final intro to cardiac pdf

8/6/2019 Final Intro to Cardiac PDF

1/46

BASICS OF EKG


2/46

Cardiac Conduction Cycle

Anatomy and Physiology

How does the Electrical movement manifest on graph paper

Cardiac Cycle Family

Anatomy of a Normal Sinus Rhythm

Graphic Representation of Cardiac Cycle

Know that there are many different types of arrythmias

The different locations arrythmias stem from

Typical arrhythmias seen

Arrythmias

Patient Preperation Lead Placement

EKG Procedure

Typical Cardiac Medication

Cardiac Labs


3/46

Anatomy and Physiology of Cardiac

Cycle


4/46

Anatomy of the Conduction Cycle

What Parts of the Heart

Make Up The Conduction

System

SA NodeAV nodes

Bundle of HIS

Right Bundle Branch

Left Bundle BranchPurkinje Fibers


5/46

The PQRST of Normal Sinus

Rhythm


6/46

The Conduction Cycle

Press arrow

to play

video


7/46

P WAVE-

PR INTERVAL

P WAVE represents atrialdepolarization(electrical

stimulation) and when it

occurs on the EKG or strip

we know that the atrial

cells have received thestimulus from the SA

Node.

PR INTERVAL: The PRinterval measures thetime it takes the impulse

to travel from the atria to

the ventricles.


8/46

PR SEGMENT

In between the P wave and

the beginning of the QRS

complex you will notice a

flat line. That is when the

impulse enters the AV Node,

where it is held until the

ventricles are ready to

receive it. This is a normal

delay in the travel of the

impulse through the heart.

Because its in aholding

pattern, there is no electrical

stimulation which causes

the line to return to the flat

isoelectric line.


9/46

QRS COMPLEX

QRS complex

represents

ventricular

depolarization and

when it occurs weknow the ventricular

cells have received

the stimulus.

It is measuring the

time it takes the

impulse to travel

through the

ventricles.


10/46

ST SEGMENT

T WAVE

ST SEGMENT: an isolectric

line following the QRS

complex. It is telling us

that the ventricles are

repolarizing.

T WAVE: last wave formduring a NSR. When this

occurs we know that the

ventricles have recovered

and are ready for the next

impulse to occur.


11/46

The Cardiac Cycle Family

(2 full QRST complexes on the graph)

The cardiac cyclefamily includes

the P wave, QRSand ST segments

and the T Wave

When the cardiaccycle is normal allof the waveforms(PQRST) will bepresent on the

rhythm strip ofEKG

All of these waveforms

can be positive (abovethe isoelectric line),negative (below theisoelectric time) or

biphasic (waveforms

with componentsabove and below the

isoelectric line)


12/46

RECOGNIZING NORMAL SINUSRHYTHM ON AN EKG STRIP.


13/46

The EKG paper is divided into small squares and large squares. Ea ch large square contais 25

small quares.

On the horizontal line, one small square represents .04 seconds and one large squarerepresents .20 seconds in time

On the vertical line one small square represents 1 mm and one large square reoresebts 5mm

in voltage.

30 large squares equals 6 seconds in time. When calculating time for the different waves,

segments and complexes you count the amount of small squares and multiply by o.4

When calculating the heart rate., you are also counting the ventricular rate: count thenumber of squares inbetween the two spikes of the QRS complex..

30 large squares equal 6 second strips. You can calculate the HR by counting how many QRS

complexes there are in a six second time frame and multiplying by ten.


14/46

Normal Sinus Rhytm Requirements

Ventricular Rate: 60-100bpm

Ventricular Rhythm: RegularVentricular rhythm is determined by measuring the R-R

interval. The R-R interval is the dcistance between 2 QRS

complexesPWAVES: P waves should be present, a P wave for ever QRS

and the configuration normal for eh lead. P waves shouldbe upright in Lead II and the can be upright, biphasic orinverted in Lead V1 (rhythm strips on telemetry floors and

the bottom of the 12 lead ekg, are lead II)Atrial Rate : 60- 100Count how many boxes inbetween the p waves. Or , on a second

strip count how many p waves and multiply by 10.


15/46

Normal Sinus Rhytm Requirements

Atrial Rhythm is determined by measuring the P-P interval .They should be the same distance between on eachmeasured. A variation of 0.12 seconds (3 small squares)can occur and the rhythm is considered regular.

PR Interval: The PR interval measures the time it takes theimpulse to travel from the atria to the ventricles.

QRS: The QRS duration measures the time it takes theimpulse to travel through the ventricles.

Twaves should all have the same configuration. Twaves

have a wealth of information in them and is important tostudy, they are almost the most unstable component of anEKG. A different T wave configuration does not alwaysmean something is going on.


16/46

NSR BY THE NUMBERS


17/46

Abnormalities That Can Be Diagnosed

with EKG : Hyperkalemia,

some drugs,

certain genetic abnormalities

Shortened QT interval

Hypokalemia

some drugs

certain gentic abnormalities

Prolonged QT interval:

: Coronary Ischemia,

hypokalemia,Left Ventricular hypertropy

, Digoxin effect, s

some drugs.

Flattened or Inverted T waves

1st sign of acute MI, where T waves become more prominent, symmetricaland pointedHyperacute T Waves:

Low Magnesium\PVCs present:

HyperkalemiaPeaked Twaves, widened

QRS complex, Depressed ST

HypokalemiaFlattened T waves, Prominent

U waves


18/46


19/46

Sinus Bradycardia

A heart rate less than 60 beats per minute (BPM). Thisin a healthy athletic person may be 'normal', but othercauses may be due to increased vagal tone from drugabuse, hypoglycaemia and brain injury with increaseintracranial pressure (ICP) as examples

Looking at the ECG you'll see that:

Rhythm - Regular Rate - less than 60 beats per minuteQRS Duration - Normal P Wave - Visible before eachQRS complex P-R Interval - Normal Usually benign andoften caused by patients on beta blockers


20/46

SINUS TACHYCARDIA

An excessive heart rate above 100 beats per minute (BPM)which originates from the SA node. Causes include stress,fright, illness and exercise. Not usually a surprise if it istriggered in response to regulatory changes e.g. shock. Butif their is no apparent trigger then medications may berequired to suppress the rhythm


Rhythm - Regular Rate - More than 100 beats per minute

QRS Duration - Normal P Wave - Visible before each QRScomplex P-R Interval - Normal The impulse generating theheart beats are normal, but they are occurring at a fasterpace than normal. Seen during exerc


21/46

Supraventricular Tachycardia (SVT) Abnormal

A narrow complex tachycardia or atrial tachycardia which originates in the'atria' but is not under direct control from the SA node. SVT can occur in allage groups


Rhythm - Regular

Rate - 140-220 beats per minute

QRS Duration - Usually normal

P Wave - Often buried in preceding T wave

P-R Interval - Depends on site of supraventricular pacemaker

Impulses stimulating the heart are not being generated by the sinus node,but instead are coming from a collection of tissue around and involvingthe atrioventricular (AV) node


22/46

Atrial Fibrillation

Many sites within the atria are generating their own electrical impulses, leading to irregular conduction

of impulses to the ventricles that generate the heartbeat. This irregular rhythm can be felt whenpalpating a pulse


Rhythm - Irregularly irregular Rate - usually 100-160 beats per minute but slower if on medicationQRS Duration - Usually normal P Wave - Not distinguishable as the atria are firing off all over P-RInterval - Not measurable The atria fire electrical impulses in an irregular fashion causing irregularheart rhythm Fibrillation

Many sites within the atria are generating their own electrical impulses, leading to irregularconduction of impulses to the ventricles that generate the heartbeat. This irregular rhythm can befelt when palpating a pulse


Rhythm - Irregularly irregular Rate - usually 100-160 beats per minute but slower if on medicationQRS Duration - Usually normal P Wave - Not distinguishable as the atria are firing off all over P-RInterval - Not measurable The atria fire electrical impulses in an irregular fashion causing irregularheart rhythm


23/46

Atrial Flutter Looking at the ECG you'll see that:

Rhythm - Regular Rate - Around 110 beats per

minute QRS Duration - Usually normal P Wave -Replaced with multiple F (flutter) waves, usuallyat a ratio of 2:1 (2F - 1QRS) but sometimes 3:1 PWave rate - 300 beats per minute P-R Interval -

Not measurable As with SVT the abnormal tissuegenerating the rapid heart rate is also in the atria,however, the atrioventricular node is not involvedin this case.


24/46

1st Degree AV Block

1st Degree AV block is caused by a conduction delaythrough the AV node but all electrical signals reach theventricles. This rarely causes any problems by itself andoften trained athletes can be seen to have it. Thenormal P-R interval is between 0.12s to 0.20s in length,or 3-5 small squares on the ECG.


Rhythm - Regular Rate - Normal QRS Duration - NormalP Wave - Ratio 1:1 P Wave rate - Normal P-R Interval -Prolonged (>5 small squares)


25/46

2nd Degree Block Type 1 (Wenckebach)

Another condition whereby a conduction block ofsome, but not all atrial beats getting through to theventricles. There is progressive lengthening of the PR

interval and then failure of conduction of an atrial beat,this is seen by a dropped QRS complex.


Rhythm - Regularly irregular Rate - Normal or Slow QRSDuration - Normal P Wave - Ratio 1:1 for 2,3 or 4 cyclesthen 1:0. P Wave rate - Normal but faster than QRS rateP-R Interval - Progressive lengthening of P-R intervaluntil a QRS complex is dropped


26/46

2nd Degree Block Type 2

When electrical excitation sometimes fails to pass throughthe A-V node or bundle of His, this intermittent occuranceis said to be called second degree heart block. Electricalconduction usually has a constant P-R interval, in the caseof type 2 block atrial contractions are not regularlyfollowed by ventricular contraction


Rhythm - Regular Rate - Normal or Slow QRS Duration -

Prolonged P Wave - Ratio 2:1, 3:1 P Wave rate - Normal butfaster than QRS rate P-R Interval - Normal or prolonged butconstant


27/46

3rd Degree Block

3rd degree block or complete heart block occurs whenatrial contractions are 'normal' but no electrical conductionis conveyed to the ventricles. The ventricles then generatetheir own signal through an 'escape mechanism' from afocus somewhere within the ventricle. The ventricularescape beats are usually 'slow'


Rhythm - Regular Rate - Slow QRS Duration - Prolonged P

Wave - Unrelated P Wave rate - Normal but faster than QRSrate P-R Interval - Variation Complete AV block. No atrialimpulses pass through the atrioventricular node and theventricles generate their own rhythm


28/46

Bundle Branch Block

Abnormal conduction through the bundle branches willcause a depolarization delay through the ventricularmuscle, this delay shows as a widening of the QRS complex.Right Bundle Branch Block (RBBB) indicates problems in theright side of the heart. Whereas Left Bundle Branch Block(LBBB) is an indication of heart disease. If LBBB is presentthen further interpretation of the ECG cannot be carriedout.


Rhythm - Regular Rate - Normal QRS Duration - Prolonged PWave - Ratio 1:1 P Wave rate - Normal and same as QRSrate P-R Interval - Normal


29/46

Premature Ventricular Complexes Due to a part of the heart depolarizing earlier than it

should


Rhythm - Regular Rate - Normal QRS Duration - Normal PWave - Ratio 1:1 P Wave rate - Normal and same as QRSrate P-R Interval - Normal Also you'll see 2 oddwaveforms, these are the ventricles depolarisingprematurely in response to a signal within the

ventricles.(Above - unifocal PVC's as they look alike ifthey differed in appearance they would be calledmultifocal PVC's, as below)


30/46

Junctional Rhythms Looking at the ECG you'll see that:

Rhythm - Regular Rate - 40-60 Beats per

minute QRS Duration - Normal P Wave - Ratio1:1 if visible. Inverted in lead II P Wave rate -

Same as QRS rate P-R Interval - Variable Below

- Accelerated Junctional Rhythm


31/46

Ventricular Tachycardia (VT) Abnormal


Rhythm - Regular Rate - 180-190 Beats per

minute QRS Duration - Prolonged P Wave - Notseen Results from abnormal tissues in theventricles generating a rapid and irregular heartrhythm. Poor cardiac output is usually associated

with this rhythm thus causing the pt to go intocardiac arrest. Shock this rhythm if the patient isunconscious and without a pulse


32/46

Ventricular Fibrillation (VF) Abnormal

Disorganised electrical signals cause the ventricles toquiver instead of contract in a rhythmic fashion. Apatient will be unconscious as blood is not pumped to

the brain. Immediate treatment by defibrillation isindicated. This condition may occur during or after amyocardial infarct.


Rhythm - Irregular Rate - 300+, disorganised QRSDuration - Not recognisable P Wave - Not seen Thispatient needs to be defibrillated!! QUICKLY


33/46

Asystole - Abnormal


Rhythm - Flat Rate - 0 Beats per minute QRS

Duration - None P Wave - None

Carry out CPR!!


34/46

Myocardial Infarct (MI)


Rhythm - Regular Rate - 80 Beats per minute

QRS Duration - Normal P Wave - Normal S-T

Element does not go isoelectric which

indicates infarction


35/46

LABORATORY TESTS

CMP

Look for electrolyte imbalances.

Particularly look for K+

Precath look at renal functioning due to dye.

Magnesium level

CBCComplete blood count,

Focus on hemoglobin and hematocrit

BNP

High levels are an indicator for congestive heart failure

PT/INR

especially if patient is on anticoagulation therapy


36/46

SCREENING CARDIAC PANEL

TROPONIN

High specificity for myocardial cell injurty, cardiac troponin and

cardiac troponin1 helpful in evaluation of patients with chest

pain

More specific for cardiac injury than CPK-MB

Elevation sooner and remain elevated longer than CPK-MB

Allows longer time for Dx and thrombolytic tx of MI.

Used for differentiating cardiac from non cardiac chest pain

Evaluation of patients with unstable angina

Estimate the size of the MI

Detect preop MI


37/46

SCREENING CARDIAC PANEL

CPK-MB ( creatine phosphokinase)

Specific for myocardial cells

Levels rise three to six hours after damage

If damage is not persistent the levels peak at 18

hours post damage

Returns to normal after two to three days

Cardiac panels are usually done in serial draws.Usually q 8hrs, or q4/12/24hrs. After admit.


38/46

DIAGNOSTIC TESTS

EKG ECHOCARDIOGRAM

STRESS ECHO

TILT TABLE TEST

CARDIAC CATHERIZATION

ELECTROPHYSIOLOGY TEST

CT HEART SCAN

MYOCARDIAL BIOPSY

HEART MRI

PERICARDIOCENTESIS


39/46

ECG/EKG PROCEDURE

ECG Basics The electrocardiogram (ECG) is a diagnostic tool that measures and records the electrical activity of

the heart in detail. Being able to interpretate these details allows diagnosis of a wide range of heartproblems.

ECG Electrodes

Skin Preparation:

Clean with an alcohol wipe if necessary. If the patients are very hairy shave the electrode areas.

ECG standard leads

There are three of these leads, I, II and III.Lead I: is between the right arm and left arm electrodes, the left arm being positive.Lead II: is between the right arm and left leg electrodes, the left leg being positive.Lead III: is between the left arm and left leg electrodes, the left leg again being positive.

Chest Electrode PlacementV1: Fourth intercostal space to the right of the sternum.V2: Fourth intercostal space to the Left of the sternum.V3: Directly between leads V2 and V4.

V4: Fifth intercostal space at midclavicular line.V5: Level with V4 at left anterior axillary line.V6: Level with V5 at left midaxillary line. (Directly under the midpoint of the armpit)


40/46

LEAD PLACEMENT ILLUSTRATIONS


41/46

A little More Info about EKG

Chest LeadsV1 & V2

V3 & V4

V5 & V6

ViewRight Ventricle

Septum/Lateral Left Ventricle

Anterior/Lateral Left Ventricle

ECG Leads The ECG records the electrical activity that results when the heart m uscle cells in the atria and ventricles contract.

Atrial contractions show up as the P wave.

Ventricular contractions show as a series known as the QRS complex.The third and last common wave in an ECG is the T wave. This is the electrical activity produced

when the ventricles are recharging for the next contraction (repolarizing).

Interestingly, the letters P, Q, R, S, and T are not abbreviations for any actual words but were

chosen many years ago for their position in the middle of the alphabet.

The electrical activity results in P, QRS, and T waves that are of different sizes and shapes. When

viewed from different leads, these waves can show a wide range of abnormalities of both theelectrical conduction system and the muscle tissue of the hearts 4 pumping chambers.

- Views of the Heart


42/46


43/46


44/46


45/46


46/46

Copywrite EGM 2011

final intro to cardiac pdf

Documents