EKG Interpretation

ECG Interpretation ECG Interpretation BasicsBasics

Robert Catlow RN, BSN, CNORRobert Catlow RN, BSN, CNORJeanette Hester MSN, RNJeanette Hester MSN, RN

January 2009January 2009

ObjectivesObjectives

Define cardiac outputDefine cardiac outputIdentify anatomy of the heart & its conduction systemIdentify anatomy of the heart & its conduction systemUnderstand common ECG terminologyUnderstand common ECG terminologyRelate ECG waveforms to mechanical function of the heartRelate ECG waveforms to mechanical function of the heartDemonstrate correct lead placement for telemetryDemonstrate correct lead placement for telemetryDemonstrate ECG Interpretation SkillsDemonstrate ECG Interpretation Skills

Atrial arrhythmiasAtrial arrhythmiasJunctional arrhythmiasJunctional arrhythmiasVentricular arrhythmiasVentricular arrhythmiasConduction block arrhythmiasConduction block arrhythmias

Review/interpret rhythm stripsReview/interpret rhythm strips

Cardiac OutputCardiac Output

Cardiac Output (CO) = Heart Rate (HR) X Stroke Cardiac Output (CO) = Heart Rate (HR) X Stroke Volume (SV)Volume (SV)HR = measurement of ventricular impulses, per min. HR = measurement of ventricular impulses, per min. Normal HR = 60Normal HR = 60--100bpm100bpmSV = amount of blood pumped by each ventricular SV = amount of blood pumped by each ventricular contraction, in ml. Normal SV = 60contraction, in ml. Normal SV = 60--80 ml80 mlCO = amount of blood pumped by each ventricle, in CO = amount of blood pumped by each ventricle, in liters/minute Normal CO = 4liters/minute Normal CO = 4--8 l/min8 l/min

Electrophysiology Electrophysiology of the Heartof the Heart

Electrophysiology:Electrophysiology:Automaticity: ability to start an impulseAutomaticity: ability to start an impulseConductivity: ability to transmit impulseConductivity: ability to transmit impulseContractility: contract or squeeze (muscle)Contractility: contract or squeeze (muscle)Rhythmicity: keep impulse/cycle regularRhythmicity: keep impulse/cycle regular

All the above are dependent upon electrolyte All the above are dependent upon electrolyte balance (K, Na, Mg, etc.), nutrients, oxygen balance (K, Na, Mg, etc.), nutrients, oxygen supply, and health of the hearts conductive supply, and health of the hearts conductive systemsystem

Mechanical Physiology of the Mechanical Physiology of the HeartHeart

Four chambers, Right Atria, Four chambers, Right Atria, Right Ventricle, Left Atria, Left Right Ventricle, Left Atria, Left VentricleVentricleFour valves = tricuspid (R), Four valves = tricuspid (R), pulmonic, mitral (L), aorticpulmonic, mitral (L), aorticPump = three tissue layers; Pump = three tissue layers; epicardium, myocaridum, and epicardium, myocaridum, and endocardium rhythmically endocardium rhythmically moving blood in single moving blood in single directiondirectionBlood = necessary purpose Blood = necessary purpose for the pumpfor the pump

Conduction SystemConduction System

1 = SA Node1 = SA Node2 = AV Node2 = AV Node3 = Bundle of HIS3 = Bundle of HIS4 = Left and Right 4 = Left and Right Bundle BranchesBundle Branches5 = Purkinje Fibers5 = Purkinje Fibers

Conduction System & Pacemaker Conduction System & Pacemaker SitesSites

SA Node: Normal pacemaker with normal SA Node: Normal pacemaker with normal adult rate 60adult rate 60--100 impulses/minute100 impulses/minuteAV Node: Secondary pacemaker with AV Node: Secondary pacemaker with inherent rate (adult) 40inherent rate (adult) 40--60 60 impulses/minuteimpulses/minuteVentricular conduction components (Left & Ventricular conduction components (Left & Right Bundle Branches and the Purkinje Right Bundle Branches and the Purkinje Fibers) tertiary pacemaker with inherent Fibers) tertiary pacemaker with inherent rate of 20rate of 20--40 impulses/minute40 impulses/minute

Normal ConductionNormal ConductionSA Node initiates impulseSA Node initiates impulseIntraIntra--atrial pathways carry the atrial pathways carry the impulse to impulse to ……AV Node, slows conduction AV Node, slows conduction ––allowing complete atrial allowing complete atrial contractioncontractionBundle of HIS passes the Bundle of HIS passes the impulse to the ventricular impulse to the ventricular components of components of ……Left & Right Bundle Branches Left & Right Bundle Branches which divide into the which divide into the ……Purkinje FibersPurkinje Fibers

TerminologyTerminologyBaseline Baseline –– isoelectric horizontal lineisoelectric horizontal lineWaves Waves –– deflections from the baseline with defined deflections from the baseline with defined beginning and end pointsbeginning and end pointsSpike Spike –– deflection from the baseline (straight vertical deflection from the baseline (straight vertical line)line)Biphasic Biphasic –– waveform both above and below the baselinewaveform both above and below the baselineSegment Segment –– portion of the baseline between two waves portion of the baseline between two waves (may be elevated or depressed)(may be elevated or depressed)Interval Interval –– defined by start and end points, includes all defined by start and end points, includes all portions of the interval waves and segmentsportions of the interval waves and segmentsDepolarization Depolarization –– impulse formation, conduction & impulse formation, conduction & contractioncontractionRepolarization Repolarization –– relaxation & recoveryrelaxation & recovery

What makes an ECG waveform?What makes an ECG waveform?

When electrical energy travels toward a When electrical energy travels toward a positive electrode a positive (upward) positive electrode a positive (upward) deflection appears on the ECGdeflection appears on the ECGWhen electrical energy travels toward a When electrical energy travels toward a negative electrode a negative (downward) negative electrode a negative (downward) deflection appears on the ECGdeflection appears on the ECGWhen electrical energy travels across the When electrical energy travels across the axis of the positive to negative electrode a axis of the positive to negative electrode a biphasic deflection appears on the ECGbiphasic deflection appears on the ECG

Cardiac Conduction & WaveformsCardiac Conduction & WaveformsP Wave/PR Interval: P Wave/PR Interval: depolarization (contraction) of depolarization (contraction) of the atria. PR interval measured the atria. PR interval measured from start of P to the start of from start of P to the start of QRS complexQRS complexQRS Complex: depolarization QRS Complex: depolarization (contraction) of the ventricles(contraction) of the ventriclesT Wave/ST Segment: T Wave/ST Segment: repolarization (relaxation) of repolarization (relaxation) of the ventricles. ST segment is the ventricles. ST segment is measured from end of S wave measured from end of S wave to start of the T wave to start of the T wave

Electrical and mechanical activity are linked. The P wave represents atrial contraction, the QRS complex ventricular contraction (pulse), and the T wave ventricular recovery.

Lead PlacementLead Placement““Smoke over fire/snow falls on Smoke over fire/snow falls on grassgrass”” ““White is rightWhite is right”” ““Chocolate is Chocolate is close to your heartclose to your heart””

Black over red and white over green, Black over red and white over green, brown in the middle. Set up for these brown in the middle. Set up for these leads are:leads are:

White on right (RA) right White on right (RA) right arm/shoulder/chestarm/shoulder/chestBlack = (LA) left arm/shoulder/chestBlack = (LA) left arm/shoulder/chestGreen = (RL) right leg/flankGreen = (RL) right leg/flankRed = (LL) left leg/flankRed = (LL) left leg/flankBrown = Brown = ““groundinggrounding”” lead, must be either lead, must be either anterior axillary line, 5th intercostal space, anterior axillary line, 5th intercostal space, or lower sternumor lower sternum

Telemetry VS 12Telemetry VS 12--Lead ECGLead ECG

Telemetry usually views Telemetry usually views oneone of the 12 of the 12 standard ECG leadsstandard ECG leads1212--Lead ECG provides 12 Lead ECG provides 12 ““viewsviews”” of the of the hearts electrical activityhearts electrical activity

Limb Leads reveal a vertical view (most Limb Leads reveal a vertical view (most commonly used in telemetry monitoring)commonly used in telemetry monitoring)VV--Leads reveal a horizontal viewLeads reveal a horizontal view

Measuring an ECG StripMeasuring an ECG Strip

Each small box equals Each small box equals 0.04 sec0.04 secEach large box equals Each large box equals 0.20 sec0.20 secIntervals are measured Intervals are measured from start of the wave from start of the wave (leaves baseline) to (leaves baseline) to beginning of next beginning of next waveform (at baseline)waveform (at baseline)

Time is measured on the horizontal axis (width) of the graph paper, electrical energy is measured on the vertical axis (height).

Normal Rhythm IntervalsNormal Rhythm IntervalsNormal Intervals - Adult•PR Interval - 0.12 sec – 0.20 sec

• PR < 0.12 sec (short) = origin closer than normal to Bundle of HIS• PR > 0.20 sec (long) = AV delay (AV Block)

•QRS Interval - 0.06 sec – 0.12 sec• QRS 0.10-0.11 may represent an intraventricular delay• QRS > 0.12 sec may signify a ventricular dysrhythmia

•QT Interval – 0.30 sec – 0.45 sec**•RR Interval indicates heart rate 1.00 sec - 0.60 sec or a heart rate of 60 –100

• RR > 1.00 sec = Bradycardia• RR < 0.60 sec = Tachycardia

•QT Interval and corrected QT Interval measured for advanced interpretation, QTc = QT/ √RR (notify <.30 or >.49

** QT generally should not exceed ½ RR interval at normal rates

Measuring RateMeasuring Rate……The Six Second RuleThe Six Second Rule

Most popular methodMost popular methodECG paper is marked in ECG paper is marked in 3 second intervals3 second intervalsCount # of R waves in 6 Count # of R waves in 6 seconds and multiply by seconds and multiply by 10 = HR10 = HR

Measuring RateMeasuring Rate……The Block/300 The Block/300 RuleRule

Select an R wave on a Select an R wave on a dark linedark lineDivide 300 by number Divide 300 by number of large boxes counted, of large boxes counted, count back # big boxes count back # big boxes 300, 150, 100, 75, 60, 300, 150, 100, 75, 60, 5050…… to next R waveto next R waveNot desirable for Not desirable for counting irregular counting irregular rhythmsrhythms

Normal Sinus Rhythm Normal Sinus Rhythm (NSR/SR)(NSR/SR)

Most common ECG rhythmMost common ECG rhythmNSR/SR rate = 60NSR/SR rate = 60--100 bpm100 bpmRhythm is regularRhythm is regularCardiac cycle has one/normal P wave, QRS complex, and T Cardiac cycle has one/normal P wave, QRS complex, and T wavewaveCalled sinus because it originates from the sinoatrial node Called sinus because it originates from the sinoatrial node (SA Node)(SA Node)ECG diagnosis/rate must always be clinically confirmed with ECG diagnosis/rate must always be clinically confirmed with the presence of a pulse (r/o PEA)the presence of a pulse (r/o PEA)

EctopyEctopy……TerminologyTerminology

Cardiac irritability = increased automatism results in extra Cardiac irritability = increased automatism results in extra heart beats which may have a negative effect on COheart beats which may have a negative effect on COEctopy = an impulse formation located somewhere other Ectopy = an impulse formation located somewhere other than the SA Nodethan the SA Node

Extra (premature) contractions are identified by the location thExtra (premature) contractions are identified by the location they ey come from come from -- the focus (atrium, ventricle, junction)the focus (atrium, ventricle, junction)

Premature contractions = impulses & conduction that occur Premature contractions = impulses & conduction that occur early in the cardiac cycleearly in the cardiac cycleBigeminy Bigeminy –– every other complex is ectopicevery other complex is ectopicTrigeminy Trigeminy –– every third complex is ectopicevery third complex is ectopic

Premature BeatsPremature Beats

There are three types of premature There are three types of premature contractions (PACs, PJCs, PVCs)contractions (PACs, PJCs, PVCs)Ectopy can be identified by evaluating the Ectopy can be identified by evaluating the premature beat for the presence of a p wave premature beat for the presence of a p wave or not and the width of the ventricular or not and the width of the ventricular contractioncontraction

Premature Atrial Contractions Premature Atrial Contractions (PACs)(PACs)

Premature atrial beatPremature atrial beatnormalnormal--sized QRS complexsized QRS complexP wave precedes the premature complexP wave precedes the premature complexnormal looking beats fall earlynormal looking beats fall earlyRhythm is irregular due to the early complexRhythm is irregular due to the early complex

Premature Junctional Premature Junctional Contraction (PJC)Contraction (PJC)

PJCs originate in the junctionPJCs originate in the junctionnormal sized QRS complexnormal sized QRS complexp wave is absent or invertedp wave is absent or invertedrhythm is irregular due to premature rhythm is irregular due to premature complex(es)complex(es)

Premature Ventricular Premature Ventricular Contractions (PVCs)Contractions (PVCs)

premature ventricular beatpremature ventricular beatoriginate in the ventricleoriginate in the ventriclewidewide--bizarre QRS complex (QRS > 0.12 sec)bizarre QRS complex (QRS > 0.12 sec)no visible p wave with premature QRS complexno visible p wave with premature QRS complexPVCs can be unifocal or multifocalPVCs can be unifocal or multifocalWith multiple complexes frequency described by With multiple complexes frequency described by name, i.e. bigeminy, trigeminy name, i.e. bigeminy, trigeminy ……

Premature Ventricular Premature Ventricular Contractions (PVCs)Contractions (PVCs)

multifocal multifocal –– abnormal complexes have multiple abnormal complexes have multiple points of origin (complexes are different from each points of origin (complexes are different from each other)other)

unifocal unifocal –– abnormal complexes have one point of abnormal complexes have one point of origin (complexes are the same)origin (complexes are the same)

S in u s B r a d y c a r d ia ( S B )S in u s B r a d y c a r d ia ( S B )

Caused by depressed automatism in the SA nodeCaused by depressed automatism in the SA nodeClinical causes acute hypoxia, MI, drug intoxications Clinical causes acute hypoxia, MI, drug intoxications (digoxin), and parasympathetic stimulation (digoxin), and parasympathetic stimulation Strip has normal cardiac complex, waves, and Strip has normal cardiac complex, waves, and intervals with a slowed ventricular rateintervals with a slowed ventricular rateSB is either asymptomatic or symptomatic (meaning SB is either asymptomatic or symptomatic (meaning CO may or may not be affected from SB)CO may or may not be affected from SB)Asymptomatic = slow HR and adequate BP/SatsAsymptomatic = slow HR and adequate BP/Sats

Sinus Bradycardia (SB)Sinus Bradycardia (SB)

Symptomatic bradycardia = CO (BP) is significantly Symptomatic bradycardia = CO (BP) is significantly decreased because the ventricular rate is too lowdecreased because the ventricular rate is too lowTreatment for symptomatic bradycardia is aimed at Treatment for symptomatic bradycardia is aimed at increasing HR to improve COincreasing HR to improve CO

ACLS Intervention Sequence ACLS Intervention Sequence for SBfor SB

1. Oxygen1. Oxygen2. Atropine (0.5 mg IV push) may repeat 2. Atropine (0.5 mg IV push) may repeat to a total dose of 3 mg, if ineffective to a total dose of 3 mg, if ineffective ……3. Transcutaneous pacer (TCP)3. Transcutaneous pacer (TCP)4. Epinephrine 2 4. Epinephrine 2 –– 10 mcg/min or 10 mcg/min or ……5. Dopamine 2 5. Dopamine 2 -- 10 mcg/kg/min10 mcg/kg/min6. Prepare for transvenous pacer 6. Prepare for transvenous pacer Field, J.M., Gonzales, L., & Hazinski, M. F. (Eds.). (2006). AdvField, J.M., Gonzales, L., & Hazinski, M. F. (Eds.). (2006). Advanced cardiovascular life support provider anced cardiovascular life support provider manual. Dallas, TX: American Heart Association.manual. Dallas, TX: American Heart Association.

Sinus ArrhythmiaSinus Arrhythmia

Rhythm is benign to the patient Rhythm is benign to the patient Typically associated with respiration due to fluctuations in Typically associated with respiration due to fluctuations in vagal tonevagal toneRarely associated with underlying pathologyRarely associated with underlying pathologyOccurs most commonly in young, healthy patientsOccurs most commonly in young, healthy patientsRate usually increases with inspiration and decreases with Rate usually increases with inspiration and decreases with expirationexpirationTreatment is not usually indicated unless associated with Treatment is not usually indicated unless associated with symptomatic bradycardiasymptomatic bradycardia

Sinus ArrhythmiaSinus ArrhythmiaStrip is noted to have a HR of 45Strip is noted to have a HR of 45--100 (box method), 100 (box method), sinus p wave, normal QRS/conduction, regularlysinus p wave, normal QRS/conduction, regularly--irregular rhythm [use 6irregular rhythm [use 6--sec rule to determine average sec rule to determine average rate]rate]NonNon--respiratory form of sinus arrhythmia is present in respiratory form of sinus arrhythmia is present in diseased hearts. It should not be confused with sinus diseased hearts. It should not be confused with sinus arrestarrest

Sinus Arrest/Sinus PauseSinus Arrest/Sinus PauseOccurs when SA node fails to functionOccurs when SA node fails to functionA complete cardiac complex (more than one A complete cardiac complex (more than one complex may be missed) is absent from the complex may be missed) is absent from the rhythmrhythmCause is usually associated with increased Cause is usually associated with increased vagal tone, myocarditis, MI, and digoxin toxicityvagal tone, myocarditis, MI, and digoxin toxicityUsually present in diseased hearts but can occur Usually present in diseased hearts but can occur in healthy heartsin healthy hearts

Sinus Arrest/Sinus PauseSinus Arrest/Sinus PauseStrip has a normal rate (prior to arrest), p waves, QRS Strip has a normal rate (prior to arrest), p waves, QRS complex, and conduction, rhythm is regular other than the complex, and conduction, rhythm is regular other than the arrest/pausearrest/pauseLength of pause is not related to the sinus intervalLength of pause is not related to the sinus intervalLong pauses can contribute to junctional (escape) beatsLong pauses can contribute to junctional (escape) beatsTreatment is aimed at fixing the underlying cause (i.e. MI, dig Treatment is aimed at fixing the underlying cause (i.e. MI, dig toxicity)toxicity)If symptomatic, than atropine may be indicatedIf symptomatic, than atropine may be indicated

Sinus TachycardiaSinus Tachycardia

Results when automatism of SA node increasesResults when automatism of SA node increasesManifested by increased HR which increases cardiac workload Manifested by increased HR which increases cardiac workload and oxygen demand (can lead to ischemia)and oxygen demand (can lead to ischemia)Causes include increased circulating cathecholamines, CHF, Causes include increased circulating cathecholamines, CHF, hypoxia, PE, fever, pain, stress, agitationhypoxia, PE, fever, pain, stress, agitationST has a HR of 100ST has a HR of 100--160 bpm, sinus P wave (visualized), 160 bpm, sinus P wave (visualized), normal QRS/conductionnormal QRS/conductionTreatment is aimed at identifying and correcting the underlying Treatment is aimed at identifying and correcting the underlying causecause

Atrial Tachycardia Atrial Tachycardia (AT/PAT/SVT)(AT/PAT/SVT)

Frequently called paroxysmal atrial tachycardia (PAT) Frequently called paroxysmal atrial tachycardia (PAT) aka: supraventricular tachycardia (SVT) or paroxysmal aka: supraventricular tachycardia (SVT) or paroxysmal supraventricular tachycardia (PSVT)supraventricular tachycardia (PSVT)Period of very rapid and regular heart beats that begin Period of very rapid and regular heart beats that begin and end abruptlyand end abruptlyResults when automatism in the Results when automatism in the atriaatria is increasedis increasedThe atria form ectopic pacemakers which contribute to The atria form ectopic pacemakers which contribute to overdrive of the sinus rate (SA node)overdrive of the sinus rate (SA node)The result is a cardiac rate of 150The result is a cardiac rate of 150--250 bpm250 bpm

Atrial Tachycardia (AT/PAT/SVT)Atrial Tachycardia (AT/PAT/SVT)

P wave is partially or completely hidden P wave is partially or completely hidden because of the rapid rate, may be flattened, because of the rapid rate, may be flattened, notched, or masked by T wavenotched, or masked by T waveQRS complex is normal sizeQRS complex is normal sizeAT/PAT/SVT manifest as very fast AT/PAT/SVT manifest as very fast tachycardiastachycardias

Atrial Tachycardia Atrial Tachycardia (AT/PAT/SVT)(AT/PAT/SVT)

Ventricular rate is so fast, cardiac output is Ventricular rate is so fast, cardiac output is compromised by decreased ventricular fillingcompromised by decreased ventricular fillingFrequently occurs in stress syndromes and abuse of Frequently occurs in stress syndromes and abuse of caffeine, tobacco, and alcoholcaffeine, tobacco, and alcoholGoals for treatment are aimed at rate control Goals for treatment are aimed at rate control

A C L S I n t e r v e n t io nA C L S I n t e r v e n t io n

Sequence for SVTSequence for SVTVagal maneuversVagal maneuversAdenosine 6mg, 12 mg, then 12 mg rapid Adenosine 6mg, 12 mg, then 12 mg rapid IV push (chase with flush)IV push (chase with flush)ββ blockers & diltiazem used with caution in blockers & diltiazem used with caution in CHF or with pulmonary diseaseCHF or with pulmonary diseaseSynchronized cardioversion if unstable Synchronized cardioversion if unstable SVTSVTField, J.M., Gonzales, L., & Hazinski, M. F. (Eds.). (2006). AdvField, J.M., Gonzales, L., & Hazinski, M. F. (Eds.). (2006). Advanced cardiovascular life support provider manual. anced cardiovascular life support provider manual. Dallas, TX: American Heart Association.Dallas, TX: American Heart Association.

Atrial Flutter Atrial Flutter

A tachydysrhythmia that indicates underlying A tachydysrhythmia that indicates underlying disease processdisease processAtrial rate is usually 250Atrial rate is usually 250--350, rhythm may be regular 350, rhythm may be regular or irregular with varying conduction ratiosor irregular with varying conduction ratiosCharacterized by saw tooth atrial pattern with a Characterized by saw tooth atrial pattern with a normal QRS complexnormal QRS complexMultiple areas (foci) in the atria are competing to Multiple areas (foci) in the atria are competing to drive the heartdrive the heartCommon diseases include valvular heart disease, Common diseases include valvular heart disease, right heart failure, MI, and CADright heart failure, MI, and CAD

Atrial FlutterAtrial FlutterPP-- waves are referred to as Fwaves are referred to as F--waves due to their waves due to their flutter patternflutter patternCommon to refer to ACommon to refer to A--flutter based on the ratio of Fflutter based on the ratio of F--waves to ventricular responses waves to ventricular responses AtrialAtrial--Ventricular ratio may be in 2:1, 3:1, 4:1, etc. Ventricular ratio may be in 2:1, 3:1, 4:1, etc. AA--flutter has a flutter has a regularregular atrial rate, but may be atrial rate, but may be irregularirregular when the conduction ratio changeswhen the conduction ratio changesGoals for treatment are aimed at rhythm conversion Goals for treatment are aimed at rhythm conversion and rate control (digoxin, diltiazem, cardioversion)and rate control (digoxin, diltiazem, cardioversion)

Atrial Fibrillation Atrial Fibrillation (AF/A Fib)(AF/A Fib)

Most common of all dysrhythmiaMost common of all dysrhythmiaCan occur in healthy or diseased heartsCan occur in healthy or diseased heartsIs either acute or chronic (differentiated at 2 weeks)Is either acute or chronic (differentiated at 2 weeks)Common causes include MI, pulmonary embolus, HTN, Common causes include MI, pulmonary embolus, HTN, CAD, and cardiac valvular stenosisCAD, and cardiac valvular stenosisReferred to as Referred to as ““irregularly irregularirregularly irregular””FF--waves have a fibrillating pattern spaced in an irregular waves have a fibrillating pattern spaced in an irregular way, are not shaped consistently, or recognizably separate way, are not shaped consistently, or recognizably separate from each otherfrom each otherQRS complexes are also spaced irregularlyQRS complexes are also spaced irregularly

Atrial Fibrillation Atrial Fibrillation (AF/A Fib)(AF/A Fib)

Ventricular rate can vary between very fast and relatively Ventricular rate can vary between very fast and relatively slow heart ratesslow heart rates

AA--fib w/RVR (Rapid Ventricular Rate)fib w/RVR (Rapid Ventricular Rate)AA--fibfibBradycardia with ABradycardia with A--fibfib

AF is due to lack of synchronized atrial depolarization, AF is due to lack of synchronized atrial depolarization, muscle fibers contract & relax without coordination with other muscle fibers contract & relax without coordination with other fibersfibersAtrial depolarization and mechanical contraction are not Atrial depolarization and mechanical contraction are not organized into an effective patternorganized into an effective patternResult = decreased atrial Result = decreased atrial ““kickkick””

Atrial Fibrillation Atrial Fibrillation (AF/A Fib)(AF/A Fib)

Loss in atrial kick leads to decreased ventricular fillingLoss in atrial kick leads to decreased ventricular fillingDecreased ventricular filling = decreased CO (BP)Decreased ventricular filling = decreased CO (BP)Prolonged AF can cause stasis or pooling blood in the atria Prolonged AF can cause stasis or pooling blood in the atria (increased risk of thrombus)(increased risk of thrombus)Goals for treatment are aimed at rhythm conversion, rate Goals for treatment are aimed at rhythm conversion, rate control, and anticoagulation when indicated (digoxin, control, and anticoagulation when indicated (digoxin, amiodarone, diltiazem, cardioversion, heparin)amiodarone, diltiazem, cardioversion, heparin)

Junctional RhythmsJunctional Rhythms

Also called nodal or escape rhythmAlso called nodal or escape rhythmFoci driving the heart originate from the myocardial junctionFoci driving the heart originate from the myocardial junctionAtria depolarize in a retrograde fashion (from the junction Atria depolarize in a retrograde fashion (from the junction upward)upward)Result = inverted or absent (buried) P waves on the ECGResult = inverted or absent (buried) P waves on the ECGVentricle depolarizes in a downward (normal) fashionVentricle depolarizes in a downward (normal) fashionResult = normal QRS complexResult = normal QRS complexJR = inverted/absent P wave with normal QRSJR = inverted/absent P wave with normal QRS

Junctional RhythmsJunctional Rhythms

Intrinsic rate of junction = 40Intrinsic rate of junction = 40--6060Rhythm is regularRhythm is regularRate is usually 40Rate is usually 40--60 bpm60 bpmThree types = junctional rhythm, accelerated junctional Three types = junctional rhythm, accelerated junctional rhythm, junctional tachycardiarhythm, junctional tachycardiaCauses = digoxin toxicity, MI, ischemia, electrolyte Causes = digoxin toxicity, MI, ischemia, electrolyte imbalance, parasympathetic or sympathetic stimulation, and imbalance, parasympathetic or sympathetic stimulation, and cardiac myopathycardiac myopathyClinically similar to rate related signs & symptomsClinically similar to rate related signs & symptoms

Junctional RhythmsJunctional Rhythms

Junctional RhythmJunctional Rhythm

Accelerated JR/Junctional TachycardiaAccelerated JR/Junctional Tachycardia

Heart BlocksHeart Blocks

Common form of bradyarrhythmiaCommon form of bradyarrhythmia““BlockBlock”” refers to an interruption in cardiac conduction (like a refers to an interruption in cardiac conduction (like a road block or detour in traffic)road block or detour in traffic)All blocks have different conduction pathways (or detours) All blocks have different conduction pathways (or detours) measurable on ECGmeasurable on ECGPathways are impaired or completely disabled Pathways are impaired or completely disabled Most susceptible areas in the heart are the AV node and the Most susceptible areas in the heart are the AV node and the bundle of HISbundle of HISThe more sever the effect, the higher the degree of blockThe more sever the effect, the higher the degree of block

Heart BlocksHeart Blocks……BBBBBB

Term heart block can refer to a dysrhythmia or damage Term heart block can refer to a dysrhythmia or damage along the bundles of HISalong the bundles of HISBundle of HIS block = bundle branch blockBundle of HIS block = bundle branch blockBBB cannot be diagnosed from a single monitoring lead BBB cannot be diagnosed from a single monitoring lead (need 12(need 12--lead to determine accurately if right/left)lead to determine accurately if right/left)On 12 Lead = seen as an extra R wave (jagged R point) on On 12 Lead = seen as an extra R wave (jagged R point) on specific leads specific leads

A V B l o c k sA V B l o c k s ……

Types = first, second (type I and type II), Types = first, second (type I and type II), third degreethird degreeFairly easy to recognize using consistent Fairly easy to recognize using consistent landmarkslandmarksHeart rates are usually normal to slow Heart rates are usually normal to slow (often not detected on rate dependent (often not detected on rate dependent monitoring systems)monitoring systems)

AV BlocksAV Blocks……First Degree AVBFirst Degree AVB

Normal to slow rateNormal to slow rateRhythm is regular (normal RR interval, regular PP interval, Rhythm is regular (normal RR interval, regular PP interval, regular lengthened PR interval)regular lengthened PR interval)QRS is normalQRS is normalOnly abnormality is prolonged PR intervalOnly abnormality is prolonged PR intervalPR interval > 0.20 sec (5 small boxes) = 1st degree AVBPR interval > 0.20 sec (5 small boxes) = 1st degree AVBNonmalignant dysrhythmia (asymptomatic)Nonmalignant dysrhythmia (asymptomatic)May precede higher degree blockMay precede higher degree block

Second Degree AVBSecond Degree AVB……Mobitz I/WenckebachMobitz I/Wenckebach

Slow to normal rateSlow to normal rateCycles through AV node have increasing difficultyCycles through AV node have increasing difficultyOverall rhythm is irregularOverall rhythm is irregularPR interval gets longer with each QRS cycle, the last PR PR interval gets longer with each QRS cycle, the last PR delay is so long there is no conduction to ventricles and a delay is so long there is no conduction to ventricles and a QRS complex is droppedQRS complex is droppedIdentify by Irregular rhythm with variable PR intervalIdentify by Irregular rhythm with variable PR intervalCommon cause is digoxin toxicityCommon cause is digoxin toxicity

Second Degree AVBSecond Degree AVB……Type II/Mobitz IIType II/Mobitz II

Slow to normal rateSlow to normal rateRegular rhythm, regular RR interval, and regular PP Regular rhythm, regular RR interval, and regular PP interval, PR interval may be normal/prolongedinterval, PR interval may be normal/prolongedP:R ratio is greater than 1:1 (more Ps than QRS P:R ratio is greater than 1:1 (more Ps than QRS complexes)complexes)Identify by P waves without matching QRS and the Identify by P waves without matching QRS and the PR interval of all conducted P waves equalPR interval of all conducted P waves equalMay progress to third degree readilyMay progress to third degree readily

Third Degree AVBThird Degree AVB……Complete Heart BlockComplete Heart Block

Rate is slow to normal (often around 40)Rate is slow to normal (often around 40)LifeLife--threatening dysrhythmia (acutely compromises cardiac threatening dysrhythmia (acutely compromises cardiac output)output)Ventricular activity is regular (RVentricular activity is regular (R--R interval )R interval )PP--P interval is identical and regular (some P waves may be P interval is identical and regular (some P waves may be hidden by the QRS or T wave)hidden by the QRS or T wave)Atrium & ventricles are functioning independently of each Atrium & ventricles are functioning independently of each other (no relationship from Ps to QRS complexes) Atrial rate > other (no relationship from Ps to QRS complexes) Atrial rate > ventricular rateventricular rateIdentify by regular ventricular rhythm and variable PR intervalsIdentify by regular ventricular rhythm and variable PR intervals

AV BlocksAV Blocks……ACLS Sequence ACLS Sequence InterventionIntervention

Symptomatic or not?Symptomatic or not?No (report/observe/maintain ABCs)No (report/observe/maintain ABCs)YesYes……goals are aimed at fixing rate/conductiongoals are aimed at fixing rate/conduction1. Transcutaneous Pacemaker (TCP) (until TVP is 1. Transcutaneous Pacemaker (TCP) (until TVP is available)available)2. Atropine 0.5 mg IVP may repeat to total dose of 3 mg2. Atropine 0.5 mg IVP may repeat to total dose of 3 mg3. Dopamine 2 to 10 mcg/kg/min3. Dopamine 2 to 10 mcg/kg/min4. Epinephrine 2 to 10 mcg/min4. Epinephrine 2 to 10 mcg/min5. Prepare for transvenous pacing, treat contributing 5. Prepare for transvenous pacing, treat contributing causes.causes.Field, J.M., Gonzales, L., & Hazinski, M. F. (Eds.). (2006). AdvField, J.M., Gonzales, L., & Hazinski, M. F. (Eds.). (2006). Advanced cardiovascular life support provider manual. Dallas, anced cardiovascular life support provider manual. Dallas,

TX: American Heart Association.TX: American Heart Association.

Ventricular DysrhythmiaVentricular Dysrhythmia

Ventricular dysrhythmia compromise cardiac Ventricular dysrhythmia compromise cardiac output (almost always)output (almost always)Frequent precursor to cardiopulmonary arrestFrequent precursor to cardiopulmonary arrestDysrhythmia are either ventricular or Dysrhythmia are either ventricular or supraventricular, ventricular identified by widened supraventricular, ventricular identified by widened QRSQRSVentricular dysrhythmia originate from the ventricleVentricular dysrhythmia originate from the ventricle

Ventricular Tachycardia Ventricular Tachycardia (VTach/VT)(VTach/VT)

VT = run of three or more consecutive PVCsVT = run of three or more consecutive PVCsLifeLife--threateningthreateningMay occur with or without pulses (CO)May occur with or without pulses (CO)Rate is usually 100Rate is usually 100--220 bpm/Rhythm & regular220 bpm/Rhythm & regularP waves are not visualizedP waves are not visualizedQRS complexes are very wide (>0.12 sec)QRS complexes are very wide (>0.12 sec)Causes include MI, ischemia, acidosis, electrolyte Causes include MI, ischemia, acidosis, electrolyte imbalanceimbalance

VV--TachTach……ACLS Intervention ACLS Intervention SequenceSequence

Pulse Pulse

With pulse:With pulse:1. Oxygen1. Oxygen2. Establish IV access2. Establish IV access3. Amiodarone 150 mg IV 3. Amiodarone 150 mg IV over 10 minutes, repeat to over 10 minutes, repeat to max dose of 2.2 g/24 hoursmax dose of 2.2 g/24 hoursPrepare for synchronized Prepare for synchronized cardioversion. If unstable cardioversion. If unstable perform immediately after IV perform immediately after IV access.access.Field, J.M., Gonzales, L., & Hazinski, M. F. (Eds.). Field, J.M., Gonzales, L., & Hazinski, M. F. (Eds.). (2006). Advanced cardiovascular life support provider (2006). Advanced cardiovascular life support provider manual. Dallas, TX: American Heart Association.manual. Dallas, TX: American Heart Association.

Without pulse: (code)Without pulse: (code)1. Shock followed by 5 cycles 1. Shock followed by 5 cycles CPRCPR2. Shock, when IV access 2. Shock, when IV access available give vasopressor available give vasopressor (during CPR): Epinephrine 1mg (during CPR): Epinephrine 1mg IVP (q 3IVP (q 3--5min) 5min) or or Vasopressin 40 Vasopressin 40 units IV single dose 1 time in units IV single dose 1 time in place of 1place of 1stst or 2or 2ndnd dose of dose of EpinephrineEpinephrine3. Give 5 cycles of CPR between 3. Give 5 cycles of CPR between shocks. shocks. 4. Amiodarone 4. Amiodarone or or lidocaine lidocaine consider consider MagnesiumMagnesium

Ventricular FibrillationVentricular Fibrillation(V(V--Fib/VF)Fib/VF)

One of four types of cardiac arrest (asystole, pulseless VT, One of four types of cardiac arrest (asystole, pulseless VT, and PEA are others)and PEA are others)Most disorganized rhythm (cardiac cells depolarize Most disorganized rhythm (cardiac cells depolarize independently)independently)Myocardium has quivering muscle activity producing no Myocardium has quivering muscle activity producing no cardiac output (pulse)cardiac output (pulse)Irregular wavy baseline with no organized patternIrregular wavy baseline with no organized pattern

VV--fibfib……ACLS ACLS Sequence InterventionSequence Intervention

Definitive therapy for VF is defibrillationDefinitive therapy for VF is defibrillationABCD (code)ABCD (code)

1.1. Shock followed by 5 cycles CPRShock followed by 5 cycles CPR2.2. Shock, when IV access available give vasopressor Shock, when IV access available give vasopressor

(during CPR): Epinephrine 1mg IVP (q 3(during CPR): Epinephrine 1mg IVP (q 3--5min) 5min) or or Vasopressin 40 units IV single dose 1 time in place of Vasopressin 40 units IV single dose 1 time in place of 11stst or 2or 2ndnd dose of Epinephrinedose of Epinephrine

3.3. Give 5 cycles of CPR between shocks. Give 5 cycles of CPR between shocks. 4.4. Amiodarone Amiodarone or or lidocaine, consider lidocaine, consider MagnesiumMagnesiumField, J.M., Gonzales, L., & Hazinski, M. F. (Eds.). (2006). AdvField, J.M., Gonzales, L., & Hazinski, M. F. (Eds.). (2006). Advanced cardiovascular life support anced cardiovascular life support provider manual. Dallas, TX: American Heart Association.provider manual. Dallas, TX: American Heart Association.

Idioventricular RhythmsIdioventricular Rhythms

Slow, regular rhythm with wide ventricular complexesSlow, regular rhythm with wide ventricular complexesAbsent P wavesAbsent P wavesRate = 40 or lessRate = 40 or lessOriginates from ventriclesOriginates from ventriclesAssume VT with all wide complex tachycardias until proven Assume VT with all wide complex tachycardias until proven otherwiseotherwiseTreat based on symptomsTreat based on symptoms

Ventricular AsystoleVentricular AsystoleTranslated Translated without contractionswithout contractionsCompletely without electrical activityCompletely without electrical activityNo waves or complexes (may see P waves without No waves or complexes (may see P waves without QRS)QRS)AKA: cardiac or ventricular standstillAKA: cardiac or ventricular standstillCauses = MI, ischemia, hypokalemia, digoxin toxicity, Causes = MI, ischemia, hypokalemia, digoxin toxicity, prolonged sinus arrest, complete heart block, prolonged prolonged sinus arrest, complete heart block, prolonged hypoxiahypoxia

AsystoleAsystole……ACLS Sequence ACLS Sequence InterventionIntervention

ABCD of CPRABCD of CPRCall code (5 cycles of CPR)Call code (5 cycles of CPR)Check rhythm with defibrillatorCheck rhythm with defibrillatorVasopressor, Epinephrine 1 mg IV q 3Vasopressor, Epinephrine 1 mg IV q 3--5 minutes or 5 minutes or Vasopressin 40 U IV to replace 1Vasopressin 40 U IV to replace 1stst or 2or 2ndnd dose of dose of EpinephrineEpinephrineConsider Atropine 1 mg IV q 3Consider Atropine 1 mg IV q 3--5 minutes up to 3 doses5 minutes up to 3 dosesCheck rhythm q 5 cycles of CPRCheck rhythm q 5 cycles of CPRConsider ending codeConsider ending codeField, J.M., Gonzales, L., & Hazinski, M. F. (Eds.). (2006). AdvField, J.M., Gonzales, L., & Hazinski, M. F. (Eds.). (2006). Advanced cardiovascular life support anced cardiovascular life support provider manual. Dallas, TX: American Heart Association.provider manual. Dallas, TX: American Heart Association.

Where have we been?Where have we been?Cardiac anatomy & physiologyCardiac anatomy & physiologyECG basicsECG basics

WaveformsWaveformsMeasurementMeasurementNormal valuesNormal values

ECG InterpretationECG InterpretationAtrial ArrhythmiaAtrial ArrhythmiaJunctional ArrhythmiaJunctional ArrhythmiaHeart BlockHeart BlockVentricular ArrhythmiaVentricular Arrhythmia

InterventionsInterventions

Pediatric IntervalsPediatric IntervalsThe 6 month old infantThe 6 month old infant

PR interval 0.09 PR interval 0.09 –– 0.14 sec0.14 secQRS interval 0.03 QRS interval 0.03 –– 0.08 sec0.08 secHeart Rate 110 Heart Rate 110 –– 160/minute160/minute

The 2 year old childThe 2 year old childPR interval 0.10 PR interval 0.10 –– 0.15 sec0.15 secQRS interval 0.03 QRS interval 0.03 –– 0.08 sec0.08 secHeart Rate 90 Heart Rate 90 –– 140/minute140/minute

The 6 year old childThe 6 year old childPR interval 0.12 PR interval 0.12 –– 0.18 sec0.18 secQRS interval 0.04 QRS interval 0.04 –– 0.09 sec0.09 secHeart Rate 75 Heart Rate 75 –– 100/minute100/minute