across atria and triggers atrial contractions
*QRS complex(<.12) impulse spreads to ventricals, triggers ventrical contraction, (depolarization)
T-Waveventricals returning to resting state
*PRIPR interval, .12-.20, measures time from onset of atrial contraction to onset of vent contraction, aka time for elec impulse to spread through and AV node (3-5 small squares)
short PRI indicatesprogression of elec impulse is outside normal path
*long PRI indicatesdelay in conduction or AV block
normal QRS<.12
wide QRS indicatesoriginates in ventricular if supraventricular it has deviated from normal course
narrow QRSnormal, supraventricular
ST Segmentbegins at end of QRS and ends at beginning of Twave, normally flat
*elevated or depressed ST segmentdepressed ischemia, elevated MI
U-wavefollows Twave, may be seen or unseen, final phase of ventrical re-polarization
QT intervalfrom beginning of Q to end of T, should be ½ of R-R
long QT interval>1/2 of R-R (if HR is <80bpm), hypokalemia, hypocacemia, side effect of meds like quinidine
R-primea QRS complex that has a second positive deflection, the first is the R, the second is R-prime
S-primesecond S wave in QRS
normal mean axisbetween 0 and 90 degrees
Right axis deviationright vent is enlarged
Left axis deviationleft vent is enlarged
S&S of dysrrhythmiaschest pain, dyspnea, fine crackles, palpations, pale cool skin, dizziness/syncope, sense of impending doom, low BP-<90systolic, <LOC
interpreting dysrrhythmias can be accomplished in 3 levels1ventrical response (abnormal conduction), 2 categorize based on origin, 3 electro-physiology (pathway of conduction disturbance)
how is ventrical response determinedQRS complexes and pulse strength (to fast/slow, irritability, lethal, absent)
categories of origin areatrial, junctional, ventricular
electrophysiology of dysrrhythmiasectopic beat/rhythm, escape beats/rhythms, AV block, bundle branch block
*bradycardia rate<60
*tachycardia rate>100
irregular rhythmsmay be random or in patterns, ectopic beat, escape beat, second degree AV block, atrial Fib, sinus dysrrhythmias
*evaluate Pwavepositive, round, <.10, <2.5 mm tall, all should look alike
*odd shaped Pwaves are indicative ofatrial enlargement
*more than one Pwave may indicative ofatrial flutter (Pwaves look alike), atrial fib (Pwaves don’t look alike), 2nd or 3rd degree heart block
*evaluating PR intervalnorm .12-.20 seconds, >.20 is possible heart block (delayed AV node)
*evaluating QRSnorm <.12, wide w/bundle branch block, ectopic beat in vent (PVC’s), ventrical dysrrhythmias (vtach, idioventricular rhythm or premature ventricular complex), 3rd degree heart block
*evaluating ST segmentnorm is isoelectric(flat), elevated is myocardial injury, depressed is ischemia
cases of right axis deviationleft vent infarction, rt vent hypertrophy, COPD, pulm emboli, normal in infants,
causes of left axis deviationrt vent infarction, left vent hypertrophy, abdominal obesity, ascites, or ab tumor, pregnancy
*evaluating the Qwavenorm is <.04 and less than 1/3 amplitude of R, greater than 1/3 R is pathologic, indicative of new or old MI
*Right atrium enlargement is seen in ptschronic pulm hypertension (as with COPD)
*Right atrium enlargement is diagnosed byrt deviation of Pwave, tall Pwave or prominent or negative Pwave
*cor pulmonale (rt atrium enlargement) shifts axis howto the right
*absolute bradycardia<60 bpm w/no problems to pt (athlete)
*relative bradycardia<60 bpm not tolerated well by pt, pts with compromised cardiac function may cause hypotension, syncope, <CO, CHF or shock
transient bradycardia may be caused by>vagal tone from carotid massage, manipulation of tubes, suctioning, valsalva maneuver
long term bradycardia can be caused bydamage to SA node by MI
disease states that cause bradycardiahypothyroidism, hypothermia, hyperkalemia, meds
*sinus tachycardia100-150 BPM with SA node as pacemaker, most often caused by fever, pain, hypoxemia, hypovelemia, hypotension, sepsis, heart failure and suctioning
*respiratory meds that cause sinus tachycardiamethylxanthines (phosphodiesterase inhibitors) and B agonist
evaluating sinus dysrrhythmiasusually benign, everything is normal except rhythm, rhythm will be off (space between the R-R)
what is paroxysmal atrial tachycardia160-240 bpm, ectopic foci in the atrium takes over as pacemaker, sudden onset and ending, may cause hypotension, CHF, or ischemic episode, or recent/pre existing MI
danger of PAT (paroxysmal atrial tachycardia)>myocardial O2 demand but pump is ineffective because of rate, especially dangerous in pt with bad heart
Pt complaint with PATlight headed, palpations, possible fainting
causes of PATstress, mitral valve disease, rheumatic heart disease, digitalis toxicity, alcohol, caffeine or nicotine
evaluating PATrate 160-240 bpm, rhythm normal, Pwave abnormalities-hidden in QRS or if before QRS it appears pointed, can combine with Twave, PRI is usually not measurable
*atrial flutter pattern on ECG strip is caused byrapid firing of ectopic foci, sawtooth Pwave with normal QRS
*F-wavesflutter waves, caused by rapid contractions of atria upon stimulation by re-entry or accelerated automaticity
atrial flutter reduces CO howreducing atrial kick
mural thrombithrombi that form along the atrial walls (stagnated blood) during atrial flutter, migration may cause emboli
atrial flutter usually resolves howdeteriorates to atrial Fib or spontaneously returns to normal
caused of atrial fluttervalvular heart disease, MI, hypertension, cardiomyopathy, myocarditis and pericarditis
evaluating atrial flutterrate 180-400, rhythm is regular, Pwave is sawtooth can be 2:1, 3:1 etc, PRI not measurable (to many Pwave), QRS is normal <.12 sec
Atrial Fibrillationquivering of the atrials caused by multiple ectopic beats, causes complete loss of atrial pumping ability and increased risk of mural thrombi and emboli
caused of A Fibsame as a-flutter plus hyperthyroidism, pulm diseases and congenital heart diseases
evaluating for A-Fibrate can be as high as 400bpm, rhythm is irregular irregular, Pwave is chaotic and irregular, PRI is unmeasurable, QRS <.12
PVCectopic beat originating in ventrical, can occur in normal or diseased heart
common causes of PVC’sanxiety, caffeine, alcohol, tobacco and meds. Also seen in pts with HX of MI, heart disease, acidosis, electrolyte imbalance, CHF, and hypoxia
when are PVC’s dangerousmultiple PVC’s in less than 1 minute (indicates irritable vent area), couplets (2in a row), salvos (3 in a row), or R on T phenomenon
Salvos3 PVC’s in a row, also known as a run of Vtach
R on T phenomenonPVC’s occur during Twave of preceding beat, can cause PVC’s to turn into Vtach (when it happens Vtach QRS wave looks more rounded)
evaluating for PVC’srate is underlying, rhythm is regular, Pwave is not associated with PVC (others are normal), PRI not measurable (others are norm), QRS norm except with PVC>.12 abnormal look and premature, Twave is opposite direction of PVC (PVC up Twave down)
All PVC’s are followed by whatcompensatory pause (because they are premature)
Ventricular Tachycardiarun of 5 or more PVC’s, looks like a series of wide QRS’s w/no Pwave, tombstones or fireman hats
*what causes Vtachhypoxic heart, as with severe myocardial ischemia
evaluating Vtachrate 140-300 bpm, rhythm is regular, no Pwave with PVC, no PTI with PVC, wide QRS
Ventricular Fibrillationchaotic unorganized ventrical activity, wavy irregular pattern, no QRS, no rate, rhythm, Pwave or PRI
Asystolecardiac standstill-flatline-no pulse, dead
PEApulseless electrical activity, rare and usually follows an event like tension pneumo, cardiac trauma, severe electrolyte imbalance or acid-base disturbance
PEA rhythmany rhythm that does not produce a pulse except Vtach, Vfib and asystole
most common AV Heart block causesmeds like digitalis, damage from MI
1st degree AV heart block(mildest) prolonged PRI >.20 second delay at AV node
1st degree AV heart block causesmeds (digitalis), >vagal tone, hyperkalemia, myocarditis, and degenerative disease
evaluating for 1st degree heart blockrate normal, rhythm regular, Pwave normal, PRI prolonged (>.20), QRS norm at <.12
Second degree AV Block Type 1, aka Mobitz 1 aka Wenkebach(intermediate block) PRI gets long each beat until QRS is dropped, same causes as type 1
2nd degree AV Block type 2 aka Mobitz type 2rare and serious, many Pwaves with out QRS, PRI can be normal or prolonged, but is always constant
evaluating 2nd degree mobitz 2rate varies but ventrical is always less than atrial, rhythm is regular regular or regular irregular, Pwave looks normal but no QRS follows some.PRI is norm or long but all look alike, QRS <.12
causes of 2nd degree heart block type 2damaged bundle branch fallowing an MI or degenerative disease
3rd degree blockmost extreme and dangerous heart block. Conduction problem is in bundle of his (narrow QRS) or in bundled branches (wide QRS), complete block, no conduction atria and ventricals
causes of 3rd degree heart blocksinferior MI, increased vagal tone, myocarditis, digitalis toxicity, may be permanent condition following MI or degenerative disease
evaluating 3rd degree heart blockrate <60, rhythm is regular, Pwave is normal but not always followed by QRS, PRI varies many with no relationship to QRS, QRS is usually wide but can also be normal
idoventricular rhythmnormal pacemaker is not setting pace, trials norm but ventrical wave is irritable ectopic beat, looks like slow wide bizarre QRS, with brady, leads to rapid heart failure, (looks like row of slow moving PVC’s)
accelerated idoventricular rhythmvariation of idoventricular but rate is 60-100
evaluating idioventricular rhythmrate 30-40, rhythm is regular, Pwave is absent, PRI none, QRS >.12
Junctional rhythmarea of AV junction assumes pacemaker
causes of junctional rhythmAV node damage, electrolyte disturbance, digitalis toxicity, heart failure, valve disease, rheumatic fever
evaluating junctional rhythmrate 40-60, accelerated 60-100, junctional tachycardia >100, rhythm is reg, Pwave is absent, inverted or short, can be befor or after QRS, PRI if present is short, QRS <.12
Pwave following QRS is whatjunctional rhythm, shows retrograde conduction (up), and will be inverted (looks like ST segment is dipped)
If Pwave appears befor QRS in junctional rythmPwave is not responsible for QRS if PRI is less than .12
deviation of the ST segment up or down suggests whatabnormal myocardial perfussion and oxygenation (due to hyperkalemia), cardiac ischemia but no perminant damage
COPD causes what kind of axis deviationhyperinflation rotates heart & causes R axis deviation.
Cor pulmonale (R vent enlargement) causes what kind of deviationR axis deviation
COPD dysrhythmiasTachycardia, Multifocal atrial tachycardia, ventricle ectopic beats are most common (from hypoxemia & meds) & worsen at night due to hypoxemia.
Calculating EKG HRBetween R-R, add lg boxes at .20 each and sm boxes at .04 then divide into 60. 2lg + 3sm is 60/.2+.2+.04+.04+.04 equals 60/.52 is a HR of 115
Prolonged QRS .12-.10 causesR or L bundle branch block, IVCD or L anterior or posterior fascicular block.
QRS >.12Complete RBBB or LBBB (3rd degree block), IVCD, or PVC’S (v-tach & pacemakers)
IVCDintraventricular conduction delay.
Sick sinus syndromedisturbance of SA node causing marked variable in rhythm – cycles of brady and tachy.
Atrial tachySeries of 3 or more PAC’s (includes PAT-paroxysmal atrial tach)
Atrial flutter rate according to Karol’s handout250-350
A FibUncoordinated atrial depolarization’s
Junctional escape RhythmsInverted or no p-wave, AV node rhythm of 40-60
AV blockConduction block w/in AV node (sometimes bundle of his)
1st degree blockPRI >.20, caused by increased vagal tone, digitalis, beta- blockers, calcium channel blockers or ischemia damage.
2nd degree AV blockslow conduction at AV node so some don’t get through. Ventricle rhythm is < atrial rhythm.
2nd degree Type 1 (wenkebach)AV node block. PRI it elongates then drops QRS – most often seen in sleeping pt with high vagal tone (rarely is pacing indicated)
3rd degreecomplete block, but escape rhythms cause QRS but they originate in AV node, bundle of his or vent region. No synchrony between Pwaves & QRS atrial rhythm can be normal, but vent will be 30-40
SVT most often caused byreentry currents in atria or from vent to atria. Rate 140-250
VPB (Ventricular premature beats)Wide QRS, caused by eptopic foci in ventricle.
V TachCaused by aberrant vent automatically or intra-ventricular reentry, can be sustained or paroxysmal (short run) wide QRS 100-200 bpm.
V Fluttervent depolarizes >200/min
V FibUncoordinated vent depolarization’s
The 3 types of heart cells arepacemaker (automaticity), conducting (conduct electricity), and myocardial cells ( contract in response to electricity)
where is the greatest degree of of automaticitySA node-thus the pacemaker
what is the back up pacemakerAV junction
blocked coronary artery causes whatischemia and infarction leads to dysrrhythmias and <QT
what does the QRS reflect on ECGelectrical activity of the ventricals
during depolarization what happens in the myocardial cellsK- moves out and NA+ and CA+ moves in
during re-polarization what happens in the myocardial cellsK- moves back inside and NA+ and CA+ move to the outside
isoelectricflat (no positive of negative charge)
normal ECG has how many leads12, 6 limb (vertical plane) and 6 chest (horizontal plane)
what are the 6 limb leadsI, II, III, aVR, aVL, aVF
bipolar leadsleads I, II, and III, voltage is measured as a difference in between two electrodes
augmented leadsleads aVR, aVL, aVF are augmented by the machine because they are unipolar
frontal planevertical plane of the limb leads, measures up-down, right-left etc.
what are the chest leadsV1-V6
where are V1 and V2 located4th intercostal space V1 on the left and V2 on the right
where is V6 located5th intercostal in the midaxillary line (mid axillary would be if you cut body in half from top down, so mid axillary is under armpit) V3, V4 and V5 are located in between V2 and V6
depressed STischemia
elevated STinfarction, greater the height-greater the damage
elevated Tischemia (usually seen with depressed ST
significant increase in Q wave (.04) is indicative of whatinfarction
ECG’s are useful for assessing whatimpact of lung disease on heart, severity of infarction, heart rhythm, never pick pumping ability or QT
what clinical findings suggest the need for ECG’sorthopnea and syncope
what is the normal intrinsic rate of primary pacemaker60-100
what is the normal intrinsic rate of secondary pacemaker60-80
what does P wave representatrial depolarization
what does QRS representventrical depolarization
what does T wave representventrical re-polarization
normal PR interval.20
normal QRS<.12
QRS is equally spaced with 3 large boxes between, whats the rate100 (300/3 is 100)
QRS is equally spaced with 4 large boxes between, whats the rate75 (300/4 is 75)
prolonged PR intervalAV block
acute infarction looks like what on ECGelevated ST segment
difference between fibrillate and flutterflutter you can count and fibrillation is a quiver-chaotic, Ventrical fib and flutter originate low in the heart, so no QRS as with atrial fib and flutter (they have a QRS)
must know ID these strips and how to treat including medsbrady, sinus tach, PVC, fine and course VFib, asystol, depressed ST and elevated ST
1 small box on strip.04 seconds
1 large box on strip.20 seconds
calculating bpmadd the large boxes between R waves and devide into 300 so 300/3 is 100 bpm


Normal Sinus Rhythm•Heart rate: between 60 and 100 beats/min•PR interval: 0.12–0.20 s•QRS complex: <0.12 s•T wave: upright•ST segment: flat•R to R interval: regular (varying less than 0.12 s between QRS complexes)
Sinus Tachycardiaone abnormality—an elevated heart rate.•Heart rate: >100 beats/min•PR interval: 0.12–0.20 s•QRS complex: <0.12 s•T wave: upright•ST segment: flat•R to R interval: regular (varying less than 0.12 s between QRS complexes)
Sinus Bradycardiaone abnormality—a decreased heart rate.•Heart rate: < 60 beats/min•PR interval: 0.12–0.20 s•QRS complex: <0.12 s•T wave: upright•ST segment: flat•R to R interval: regular (varying less than 0.12 s between QRS complexes)
Sinus DysrhythmiaA sinus dysrhythmia has an irregular R to R interval. The heart is usually normal but may result in a sinus brady dysrhythmia (too slow) or sinus tachy dysrhythmia (too fast).•Heart rate: may be normal, slow, or fast•PR interval: 0.12–0.20 s•QRS com
Dysrhythmia – Sinus tachycardiaAnxiety, pain, fever, hypovolemia, hypoxemia; also side effect of bronchodilator medication
Dysrhythmia – Sinus bradycardiaHypothermia and abnormalities in SA node
Dysrhythmia – Sinus arrhythmiaVaries with breathing (increased rate during inspiration, decreased rate during expiration)—more pronounced with lung disease; associated with inferior wall myocardial infarction and increased intracranial pressure; also affected by medications.
In heart block, there is a problem with conduction between the SA node and the AV node. The width of the QRS complex provides information about the location of the ventricular pacemaker•A normal QRS interval (<0.12 s) indicates pacing from the AV junction—a junctional ectopic beat.•A wide QRS interval (>0.12 s) indicates pacing from cells in the ventricles—a ventricular ectopic beat; ventricular beats normally produce slower heart rate
First-Degree Heart Block•Heart rate: usually between 60 and 100 beats/min•PR interval: >0.20 s, but constant•QRS complex: <0.12 s•T wave: upright•ST segment: flat•R to R interval: regular (varying less than 0.12 s between QRS complexes
Second-Degree Heart Block Type I•Heart rate:irregular, usually between 60 and 100 beats/min•PR interval:the PR interval gradually gets longer after each beat until a P wave is not conducted to the ventricles (no QRS complex)•QRS complex:<0.12 s•T wave:upright•ST segment:flat•R2R:Irreg
Second-Degree Heart Block Type II•Heart rate: irregular and lower than normal•PR interval: normal or slightly prolonged•QRS complex: <0.12 s if block at bundle of His, wider complex if block below the bundle of His•T wave: upright•ST segment: flat•R to R interval: irregular
Third-Degree Block•Heart rate: irregular and lower than normal•PR interval: variable•QRS complex: <0.12 s if block at bundle of His, wider complex if block below the bundle of His•T wave: upright•ST segment: flat•R to R interval: regular
Causes of Heart Blocks – First-degreeInferior wall MI, complication of medications such as digoxin or beta-blockers
Causes of Heart Blocks – Second-degree type IAbnormality in AV junction, ischemia to right coronary artery
Causes of Heart Blocks – Second-degree type ILeft coronary artery ischemia or anterior wall MI
Causes of Heart Blocks – Third-degreeAcute MI (more common with inferior and posterior wall MI), drug toxicity (digitalis)


Egan’s Chapter 17 Practice Questions:


1. Atrial Fibrillation: -Atrial muscle quivers in an erratic pattern that does not result in a coordniation contraction., -No true P waves, -Ventricular rate may be abnormal resulting in an abnormal R-R interval.

2. Atrial Flutter: -Rapid depolarization of the atria resulting from ectopic focus that depolarizes at a rate of 250-350 times per minute., -P waves appear similar, -Sawtooth pattern, -Numerous p waves to each QRS complex, -R-R interval may be normal or vary, – causes may include: heart disease, stress, renal failure, and hypoxemia.

3. First-Degree Heart Block: -PR interval is longer than .20 seconds, -there is one p wave before each QRS complex, -Typically the QRS complex has a normal configuration, – R-R intervals are regular, -Common following an MI that damages the AV node, or may be a complication of certain medications such as digoxin or Beta blockers.

4. Normal Sinus Rhythm: – upright p wave that is identical from one complex to the next, -Consistent PR interval, – identical QRS complex no longer than .12seconds, – Flat ST segment, -R-R interval is regular and does not vary more than .12 seconds, -HR is between 60-100

5. Premature Ventricular Contractions: -cause a unique and bizarre QRS complex, which is wider than normal., -no p wave preceding and may occur as a single event, -PCV may occur at every other beat, every third beat, or as a run., – often occurs as a result of stress.

6. PR interval: the distance (time) between the start of atrial depolarization and the start of ventricular depolarization.

7. P wave: Wave of depolarization in the atria

8. QRS: Wave of depolarization over the ventricles

9. Second Degree Heart Block: Two types

10. Second Degree Heart Block Type II (Mobitz type II): -result of more serious problems such as MI or ischemia., -a series of nonconducted P waves followed by a P wave that is conducted to the ventricles., -PR interval for the conducted impulses is consistent.

11. Sinus Arrhythmia: -recognized by irregular spacing between the QRS complex., -R-R interval varies more than .12seconds, -may occur with the effects of breathing on the heart or as a side effect of medications such as digoxin., -Most times this doesn’t need treatment.

12. Sinus Bradycardia: -Heart rate is less than 60 but the rest of the tracing looks normal., -represents a significant clinical problem if it causes the patient’s blood pressure to drop significantly or causes symptoms such as fatigue, lightheadedness, or syncope., -Most often caused by hypothermia or abnormalities in the SA node.

13. Sinus Tachycardia: -Heart rate exceeds 100 but the rest of the ECG tracing looks normal, -Most often caused by anxiety, pain, fever, hypovolemia, or hypoxemia., -May also be caused from certain medications such as bronchodilators

14.Steps to reading an EKG: 1. Identify the atrial rate, 2. Measure the PR interval, 3. Evaluate the QRS complex, 4. Evaluate the T wave, 5. Evaluate the ST segment, 6. Identify the R-R interval, 7. Identify the mean QRS axis.

15. ST segment: the time from the end of ventricular depolarization to the start of repolarization.

16. Third Degree Heart Block: -most serious, – indicated the conduction system between the atria and ventricles is completely blocked, and impulses generated in the SA node are not conducted to the ventricles. , -no relationship between the P waves and the QRS complex. , -The P-P intervals and the R-R intervals regularly march out, but they have no correlation with eachother., -QRS complexes are normal if ventricles are paced by the AV node., -QRS complexes are not normal in configuration if the ventricles are paced by an ectopic site and are abnormally wide., -often caused by MI or drug toxicity.


17. T wave: Wave of repolarization over the ventricles

18. Type one second-degree heart block, (Wenckebach or Mobitz type I): -occurs when an abnormality in the AV junction delays or blocks conduction of some of the impulses through the AV node., -prolongged PR interval until one impulse does not pass on to the ventricles at all.(p wave that is not followed by a QRS complex).


Egan’s Chapter 17 Study Guide:


1. atrial fibrillation: P wave-NO TRUE, R-R ABNORMAL, STAGNATION OF BLOOD, atrial muscle quivers, no pattern, no coordination/contraction

2. ATRIAL FLUTTER: sawtooth baseline, numerous P-waves. Causes: heart disease, Renal failure, stress rapid depolarization of atrial from ectopic focus

3. First degree heart block: P wave-upright, PR interval- GREATER THAN 0.20 seconds, QRS – identical, R-R regular intervals, heart rate 60-100bpm, SA node delayed in passing thru AV node or bundle of his, COMMON AFTER MI, TREATMENT NOT NEEDED IF ABLE TO MAINTAIN BP

4. Normal sinus rhythm: P wave-upright, PR interval- consistent 0.12-0.20 seconds, QRS – identical, <.12, R-R regular intervals’ <.12, heart rate 60-100bpm

5. premature ventricular contractions (PVC): when part of the impulse conducting system or myocardium is diseased and triggers depolarization, causes pulse outside the SA-Node, WIDE QRS, NO P WAVE,
occurs with ectopic beats

6. second degree heart block, TYPE II, Mobitz: P wave-NON CONDUCTED more than QRS
PR interval- PROLONGED0.12-0.20 seconds
R-R regular intervals
heart rate 60-100bpm

7. second degree heart block, TYPE I WENCKEBACH: P wave-random MORE THAN QRS
R-R regular
heart rate 60-100bpm

8. sinus bradycardia: P wave-upright
PR interval- consistent 0.12-0.20 seconds
QRS – identical
R-R regular intervals

9. sinus bradycardia is treated with: atropine

10. Sinus Tachycardia: P wave-upright
PR interval- consistent 0.12-0.20 seconds
QRS – identical
R-R regular intervals

11. sinus tachycardia is treated with: Beta2 Adrenergic

12. THIRD degree heart block: P wave-upright NON CONDUCTED
PR interval- PROLONGED 0.12-0.20 seconds
R-R regular intervals
heart rate 60-100bpm
Total blockage,
atria/ventricles are independent with no relaionship

13. Ventricular Fibrillation: MOST LIFE THREATENING

14. Ventricular tachycardia: Most life threatening, zig-zag pattern
P wave-NONE
heart rate 60-100bpm

15. automaticity: ability for cells to contract, depolarize without stimulation

16. AV node: impulse over the ventricle allows for the ventricles to fill,
located at the intraventricular septum, the back up pacemaker

17. axis: the imaginary line that can be drawn between the positive and negative electrodes in leads I,II,II these axis deviations are seen in QRS complex

18. Axis evaluation: -determine the general direction of the flow during ventricular depolarization, -helps to ID hypertrophy of on of the ventricles

19. Bachmann bundle: wave of depolarization occurs over atria
produces the atrial contraction

20. bundle branches: moves the impulse to right and left ventricles

21. bundle of His: rapidly moves the electrical impulse to the bundle branches

22. cardiac cells: pacemaker,

23. conducting cells: cells that conduct the electrical impulse throughout the heart,
perkinje fibers

24. Cor Pulmonale: negative QRS complexes in lead I,
consistent with right axis deviation,
often seen in COPD

25. a defect in the impulse conducting system leads to: inadequate cardiac output

26. depolarization: contraction

27. Dubb: the sound heard at the close of the atrial valve

28. ECG: inexpensive
easy to use to evaluate pt
show electrical activity of the heart
has no predictive value

29. ECG paper speed: 25 mm/sec

30. Ectopic beat: any heart beat originating outside the SA node

31. Einthoven’s triangle: using leads I, II, III (bipolar leads) that are placed on Right arm, left arm and left leg

32.Elevated or depressed ST segment is common in: MI and is a life threatening arrhythmia

33. impulse conducting system has 3 types of cardiac cells: pacemaker cells
Purkinje cells
atrial and ventricular muscle cells

34. interpretation of ECG is completed by: a doctor

35. ischemia: horizontal ST segment that is above or below the baseline,
blood is not properly flowing to the heart

36. Leads V1 &V2: right ventricle,
placed on the right and left side of the sternum in the forth intercostal space

37. Leads V3 &V4: ventricular septum

38. Leads V5 &V6: left ventricle

39. Lubb: is the sound heard as the bicuspid and tricuspid valve close

40. Multifocal PCVs or the R on T phenomenon with PVCs: this serious condition shows a response to ischemia of the myocardium

41. Myocardial cells: cells that contract in response to electrical stimuli
pump blood,
atrial and ventricular muscle cells

42. pacemaker cells: specialized cells that have a high degree of automaticity
provide electrical power for the heart
SA node and AV node

43. parasympathetic nervous system: slows the heart rate and AV conduction

44. PR interval: 0.12-0.20 seconds,
total atrial electrical activity prior to activation of the bundle of His,
ventricular branches,
purkinje fibers,
shows heart block problem if interval is long

45. Pulseless electrical activity PEA: ECG does not generate a pulse, rare

46. Purkinje fibers: finger like projections penetrate the ventricles, stimulate contraction of the myocardium from apex to base,
coordinates contraction of ventricles

47. P wave: atrial depolarization,
0.08-0.11 seconds

48. QRS complex: ventricle depolarization,
<0.12 seconds,
shows problem in ventricles

49. QT interval: <0.38 seconds,
represents the total ventricular – QRS complex, ST segment & T wave

50. repolarization: relaxing

51. Resting membrane potential: the electrical difference between the electrolytes inside the cell membrane and outside of the cells membranes,
measured in millivolts,
electrolytes responsible are K+, Na+, Ca2+, myocardial cells are about -90mV

52. SA node: impulse is generated to right atrium,
this is also called the pacemaker of the heart, automatic,
located in the upper right part of the atrium,
this is where the heart beat starts.


53. sinus arrhythmia: P wave-upright
PR interval- consistent 0.12-0.20 seconds
heart rate 60-100bpm

54. Sinus bradycardia clinical problem if: causes the pt blood pressure to decrease significantly or if pt is symptomatic

55. ST segment: Refractory period,
<0.12 seconds,
normal is the isoelectric line,
abnormal shows(elevated or depressed) ischemia and MI
potentially life threatening

56. T wave: Ventricle repolarization, <0.20 seconds,

57. Where is atrial repolarization seen on an ECG?: it is obscured by the QRS complex

58. Why do RT need to understand ECG: able to recognize serious arrhythmia’s
able to respond quickly and appropriately

Final Thoughts

So there you have it! That wraps up our study guide on EKG’s and interpreting the electrocardiogram. I truly hope that this information was helpful for you and I hope you can use it to ace your exams in RT school. Not only that — I hope the information sticks with you throughout your career as a Respiratory Therapist. Thank you so much for reading and as always, breathe easy my friend.