electrocardiogram ppt

ELECTROCARDELECTROCARDIOGRAMIOGRAM

ELECTROCARDIOGRAMELECTROCARDIOGRAM The electrocardiogram (ECG) is a graphic The electrocardiogram (ECG) is a graphic

recording of the electrical potentials recording of the electrical potentials produced by the cardiac tissue.produced by the cardiac tissue. Electrical impulse formation occurs within Electrical impulse formation occurs within

the conduction system of the heart.the conduction system of the heart. Excitation of the muscle fibers throughout the Excitation of the muscle fibers throughout the

myocardium results in cardiac contraction.myocardium results in cardiac contraction. The ECG is recorded by applying The ECG is recorded by applying

electrodes to various locations on the electrodes to various locations on the body surface and connecting them to a body surface and connecting them to a recording apparatus.recording apparatus.

ELECTROCARDIOGRAMELECTROCARDIOGRAM

Clinical Value of the ECGClinical Value of the ECG Atrial and ventricular hypertrophyAtrial and ventricular hypertrophy Myocardial ischemia and infarctionMyocardial ischemia and infarction PericarditisPericarditis Systemic diseases that affect the heartSystemic diseases that affect the heart Determination of the effect of cardiac drugsDetermination of the effect of cardiac drugs Disturbances in electrolyte balanceDisturbances in electrolyte balance Evaluation of function of cardiac Evaluation of function of cardiac

pacemakerspacemakers

ELECTROCARDIOGRAMELECTROCARDIOGRAM

Value of ECG in the following Value of ECG in the following clinical conditionsclinical conditions Prediction of sudden cardiac deathPrediction of sudden cardiac death Prediction of ischemic pre-conditioningPrediction of ischemic pre-conditioning Prediction of adverse states in AMI, Prediction of adverse states in AMI,

post-MI and silent ischemia casespost-MI and silent ischemia cases Progression/regression of LV massProgression/regression of LV mass

RECORDING AND RECORDING AND MONITORING AN ECGMONITORING AN ECG

Lead ConfigurationsLead Configurations Bipolar LeadsBipolar Leads

Two electrodes placed at 2 different sitesTwo electrodes placed at 2 different sites Register the difference in potential between Register the difference in potential between

these 2 leadsthese 2 leads Unipolar leadsUnipolar leads

Measure the absolute electrical potential at Measure the absolute electrical potential at one siteone site

Requires a reference siteRequires a reference site Reference site formed by the limb leadsReference site formed by the limb leads

12 LEAD ECG12 LEAD ECG

Chest LeadsChest Leads Limb LeadsLimb Leads

RARA RedRed Right arm Right arm

LALA YellowYellow Left armLeft arm

LLLL GreenGreen Left legLeft leg

RLRL BlackBlack Right legRight leg

VV11 Red Red 4 4thth ICS RPSBICS RPSB

VV22 YellowYellow 44thth ICS LPSB ICS LPSB

VV33 GreenGreen Midway between Midway between

VV22 and V and V44

VV44 BrownBrown 55thth ICS LMCL ICS LMCL

VV55 BlackBlack LAAL Lateral & LAAL Lateral &

horizontal to Vhorizontal to V44

VV66 VioletViolet LMAL Lateral & LMAL Lateral &

horizontal to Vhorizontal to V44

ELECTROPHYSIOLOGY OF ELECTROPHYSIOLOGY OF THE HEARTTHE HEART

Four Electrophysiologic Events Four Electrophysiologic Events Involved in the Genesis of the ECGInvolved in the Genesis of the ECG Impulse formationImpulse formation Transmission of the impulseTransmission of the impulse DepolarizationDepolarization Repolarization Repolarization

LAYERS OF THE HEART LAYERS OF THE HEART WALLWALL

EpicardiumEpicardium Coronary arteries are Coronary arteries are

found in this layerfound in this layer MyocardiumMyocardium

Responsible for Responsible for contraction of the contraction of the heartheart

EndocardiumEndocardium Lines the inside of the Lines the inside of the

myocardiummyocardium Covers the heart Covers the heart

valvesvalves

CONDUCTION SYSTEM OF CONDUCTION SYSTEM OF THE HEARTTHE HEART

SA NodeSA Node

Atrial MuscleAtrial MuscleAV NodeAV Node

Bundle of HisBundle of His

Bundle BranchesBundle Branches

Purkinje FibersPurkinje Fibers

Ventricular MuscleVentricular Muscle

TERMINOLOGYTERMINOLOGY WaveformWaveform

Movement away from the Movement away from the baseline in either a positive or baseline in either a positive or negative directionnegative direction

SegmentSegment A line between wave formsA line between wave forms

IntervalInterval A waveform and a segmentA waveform and a segment

ComplexComplex Consists of several waveformsConsists of several waveforms

ECG PAPERECG PAPER

ELECTROGRAMELECTROGRAM

Upward deflectionUpward deflection

Downward deflectionDownward deflection

Diphasic deflectionDiphasic deflection

- +

- +

- +

THE NORMAL THE NORMAL ELECTROCARDIOGRAMELECTROCARDIOGRAM

P waveP wave Generated by activation of the atriaGenerated by activation of the atria

PR segmentPR segment Represents the duration of atrioventricular Represents the duration of atrioventricular

(AV) conduction(AV) conduction QRS complexQRS complex

Produced by activation of both ventriclesProduced by activation of both ventricles ST-T waveST-T wave

Reflects ventricular recoveryReflects ventricular recovery

STANDARD 12 LEAD ECGSTANDARD 12 LEAD ECG The P waveThe P wave

Atrial activationAtrial activation Height Height << 0.2 mV (2 mm) 0.2 mV (2 mm) Duration < 0.12 secDuration < 0.12 sec

STANDARD 12 LEAD ECGSTANDARD 12 LEAD ECG

P-R IntervalP-R Interval Intraatrial, internodal, His purkinje Intraatrial, internodal, His purkinje

conductionconduction Duration 0.12 to 0.20 or 0.22 secDuration 0.12 to 0.20 or 0.22 sec

STANDARD 12 LEAD ECGSTANDARD 12 LEAD ECG The QRS ComplexThe QRS Complex

Ventricular activationVentricular activation Duration of 100 msecDuration of 100 msec

STANDARD 12 LEAD ECGSTANDARD 12 LEAD ECG The ST-segmentThe ST-segment

Phase 2 of transmembrane potentialPhase 2 of transmembrane potential Isoelectric in normal subjectsIsoelectric in normal subjects

STANDARD 12 LEAD ECGSTANDARD 12 LEAD ECG The T waveThe T wave

Upright after the age of 16Upright after the age of 16 JuvenileJuvenile T wave T wave

STANDARD 12 LEAD ECGSTANDARD 12 LEAD ECG The U waveThe U wave

Surface reflection of negative after Surface reflection of negative after potentialpotential

Repolarization of Purkinje fibersRepolarization of Purkinje fibers Ventricular relaxationVentricular relaxation

STANDARD 12 LEAD ECGSTANDARD 12 LEAD ECG The QT IntervalThe QT Interval

From beginning of QRS to end of T From beginning of QRS to end of T wavewave

Reflects the duration of Reflects the duration of depolarization and repolarizationdepolarization and repolarization

Bezett: Q-Tc Interval = Q-T/ R-RBezett: Q-Tc Interval = Q-T/ R-R

ANALYZING A RHYTHM ANALYZING A RHYTHM STRIPSTRIP

RateRate RhythmRhythm AxisAxis P waveP wave PR IntervalPR Interval QRS ComplexQRS Complex T waveT wave Q-T IntervalQ-T Interval


What is the rate?What is the rate? To determine the ventricular To determine the ventricular

rate,measure the distance between 2 rate,measure the distance between 2 consecutive R-waves (R-R interval)consecutive R-waves (R-R interval)

To determine the atrial rate, measure To determine the atrial rate, measure the distance between 2 consecutive P-the distance between 2 consecutive P-waves (P-P interval)waves (P-P interval)

What Is The Rate?What Is The Rate? Ventricular RateVentricular Rate

Small squares (R-R Interval) / 1500Small squares (R-R Interval) / 1500 Big squares (R-R Interval) / 300Big squares (R-R Interval) / 300


Is the rhythm regular or irregular?Is the rhythm regular or irregular? To determine if the ventricular rhythm is To determine if the ventricular rhythm is

regular or irregular, measure the distance regular or irregular, measure the distance between 2 consecutive R-R intervals and between 2 consecutive R-R intervals and compare that distance with the other R-r compare that distance with the other R-r intervals.intervals.

For atrial rhythm, measure the distance For atrial rhythm, measure the distance between 2 consecutive P-P intervals.between 2 consecutive P-P intervals.

Generally, a variation of up to 0.12 seconds (3 Generally, a variation of up to 0.12 seconds (3 small boxes) is acceptable. The slower the small boxes) is acceptable. The slower the heart rate, the more acceptable the variation.heart rate, the more acceptable the variation.

electrocardiogram ppt

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