cardiac cardiacmonitoring. types of cells in the heart

cardiac cardiac monitoringmonitoring

Types of cells Types of cells in the heartin the heart

Types of cells in the heartTypes of cells in the heart

Pacemaker cells:

These are the cells that actually generate the electrical impulse in the heart. They have the ability to spontaneously generate electrical impulses (automaticity).

The intrinsic pacemaker sites we mostly talk about are the pacemaker cells being in the SA node, AV node / Bundle of His and Ventricles. However, ectopic foci can be located throughout the heart.

If anyone of these pacemaker cells creates an electrical impulse, it has a possibility to depolarize the heart.

Conduction system

Pacemaker cellsthroughout theheart...

Myocardial cells:

The myocardial cells contain contractile filaments.

When the cells receive electrical stimulation they contract.

The myocardial cells make up the muscular layer of the ventricular walls.

Myocardial cells do not normally generate spontaneous electrical activity.

Types of cells in the heartTypes of cells in the heart

Conduction pathway of the heartConduction pathway of the heart

SinoAtrial NodeMain Pacemaker Site of the heart

Depolarizes at an intrinsic rate of 60-100

times per minute

Internodal pathways Bachman’sBundle

AtrioVentricular NodeSecond Pacemaker Site

Backup pacemaker sitewhich depolarizes 40-60time per minute.

The AV node, while being a secondary pacemaker site for the heart is also a delay point for the depolarization.

As the electrical current hits the AV node it is delayed (we see this as the PR segment). This delay allows the Ventricular depolarization to occur a short while after the atrial depolarization.

If this delay point was not present, the specialized tissues of the Cardiac conduction system would depolarize the heart all at once and, in effect, be an ineffective physiologic pump.

Bundle of HIS

Left & RightBundle Branches

PurkinjeFibers

Measuring the electrical Measuring the electrical conduction of the heart conduction of the heart

based on bipolar based on bipolar calculationscalculations

Bipolar calculationsBipolar calculations

Measures the electricity going towards the (+) electrode andsubtracts amount electricity

going towards the (-) electrode.

If the answer shows moreelectricity going towards the (+) then there will be

a positive deflection. Ifmore electricity is going

towards the (-), then there will be a negative deflection.

Bipolar calculationsBipolar calculations

Cardiac monitoring requires a minimumminimum of 3 leads, However,

Most monitors now have 4 lead wires.

These are the standard three lead electrodes.

•Negative electrode (RA)

•Positive electrode (LL)

•Ground electrode (LA)

The extra electrode is the RL electrode. It is usually green, but not always.

•Green electrode (RL)

Negative electrode (RA)

Positive electrode (LL)

Ground electrode (LA)

Green electrode (RL)

Three Lead machines RA, LL, LA will show you leads I / II / III

The additional lead will allow you to see:•Augmented voltage Right (aVR)•Augmented voltage Left (aVL)•Augmented voltage Foot (aVF)

ECG Leads

lead positions we should lead positions we should know aboutknow about

Lead placement - Lead ILead placement - Lead ILooking at the anterior heartLooking at the anterior heart

GWhen we switch lead views on the cardiac monitor, the machine will automatically change polarity of the electrodes as it needs to.

Lead placement - Lead IILead placement - Lead IILooking at inferior heart, mainly LVLooking at inferior heart, mainly LV

G

Most commonly monitored lead during transport

Lead placement - Lead IIILead placement - Lead IIILooking at inferior heart, mainly LVLooking at inferior heart, mainly LV

G

Lead placement Lead placement Lead MCL 1 (V4R) Looking at RVLead MCL 1 (V4R) Looking at RV

The goal of interpreting ECG’s is to help guide the practitioner to a Diagnosis. This in order to facilitate treatments and interventions that will benefit the patient.

Lead V4R / MCL 1 (modified chest lead 1) allows us to have a look at the right ventricle. This will either rule out RV involvement in an inferior AMI, or show us that there is RV infarct involvement.

There is a difference in placement for this lead configuration. A new electrode must be placed at the right 5th intercostal space in the mid clavicular line. This lead also must be viewed using lead III to ensure proper lead polarity, Monitors are not set up for this lead in a default setting.

Don’t worry, you do not need to RV involvement issues right now……RV involvement is covered in future presentations.

Lead placement - Lead MCL 1 / V4RLead placement - Lead MCL 1 / V4RLooking at RVLooking at RV

EKG PaperEKG Paper

EKG paperEKG paper

•Specialty paper which imprints lines via a heated stylus

•Records at 25 mm/sec. (universal speed)

•Each manufacturer usually has it’s own style of paper

EKG squaresEKG squares

Horizontal Axissmall square equals 0.04 sec

large square equals 0.2 seconds (0.04 X 5)

Vertical AxisEach large squareequal 0.5 millivolt

0.04s

0.2s

EKG paper

These time values are crucial in calculating the various intervals and waveforms of the “P Q R S T” segment.

EKGEKG in relation to thein relation to the

conduction systemconduction system

The heart at rest, no electrical activity, therefore no deflectionsfrom the isoelectric line. The SA node is building up to depolarize.

Isoelectric line

Threshold is reached and depolarization conducted through the atria. This produces a positive deflection.

As the atrium finishes depolarizing, the electrical impulse ischanneled back to the AV node.

We call this first deflection the“P” wave and it denotes the

depolarization of the atria.

The P wave, in a normal EGC is the first positive deflection off of the isoelectric line.

As the electrical charge travels through the AV node, there is no measurable electrical movement. Therefore the EKG tracing stays on the isoelectric line

The PR interval is from the beginning of the “P” wave to the first deflection of the “QRS” complex

P-R Interval (PRI)

PRI should be between 0.12s – 0.20sAs the heart speeds up the PRI may shorten,

but >0.20s PRI is a conduction delay.

“Q”

“R”

“S”

QRS complex - we see the depolarization travel down and through the ventricles.

This complex is calledthe “QRS” complex and denotesthe depolarization of the ventricles

QRS ComplexQRS Complex

The T wave after the QRS complex indicates therepolarization of the ventricles

T- WaveT- Wave

Naming WaveformsNaming Waveforms

• We have seen the P wave, Q, R, S We have seen the P wave, Q, R, S complex and T wave.complex and T wave.

• It is important to know that It is important to know that notnot all all

EKG readings have all of these EKG readings have all of these waveforms.waveforms.

Naming WaveformsNaming Waveforms

• The QRS complex is very easy to visualize, and The QRS complex is very easy to visualize, and just before the QRS complex, there should be a “P just before the QRS complex, there should be a “P wave”.wave”.

• P wave characteristicsP wave characteristics• Smooth and roundedSmooth and rounded• No more than 2.5 mm in heightNo more than 2.5 mm in height• Should be positive, however in different some Should be positive, however in different some

rhythms it may be absent, inverted, notched or rhythms it may be absent, inverted, notched or biphasic (above and below isoelectric line).biphasic (above and below isoelectric line).

• The P wave represents Atrial depolarization.The P wave represents Atrial depolarization.

Naming WaveformsNaming Waveforms

• After the P wave is the PR segment.After the P wave is the PR segment.• A segment is a line between two waveforms.A segment is a line between two waveforms.• The PR interval (PRI) is composed ofThe PR interval (PRI) is composed of

• P waveP wave• PR segment PR segment

• PRI characteristicsPRI characteristics• 0.12s – 0.20s in duration0.12s – 0.20s in duration• As heart rate increases, PRI length decreasesAs heart rate increases, PRI length decreases• Normal PRI indicates normal conduction through Normal PRI indicates normal conduction through

AV node & bundle of his.AV node & bundle of his.

Naming WaveformsNaming Waveforms

• The first negative deflection after the PRI is the Q The first negative deflection after the PRI is the Q wave. The Q wave may not be in every EKG wave. The Q wave may not be in every EKG reading you takereading you take..

• A Q wave is ALWAYS a negative deflection and it A Q wave is ALWAYS a negative deflection and it represents the depolarization of the intraventricular represents the depolarization of the intraventricular septum. (tissue between ventricles).septum. (tissue between ventricles).

• It is important to understand the difference It is important to understand the difference between “normal” Q waves and “pathologic” Q between “normal” Q waves and “pathologic” Q waves. We will discuss this in a few slides.waves. We will discuss this in a few slides.

Naming WaveformsNaming Waveforms

• The first positive wave after the Q (or pri if no Q) The first positive wave after the Q (or pri if no Q) is the R waveis the R wave..• The R wave is a large triangular shaped wave.The R wave is a large triangular shaped wave.

• The next negative wave after the R wave is the “S” wave.The next negative wave after the R wave is the “S” wave.• The S wave is a large triangular shaped wave as well.The S wave is a large triangular shaped wave as well.

• The QRS complex represents ventricular depolarizationThe QRS complex represents ventricular depolarization..

““Q” wavesQ” waves

• A normal Q wave should be less than 0.04s in A normal Q wave should be less than 0.04s in duration and less than 25% of the amplitude duration and less than 25% of the amplitude (height) of the “R” wave.(height) of the “R” wave.

• If a Q wave is greater than 25% in height of the R If a Q wave is greater than 25% in height of the R wave and longer that 0.04s it is considered wave and longer that 0.04s it is considered pathologic. pathologic.

• This is generally considered an indicator of an old This is generally considered an indicator of an old MI or when sections of the myocardium are dead.MI or when sections of the myocardium are dead.

““Q” WavesQ” Waves

Normal QNormal Q

““Q” WavesQ” Waves

Pathologic “Q” Pathologic “Q” waveswaves•Greater than 25% height of Greater than 25% height of the “R” wave.the “R” wave.

•Greater than 0.04s Greater than 0.04s

QRS ComplexQRS Complex• Characteristics of the QRS complexCharacteristics of the QRS complex• Predominantly positive in leads I / II / IIIPredominantly positive in leads I / II / III• No longer than 0.12s (three small squares)No longer than 0.12s (three small squares)

R wave

S wave

Measured from first departure of QRS to rejoining isoelectric line

Abnormal QRS complexesAbnormal QRS complexes

• Now that we have seen the proper QRS complex here Now that we have seen the proper QRS complex here are examples of abnormal complexes.are examples of abnormal complexes.

A single positive deflection leaving then returning to the A single positive deflection leaving then returning to the isoelectric line is called an R wave. isoelectric line is called an R wave.

Abnormal QRS ComplexesAbnormal QRS Complexes

A single negative deflection after the PRI, being the only component of a “QRS” is called a

“Q/S” complex

This is the only waveform that has this naming process applied to it.

Abnormal QRS complexesAbnormal QRS complexes

This complex looks similar to the “Q/S” complex, but it is not.

It has a tiny “R” wave.

Naming WaveformsNaming Waveforms• The “J” point, this is the point where the QRS complex rejoins the isoelectric line. The “J” point, this is the point where the QRS complex rejoins the isoelectric line.

• The “J” point will come in to play as a reference point in advanced ECG recognition in The “J” point will come in to play as a reference point in advanced ECG recognition in terms of Cardiac Ischemia and Injury.terms of Cardiac Ischemia and Injury.

J point

Calculating the heart rate.Calculating the heart rate.

Calculating the EKG rateCalculating the EKG rate

Method 1: Count the number of large squares betweeneach QRS complex and divide that by 300

4 large squares (heavy lines). 300 divided by 4 = 75

1 2 3 4

Method 2: Count the number of QRS complexes in a 6 second strip (30 large squares) and multiply by 10

7 QRS in 6 second strip= 70

Calculating the EKG rateCalculating the EKG rate

1 2 3 4 5 6 7

Method 3: Use the 300, 150, 100, 75 , 60, 50 methodPlace the numbers in succession from thefirst solid line after the QRS

Next QRS lands on 75, therefore rate is 75Remarkably similar to Method #1, just taking the division out…….

300

150

100

75

Calculating the EKG rateCalculating the EKG rate

• When using any of the three methods When using any of the three methods remember that they will only work for: remember that they will only work for:

REGULAR RHYTHMSREGULAR RHYTHMS

• When calculating an irregular rhythm for a When calculating an irregular rhythm for a stable patient, the best way is to take your stable patient, the best way is to take your patients pulse for the entire minute.patients pulse for the entire minute.

• Remember that even with that count that Remember that even with that count that is only for that minute and the next minute is only for that minute and the next minute will be different. Always reassess irregular will be different. Always reassess irregular pulses on a regular basis.pulses on a regular basis.

Calculating the EKG rateCalculating the EKG rate

We can calculate EKG rates. We can calculate EKG rates.

We know the waveforms of the We know the waveforms of the EKG. EKG.

Now, We need to identify where Now, We need to identify where the impulse originated from and the impulse originated from and how it looks on the normal EKGhow it looks on the normal EKG

3 main areas that the EKG 3 main areas that the EKG normally originates fromnormally originates from::

•AtriumAtrium•A.V. node / Bundle of A.V. node / Bundle of HisHis

•VentriclesVentricles

AtriumAtrium

If the impulse originates in the SA node, you should If the impulse originates in the SA node, you should see a “Normal P” wave, “(Q)RS” and “T” wave. see a “Normal P” wave, “(Q)RS” and “T” wave.

The normal rate from the atria (SA node) is 60-100The normal rate from the atria (SA node) is 60-100

Low A.V. node Low A.V. node (junction)(junction)

If the impulse originates If the impulse originates lowlow in the A.V.node, in the A.V.node, you will see a QRS complex you will see a QRS complex

and “T” wave, but no “P” waveand “T” wave, but no “P” wave

Or...

Hidden “p” wave

High A.V. node High A.V. node (junction)(junction)

A retrograde (inverted) “P” wave. Caused by higher A retrograde (inverted) “P” wave. Caused by higher impulse Foci, higher in the AV nodeimpulse Foci, higher in the AV node

VentriclesVentricles

If it impulse originates in the ventricles, If it impulse originates in the ventricles, Most commonly you will see a wide bizarre QRS complex Most commonly you will see a wide bizarre QRS complex

and “T” waveand “T” wave

What are the What are the steps to analyze an EKG? steps to analyze an EKG?

Steps for proper interpretationSteps for proper interpretation

1.1. Rhythm: Regular or IrregularRhythm: Regular or Irregular

2.2. Rate: How fast is the heart depolarizingRate: How fast is the heart depolarizing

3.3. Is there a P wave? Is there a P wave? Is it upright, round, and one before every QRS complex?Is it upright, round, and one before every QRS complex?

4.4. How long is the PRI?How long is the PRI? Is it < or > 0.20s?Is it < or > 0.20s?

5.5. Is the QRS complex narrow or wideIs the QRS complex narrow or wide**? ? >0.10s / 0.12s>0.10s / 0.12s

6.6. Is the T wave present and normal?Is the T wave present and normal?

* Depending on Cardiology books wide QRS can be defined as wide at > .010s* Depending on Cardiology books wide QRS can be defined as wide at > .010s

Steps to proper interpretationSteps to proper interpretation

• Follow the steps with every rhythm you Follow the steps with every rhythm you come across, this should assist you in come across, this should assist you in interpreting rhythms correctly.interpreting rhythms correctly.

• Consistency is the key.Consistency is the key.

• Eventually you should be able to read Eventually you should be able to read actual strips off the EKG screen actual strips off the EKG screen (dynamic (dynamic

interpretation) interpretation)

What is What is an ectopic foci?an ectopic foci?

Ectopic FociEctopic Foci

Any foci that sends off electrical activity that results in cardiac depolarization that is NOT part of the normal conduction system.

These may or may not produce an actual “pump” of the heart. most ectopic foci beats are “nonsytole”

INSERT ECTOPIC FOCUS PICTURE HERE

What is re-entry?What is re-entry?

A disturbance or abnormality in the A disturbance or abnormality in the conduction pathway. conduction pathway.

This can cause tachyarrhytmias or This can cause tachyarrhytmias or ectopic beats.ectopic beats.

Wolf Parkinson White (WPW) is a type of reentry rhythm, as are some of the supraventricular tachycardia “SVT” family.

Let’s ReviewLet’s Review

Based on simple findings so far,Based on simple findings so far, which of the three pacemaker sites is this which of the three pacemaker sites is this

impulse coming from?impulse coming from?

What is the intrinsic rate of thisWhat is the intrinsic rate of this pacemaker site? pacemaker site?

From the SA node From the SA node rate 60-100 min rate 60-100 min

Which of the three pacemaker sites is this Which of the three pacemaker sites is this

impulse coming from?impulse coming from?

What is the intrinsic rate of this What is the intrinsic rate of this pacemaker site?pacemaker site?

AV node AV node rate 40-60 minrate 40-60 min

Which of the three pacemaker sites is this Which of the three pacemaker sites is this impulse coming from? impulse coming from?

What is it’s intrinsic rate?What is it’s intrinsic rate?

VentriclesVentricles20-40 min20-40 min

Calculate the rate...Calculate the rate...

(6 second strip)(6 second strip)

RateRate

150 150 if counting total QRS complexes in if counting total QRS complexes in

six secondssix seconds

150 150 if using 0.20s line markings (300, 150, etc)if using 0.20s line markings (300, 150, etc)

P-R interval (PRI)P-R interval (PRI)should be between…should be between…

3-5 small squares3-5 small squares 0.12s-0.20s 0.12s-0.20s

QRS complex should be…QRS complex should be…

No greater than 3 small squares No greater than 3 small squares or 0.12s*or 0.12s*

* Some cardiac text books state * Some cardiac text books state

wide QRS is > .10s, however with wide QRS is > .10s, however with the paper we can not be that the paper we can not be that

specific….specific….

End of Review, End of Review, on to...on to...

Rhythms originating Rhythms originating in the atria...in the atria...

Atrial RhythmsAtrial Rhythms

Normal Sinus Rhythm: this is the normal rhythm. Originating in the SA node.

Rhythm - regular Rate - 60 - 100/min“P” waves - Upright before each QRS P-R interval 0.12 - 0.20QRS complex - less than 0.12 seconds “T” wave - one after each

QRS complex

Sinus bradycardia: due to damage of the SA node, or parasympathetic effect of the nervous system, the rate a which the SA node discharges is slowed down...

Rhythm - regular Rate - less than 60/minute“P” waves - Upright before each QRS P-R interval - 0.12-0.20QRS complex - less than 0.12 seconds “T” wave - one after each

QRS complex

Atrial RhythmsAtrial Rhythms

Sinus tachycardia: due to damage of the SA node, or increased sympathetic tone of the nervous system, the rate a which the SA node discharges is increased...

Rhythm - regular Rate - 100-150 min“P” waves - Upright before each QRS P-R interval - 0.12-0.20QRS complex - less than 0.12 seconds “T” wave - one after each

QRS complex

Atrial RhythmsAtrial Rhythms

Atrial tachycardia: due to an ectopic foci firingvery fast. So fast you may not see a “P” wave

Rhythm - regular Rate - 150 -260 min“P” waves - Upright before each QRS P-R interval - 0.12-0.20QRS complex - less than 0.12 seconds “T” wave - one after each

QRS complex

Atrial RhythmsAtrial Rhythms

Multifocal Atrial tachycardia: Similar to atrial tach, except, that there has to be three different p wave morphologies

Rhythm – regular or irregular Rate - 150 -260 min“P” waves - Upright before each QRS with

different shapes P-R interval - 0.12s-0.20sQRS complex - less than 0.12 seconds “T” wave - one after each

QRS complex

Atrial RhythmsAtrial Rhythms

Atrial Fibrillation: ectopics in the atria take over by creating their own impulse…Every now and then one of the impulses conducts into the ventricles.

Rhythm – irregularly irregular Rate - 60-100“P” waves - no “P” waves, fibrillatory waves P-R interval - noneQRS complex - less than 0.12 seconds “T” wave - one after each

QRS complex

Atrial RhythmsAtrial Rhythms

Atrial flutter: due to re-entry in the atriumMost A-flutter are consistent with conduction, Below is an example of 3 / 1 conduction.

Rhythm – usually regularly / irrregular Rate - can vary (70) min“P” waves - Sawtooth (flutter) waves P-R interval - no ‘P’ wavesQRS complex - less than 0.12 seconds “T” wave - one after each

QRS complex

Atrial RhythmsAtrial Rhythms

Supraventricular Tachycardia(s)Supraventricular Tachycardia(s)(SVT)(SVT)

•Sinus TachycardiaSinus Tachycardia

•Atrial Flutter Atrial Flutter •Flutter over 100 per minuteFlutter over 100 per minute

•Atrial Fibrillation Atrial Fibrillation •over 100 per minute, also referred to as rapid ventricular response (RVR)over 100 per minute, also referred to as rapid ventricular response (RVR)

•Atrial TachycardiaAtrial Tachycardia

Rhythms originating in Rhythms originating in AV nodeAV node

Dysrhythmias in the Dysrhythmias in the AV nodeAV node

Junctional Rhythm: If damage to SA node, the AV node will take over. The AV node fires at a rate of 40-60

Rhythm - regular Rate - 40-60 min“P” waves - none/inverted before the QRS complexP-R interval - none or shortenedQRS complex - less than 0.12 seconds “T” wave - one after each

QRS complexif rate is 60-100 (accelerated junctional rhythm)(over 100 Junctional Tachycardia)

Dysrhythmias in the Dysrhythmias in the AV nodeAV node

Junctional Rhythm: If damage to SA node, the AV node will take over. The AV node fires at a rate of 40-60

Rhythm - regular Rate - 40-60 min“P” waves - none/inverted before the QRS complexP-R interval - none or shortenedQRS complex - less than 0.12 seconds “T” wave - one after each

QRS complexif rate is 60-100 (accelerated junctional rhythm)(over 100 Junctional Tachycardia)

AV nodal blocksAV nodal blocks

Rhythm - regular Rate - 60-100“P” waves - Normal P-R interval - > 0.2 secondQRS complex - Normal “T” wave - one after each

QRS complex

Blocks in the Blocks in the AV nodeAV node

1st degree block: Due to a delay in the AV node, there is a delay in the P-R interval. This delay is consistent with each impulse

Delay

2nd degree block Type 1: The block at the AV node becomes progressively longer until a beat is not allowed through. And then the pattern repeats itself.(rhythm also called WenkebachWenkebach…)

Rhythm - Irregular Rate - 60 - 100 min“P” waves - NormalP-R interval - becomes progressively longer until a beat is skipped.QRS complex - Normal “T” wave - one after each

QRS complex

Blocks in the Blocks in the AV nodeAV node Delay

2nd degree block Type II: The AV node has become further damaged and not all impulses are conducted through into the ventricles.

Blocks in the Blocks in the AV nodeAV node

Rhythm - Irregular Rate - A-norm V-slow“P” waves - not all “P” waves are connected to a QRS complexP-R interval - only some of the beats are transmitted to the ventricles.QRS complex - Normal “T” wave - one after each

QRS complex

SA impulses blocked at AV node

SA impulses that made it through

2nd degree type 1

2nd degree type II

What is the key difference between

a 2nd degree type I (wenkebach) & 2nd degree type II?

• Second Degree type one…..P wave seems to be Second Degree type one…..P wave seems to be getting further away from QRS, then a QRS getting further away from QRS, then a QRS complex is missed (not conducted). complex is missed (not conducted). • if measured out it is actually the QRS getting further from P wave…..if measured out it is actually the QRS getting further from P wave…..

• Second Degree type two…..When present the P Second Degree type two…..When present the P wave and QRS appear normal, but there are wave and QRS appear normal, but there are missed (non conducted) beats with no lengthening missed (non conducted) beats with no lengthening of PRI.of PRI.

3rd degree block: No impulse is transmitted into the ventricles therefore, the atrium and ventricles fire independently of each other.

Rhythm -both atrium and ventricles are regular but independent Rate - Atrium 60-100/ Ventricles 20-40“P” waves - NormalP-R interval - None as no relationship between the atrium and ventriclesQRS complex - Wide, ventricles “T” wave: Normal/upright

Complete block

Blocks in the Blocks in the AV nodeAV node

• Be mindful when reviewing third degree Be mindful when reviewing third degree blocks. There will be times when the P blocks. There will be times when the P wave and QRS look like they match wave and QRS look like they match up……up……

• If the SA is depolarizing at 60, and the If the SA is depolarizing at 60, and the ventricles depolarizing at 30, it may ventricles depolarizing at 30, it may appear that these line up every few cycles.appear that these line up every few cycles.

Blocks in the Blocks in the AV nodeAV node

3rd degree block3rd degree block

2nd degree type 12nd degree type 1

2nd degree type II2nd degree type II

Rhythms from the ventriclesRhythms from the ventricles

Ventricular Tachycardia: irritable focus in the ventricles

Rhythm -regularRate - 100-250“P” waves - usually not presentP-R interval - no “P’ waves, therefore no P-R intervalQRS complex - Wide usually greater than 0.20 seconds“T” wave: not seen, may be hidden in the other rhythms

Dysrhythmias in the Dysrhythmias in the VentriclesVentricles

Ventricular Fibrillation: ectopic firing in the ventricles because the AV node and SA node are not creating electrical impulses.

Rhythm -no organized rhythmRate can’t be determined“P” waves - noneP-R interval - no “P’ waves, therefore no P-R intervalQRS complex - none“T” wave: no “T” waves

Dysrhythmias in the Dysrhythmias in the VentriclesVentricles

The words Dysrhythmia and Arrhythmia The words Dysrhythmia and Arrhythmia have become interchangeable in ECG have become interchangeable in ECG terminology today, however…..terminology today, however…..

There is one true arrhythmia……There is one true arrhythmia……

Asystole: absolutely no electrical stimulus, therefore no contractions of the heart and nothing seen on the EKG strip….

Rhythm noneRate - no rate“P” waves - not presentP-R interval - no “P’ waves, therefore no P-R intervalQRS complex - no QRS“T” wave: none

The one true Arrhythmia The one true Arrhythmia

And now the “F.L.B.’s”And now the “F.L.B.’s”(funny little beats)(funny little beats)

P.A.C.’sP.A.C.’s

Premature Atrial Contractions (PAC’s): Due to damage or irritation the foci in the atrium occasionally fire producing a premature contraction.

Rhythm - Underlying is regular Rate - depends on underlying“P” waves - normal in underlying, the PAC “P” waves look differentP-R interval - normal for the underlying, different for the “P” wavesQRS complex - less than 0.12 seconds “T” wave - one after each

QRS complex

Rhythm - underlying regular Rate - depends on underlying“P” waves - none or inverted P-R interval - 0.12-0.16QRS complex - less than 0.12 seconds “T” wave - one after each

QRS complex

Premature Junctional Contractions (PJC’s): The AV node can be irritated and release extra beats causing premature beats….

P.J.C.’sP.J.C.’s

Premature Ventricular Contractions: ectopic firing in the ventricles can cause premature beats

Rhythm -underlying may be regular or irregularRate - depending on underlying rhythm“P” waves - Normal in the underlying rhythm/the PVC’s do not have a “P” waveP-R interval - Normal in the underlying rhythm, none for PVC’sQRS complex - The underlying rhythm’s QRS is normal/ the PVC’s are wide anddistorted looking“T” wave: Normal and upright/PVC’s may have no T’s

P.V.C.’sP.V.C.’s

Premature Premature Ventricular ContractionsVentricular Contractions

• PVC’s are a troublesome extrasystole PVC’s are a troublesome extrasystole in nomenclature as there are several in nomenclature as there are several points that need to be addressed.points that need to be addressed.• FocusFocus• ““Gemini”Gemini”• Couplets, triplets, etc.Couplets, triplets, etc.

Premature Premature Ventricular ContractionsVentricular Contractions

• Focus: Focus: • Where the extrasystole originates. Where the extrasystole originates.

• We are looking for :We are looking for :

““unifocal” unifocal”

(one focus, all waveforms (one focus, all waveforms are identical) are identical)

“ “Multifocal” Multifocal”

(more than one waveform (more than one waveform shape). shape).

Premature Premature Ventricular ContractionsVentricular Contractions

• Examples of Unifocal PVC’s.Examples of Unifocal PVC’s.The wave PVC’s are identical with others on the The wave PVC’s are identical with others on the

same strip.same strip.

Premature Premature Ventricular ContractionsVentricular Contractions

• Example of Multifocal PVCExample of Multifocal PVCNote the distinct difference in wave Note the distinct difference in wave morphology.morphology.

Premature Premature Ventricular ContractionsVentricular Contractions

• ““Gemini”: how many beats between Gemini”: how many beats between PVC’s.PVC’s.

Bigeminal: every second beat is a PVCBigeminal: every second beat is a PVC

Trigeminal: every third beat is a PVCTrigeminal: every third beat is a PVC

Quadrigeminal: every fourth beat is a Quadrigeminal: every fourth beat is a PVCPVC

Premature Premature Ventricular ContractionsVentricular Contractions

Bigeminal rhythm

Trigeminal Rhythm

SA beats

Premature Premature Ventricular ContractionsVentricular Contractions

Couplet

Triplet

Premature Premature Ventricular ContractionsVentricular Contractions

Multifocal triplet

Depending on the specific textbook a run of four (quadruplet) PVC’s is classed as a “salvo” or a small run of V-Tach.

Pacemaker RhythmPacemaker Rhythm

Pacemaker: the impulse is generated from an outside source.

Rhythm -can be irregular or regular depending on how often the pacemaker firesRate - dependant on the rate of the pacemaker“P” waves - none presentP-R interval - no “P” wavesQRS complex - Normal or wide“T” wave: Normal

PACEMAKERSPACEMAKERS

Pacemaker: the impulse is generated from an outside source.

Rhythm -can be irregular or regular depending on how often the pacemaker firesRate - dependant on the rate of the pacemaker“P” waves - none presentP-R interval - no “P” wavesQRS complex - Normal or wide “T” wave: Normal

Pacemaker RhythmPacemaker Rhythm

ECG interpretationECG interpretation• ECG interpretation is a skill that needs to ECG interpretation is a skill that needs to

be practiced on a regular basis.be practiced on a regular basis.• At the conclusion of this presentation you At the conclusion of this presentation you

should be able to interpret:should be able to interpret:• All SA rhythmsAll SA rhythms• All AV Junctional rhythmsAll AV Junctional rhythms• All AV Nodal blocksAll AV Nodal blocks• All Ventricular rhythmsAll Ventricular rhythms• All Extrasystole beats (PAC, PJC, PVC)All Extrasystole beats (PAC, PJC, PVC)

ECG interpretationECG interpretation• Please review this presentation as Please review this presentation as

required.required.• After you are comfortable with these After you are comfortable with these

rhythms please review the intermediate rhythms please review the intermediate ECG presentation which deals with ECG ECG presentation which deals with ECG in the presence of Acute Myocaridal in the presence of Acute Myocaridal Infarction and other cardiac emergenciesInfarction and other cardiac emergencies..

Suggested ReadingSuggested Reading• Arrhythmia Recognition, the art of Arrhythmia Recognition, the art of

interpretaiton. (ISBN0-7637-1961-7)interpretaiton. (ISBN0-7637-1961-7)• Authors: Thomas Garcia + Geoffrey MillerAuthors: Thomas Garcia + Geoffrey Miller• Jones and Bartlett Pulishers (jbpub.com)Jones and Bartlett Pulishers (jbpub.com)• Also Available on Amazon.caAlso Available on Amazon.ca

• ECG’s made easy (ISBN 0-323-01433-ECG’s made easy (ISBN 0-323-01433-X)X)• Author: Barbara AehlertAuthor: Barbara Aehlert• Mosby PressMosby Press

• Also a good idea to grab a test book Also a good idea to grab a test book for extra practice.for extra practice.

Thank you for Thank you for your kind attentionyour kind attention

Happy Interpreting……Happy Interpreting……