Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1 Coronary...

Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1

Coronary ArteriesCoronary Arteries

Supply arterial blood Supply arterial blood to heart muscleto heart muscle Left coronary artery Left coronary artery

carries about 85% of carries about 85% of blood supply to blood supply to myocardiummyocardium

Right coronary artery Right coronary artery carries remaindercarries remainder

Originate above aortic Originate above aortic valvevalve


Left Coronary ArteryLeft Coronary Artery

Divides into left anterior Divides into left anterior descending and descending and circumflex arteriescircumflex arteries Left anterior descending Left anterior descending

(LAD) supplies:(LAD) supplies:• Anterior wall of left Anterior wall of left

ventricleventricle

• Interventricular septumInterventricular septum

Circumflex supplies:Circumflex supplies:• Lateral and posterior Lateral and posterior

portions of left ventricleportions of left ventricle

• Part of right ventriclePart of right ventricle


Coronary ArteriesCoronary Arteries

Right coronary artery Right coronary artery and left anterior and left anterior descending artery descending artery supply:supply: Most of right atrium Most of right atrium

and ventricleand ventricle Inferior aspect of left Inferior aspect of left

ventricleventricle Anastomoses provide Anastomoses provide

collateral circulationcollateral circulation


Coronary CapillariesCoronary Capillaries

Exchange nutrients and Exchange nutrients and metabolic wastesmetabolic wastes

Merge to form coronary Merge to form coronary veinsveins

Coronary sinus empties Coronary sinus empties into right atriuminto right atrium Major vein draining Major vein draining

myocardiummyocardium


ECG LeadsECG Leads

Two surface electrodes of opposite polarityTwo surface electrodes of opposite polarity Bipolar leadBipolar lead

• Two electrodes of opposite polarityTwo electrodes of opposite polarity

Unipolar leadUnipolar lead• Single positive electrode and reference pointSingle positive electrode and reference point


LeadsLeads Bipolar leadsBipolar leads

Limb leads Limb leads I, II, IIII, II, III

Unipolar leadsUnipolar leads Augmented limb leadsAugmented limb leads

• aVR, aVL, and aVFaVR, aVL, and aVF Precordial leadsPrecordial leads

• V1 through V6V1 through V6

Each lead assesses electrical activity from a Each lead assesses electrical activity from a different angledifferent angle


I, II, III Limb lead Bipolar

aVR, aVL, aVF Limb lead Unipolar

V1-V6 Chest lead Unipolar

Lead ComparisonLead Comparison


Lead Cardiac Surface Viewed

II, III, aVF Inferior wall

V1, V2 Septum

V3, V4 Anterior wall

V5, V6, I, aVL Lateral wall

Leads and Cardiac SurfacesLeads and Cardiac Surfaces


Standard Limb LeadsStandard Limb Leads

Record difference in Record difference in electrical potential electrical potential between left arm, between left arm, right arm, and left leg right arm, and left leg electrodeselectrodes

Represent axesRepresent axes


AxisAxis

Average direction of Average direction of the heart’s electrical the heart’s electrical activityactivity

Triaxial reference Triaxial reference systemsystem


AxisAxis

Lead I is a lateral Lead I is a lateral (leftward) lead(leftward) lead Assesses electrical Assesses electrical

activity from a activity from a viewpoint defined as 0viewpoint defined as 0°° on a circle divided into on a circle divided into an upper negative 180an upper negative 180°° and a lower positive and a lower positive 180180°°


AxisAxis

Leads II and III are Leads II and III are inferior leadsinferior leads Assess the heart's Assess the heart's

electrical activity from electrical activity from vantage points of +60vantage points of +60°° and +120and +120°°


Lead Positive Electrode Negative Electrode

I Left arm Right arm

II Left leg Right arm

III Left leg Left arm

Bipolar Lead PlacementBipolar Lead Placement

Limb lead placementLimb lead placement


Augmented Limb LeadsAugmented Limb Leads

Same electrodes as limb leadsSame electrodes as limb leads Record difference in electrical potential Record difference in electrical potential

between extremity lead sites and a reference between extremity lead sites and a reference pointpoint Zero electrical potential Zero electrical potential At center of the heart’s electrical fieldAt center of the heart’s electrical field



Axis of each lead is Axis of each lead is formed by line from formed by line from electrode site to electrode site to center of the heartcenter of the heart



aVR, aVL, and aVF leads intersect at angles aVR, aVL, and aVF leads intersect at angles different from those of the standard limb different from those of the standard limb leadsleads

Produce three other intersecting lines of Produce three other intersecting lines of referencereference With standard limb leads, these leads make up a With standard limb leads, these leads make up a

hexaxial reference systemhexaxial reference system


Lead aVRLead aVR

Distant recording Distant recording electrodeelectrode

Looks at heart from Looks at heart from right shoulderright shoulder


Lead aVLLead aVL

Lateral leadLateral lead Records electrical Records electrical

activity from left activity from left shoulder shoulder --3030°°


Lead aVFLead aVF

Inferior leadInferior lead Records electrical Records electrical

activity from left lower activity from left lower extremityextremity +90+90°°


Limb LeadsLimb Leads

Leads II, III, aVF Inferior leads

I, aVL Lateral leads


Modified Lead RecordingModified Lead Recording

Limb lead placement altered to mimic Limb lead placement altered to mimic precordial leads (Vprecordial leads (V11 through V through V66)) Modified chest leadsModified chest leads MCLMCL11 to MCL to MCL66

May help:May help: Distinguish between supraventricular tachycardia Distinguish between supraventricular tachycardia

with aberration and ventricular tachycardiawith aberration and ventricular tachycardia Diagnose bundle branch blocksDiagnose bundle branch blocks


MCLMCL11

Positive electrode in Positive electrode in VV11 position position 44thth intercostal space, intercostal space,

right of sternumright of sternum Negative electrode Negative electrode

placed anteriorlyplaced anteriorly Below lateral end of Below lateral end of

left clavicleleft clavicle


MCLMCL66

Positive electrode on Positive electrode on left midaxillary line at left midaxillary line at 55thth intercostal space intercostal space As for lead VAs for lead V66

Negative electrode Negative electrode placed anteriorly, placed anteriorly, below left shoulderbelow left shoulder


12-Lead ECG Monitoring12-Lead ECG Monitoring

10 electrodes10 electrodes Four limb leads (right arm, right leg, left arm, left Four limb leads (right arm, right leg, left arm, left

leg)leg)• Leads I, II, and III, and aVF, aVL, and aVRLeads I, II, and III, and aVF, aVL, and aVR

Six chest leads Six chest leads • VV11 through V through V66



Leads view left Leads view left ventricle from ventricle from position of its positive position of its positive electrodeelectrode



Identifies ST segment and T-wave changesIdentifies ST segment and T-wave changes Myocardial ischemia, injury, and infarctionMyocardial ischemia, injury, and infarction

Identifies VT in wide-complex tachycardiaIdentifies VT in wide-complex tachycardia Determines electrical axisDetermines electrical axis

Presence of fascicular blocksPresence of fascicular blocks Determines presence and location of bundle Determines presence and location of bundle

branch blocksbranch blocks


Precordial LeadsPrecordial Leads

Six precordial leads are projected through Six precordial leads are projected through anterior chest wall toward backanterior chest wall toward back

Positive leads are placed on chest in Positive leads are placed on chest in reference to thoracic landmarksreference to thoracic landmarks Record electrical activity in transverse or Record electrical activity in transverse or

horizontal planehorizontal plane


Precordial LeadsPrecordial Leads

VV11 and V and V22: Septal : Septal

leadsleads VV33 and V and V44: Anterior : Anterior

leadsleads VV44 through V through V66: Lateral : Lateral

leadsleads


12-Lead Electrode Application 12-Lead Electrode Application

...

Locate the jugular notchLocate the jugular notch Palpate for the angle of LouisPalpate for the angle of Louis


12-Lead Electrode Application12-Lead Electrode Application

Follow the angle of Louis to patient’sFollow the angle of Louis to patient’sright until it articulates with 2right until it articulates with 2ndnd rib rib

Locate the 2Locate the 2ndnd IC space IC space(immediately below 2(immediately below 2ndnd rib) rib)



VV11 is positioned in the 4 is positioned in the 4thth IC IC

space just right of the sternumspace just right of the sternumFrom the 2From the 2ndnd IC space, the 3 IC space, the 3rdrd and and

44thth IC spaces can be found IC spaces can be found



Place VPlace V22 electrode in the 4 electrode in the 4thth IC IC

space just left of sternumspace just left of sternumFrom VFrom V11, find the corresponding, find the corresponding

IC space on the left side of the sternumIC space on the left side of the sternum



From VFrom V22 position, locate 5 position, locate 5thth IC space, IC space,

follow to the midclavicular linefollow to the midclavicular linePosition VPosition V44 electrode in 5 electrode in 5thth IC space in IC space in

midclavicular linemidclavicular line



VV55 is positioned in is positioned in

anterior axillary line, level with Vanterior axillary line, level with V44Position VPosition V33 halfway between V halfway between V22 & V & V44



Position VPosition V66 in the midaxillary line, level with V in the midaxillary line, level with V44


ST SegmentST Segment

Early phase of Early phase of repolarization of repolarization of ventriclesventricles

Follows QRS complexFollows QRS complex Ends with onset of T Ends with onset of T

wavewave



ST segment “takes ST segment “takes off” from the QRS off” from the QRS complex at J pointcomplex at J point



Position of ST segment is commonly judged Position of ST segment is commonly judged using baseline of PR or TP interval for using baseline of PR or TP interval for referencereference ST segment elevationST segment elevation ST segment depressionST segment depression



Abnormal ST segmentsAbnormal ST segments InfarctionInfarction IschemiaIschemia PericarditisPericarditis After digitalis administrationAfter digitalis administration Other disease statesOther disease states


T WaveT Wave

Repolarization of Repolarization of ventricular cellsventricular cells

Last part of ventricular Last part of ventricular systolesystole

Above or below isoelectric Above or below isoelectric line line

Usually rounded and Usually rounded and slightly asymmetricalslightly asymmetrical


T WaveT Wave

Deep, symmetrically inverted T waves may Deep, symmetrically inverted T waves may suggest cardiac ischemiasuggest cardiac ischemia

T wave elevated more than half the height of T wave elevated more than half the height of the QRS complex may indicate: the QRS complex may indicate: Onset of myocardial ischemiaOnset of myocardial ischemia HyperkalemiaHyperkalemia


Note “Rabbit Ear”Note “Rabbit Ear”


12-Lead Strategies for12-Lead Strategies forWide-Complex Tachycardias Wide-Complex Tachycardias

The presence of right axis deviation (negative The presence of right axis deviation (negative QRS complex in lead I; positive QRS complex QRS complex in lead I; positive QRS complex in leads II and III) and a negative QRS in leads II and III) and a negative QRS complex in MCLcomplex in MCL11 (V (V11) indicates VT) indicates VT


Right Axis Deviation and a Right Axis Deviation and a Downward MCLDownward MCL11 Indicates VT Indicates VT


12-Lead Strategies for12-Lead Strategies forWide-Complex TachycardiasWide-Complex Tachycardias

VT if:VT if: All precordial leads (V leads) are either positive or All precordial leads (V leads) are either positive or

negative negative • Precordial concordancePrecordial concordance


VT-ConcordanceVT-Concordance


12-Lead Strategies for12-Lead Strategies forWide-Complex TachycardiasWide-Complex Tachycardias

RS interval >0.10 sec in any V lead RS interval >0.10 sec in any V lead indicates VTindicates VT

Increased ventricular activation timeIncreased ventricular activation time


Ventricular Conduction DisturbancesVentricular Conduction Disturbances

Bundle branch blocks or hemiblocksBundle branch blocks or hemiblocks Delay electrical transmission below bundle of Delay electrical transmission below bundle of

HisHis


Bundle Branch Blocks and HemiblocksBundle Branch Blocks and Hemiblocks Common causes of bundle branch blockCommon causes of bundle branch block

Ischemic heart diseaseIschemic heart disease Acute heart failureAcute heart failure Acute myocardial infarctionAcute myocardial infarction HyperkalemiaHyperkalemia TraumaTrauma CardiomyopathyCardiomyopathy Aortic stenosisAortic stenosis InfectionInfection


Bundle Branch AnatomyBundle Branch Anatomy

Bundle of His divides:Bundle of His divides: Left and right bundle branchesLeft and right bundle branches Right bundle branch continues toward apex and Right bundle branch continues toward apex and

spreads through right ventriclespreads through right ventricle Left bundle branch subdivides into anterior and Left bundle branch subdivides into anterior and

posterior fascicles and spreads through left ventricleposterior fascicles and spreads through left ventricle Electrical impulse conduction through Purkinje Electrical impulse conduction through Purkinje

fibers stimulates ventricular contractionfibers stimulates ventricular contraction





Normal conductionNormal conduction Left side of septum is stimulated firstLeft side of septum is stimulated first Electrical impulse traverses septum to stimulate Electrical impulse traverses septum to stimulate

other sideother side Left and right ventricles are then simultaneously Left and right ventricles are then simultaneously

stimulatedstimulated


Normal Ventricular Activation Normal Ventricular Activation


Bundle Branch BlockBundle Branch Block——ECGECG

One ventricle depolarizes and contracts One ventricle depolarizes and contracts before the otherbefore the other

Ventricular activation is not simultaneous, Ventricular activation is not simultaneous, therefore QRS complex widenstherefore QRS complex widens Slurred or notched appearanceSlurred or notched appearance

• ““Rabbit ears”Rabbit ears”

QRS complex is QRS complex is >>0.12 sec0.12 sec


Bundle Branch BlockBundle Branch Block

Criteria for bundle branch blockCriteria for bundle branch block QRS complex QRS complex >>0.12 sec0.12 sec QRS complexes produced by supraventricular QRS complexes produced by supraventricular

activityactivity


Bundle Branch BlockBundle Branch Block

Leads VLeads V11 and V and V66

MCLMCL11 and MCL and MCL66

Permit differentiation of right and left bundle Permit differentiation of right and left bundle branch blocksbranch blocks

Normal conductionNormal conduction VV11 (MCL (MCL11) is predominantly negative) is predominantly negative

QRS complex is 0.08-0.10 sec QRS complex is 0.08-0.10 sec


Right Bundle Branch BlockRight Bundle Branch Block

Left bundle branch performs normallyLeft bundle branch performs normally Activates left side of heart before rightActivates left side of heart before right ECG characteristicsECG characteristics

Initial negative deflection (S wave)Initial negative deflection (S wave) RSR-prime patternRSR-prime pattern QRS (or in this case, RSR) duration QRS (or in this case, RSR) duration >>0.12 sec0.12 sec


Right Bundle Branch Block Right Bundle Branch Block


Left Bundle Branch BlockLeft Bundle Branch Block

Fibers that fire interventricular septum are Fibers that fire interventricular septum are blocked:blocked: Alters normal septal activationAlters normal septal activation Sends it in opposite directionSends it in opposite direction

ECG characteristicsECG characteristics Initial Q wave in VInitial Q wave in V11 (MCL (MCL11))

R wave in VR wave in V11 (MCL (MCL11))

Deep, wide S wave (QS pattern)Deep, wide S wave (QS pattern) QRS duration QRS duration >>0.12 sec0.12 sec


Left Bundle Branch Block Left Bundle Branch Block


Left vs. Right BBBLeft vs. Right BBB

Find J point Find J point Draw line back into Draw line back into

QRS complexQRS complex Fill in triangle Fill in triangle

createdcreated Note direction Note direction

triangle pointstriangle points


Anterior HemiblockAnterior Hemiblock More common than posterior hemiblockMore common than posterior hemiblock Anterior fascicle of left bundle branch is a longer Anterior fascicle of left bundle branch is a longer

and thinner structureand thinner structure Blood supply primarily from left anterior Blood supply primarily from left anterior

descending (LAD) coronary arterydescending (LAD) coronary artery Anterior hemiblock characterized by left axis Anterior hemiblock characterized by left axis

deviation in patient with supraventricular rhythmdeviation in patient with supraventricular rhythm


Anterior HemiblockAnterior Hemiblock

Other ECG findings in anterior hemiblock:Other ECG findings in anterior hemiblock: Normal QRS complex (<0.12 sec) or a right Normal QRS complex (<0.12 sec) or a right

bundle branch blockbundle branch block Small Q wave followed by tall R wave in lead ISmall Q wave followed by tall R wave in lead I Small R wave followed by deep S wave in lead IIISmall R wave followed by deep S wave in lead III

High risk to develop complete heart blockHigh risk to develop complete heart block


Anterior HemiblockAnterior HemiblockShowing 1 Block of 3 FasciclesShowing 1 Block of 3 Fascicles


Posterior HemiblockPosterior Hemiblock

Right axis deviation with normal QRS Right axis deviation with normal QRS complex or right bundle branch blockcomplex or right bundle branch block

Other ECG findingsOther ECG findings Small R wave followed by deep S wave in lead ISmall R wave followed by deep S wave in lead I Small Q wave followed by tall R wave in lead IIISmall Q wave followed by tall R wave in lead III


Posterior HemiblockPosterior HemiblockShowing 2 of 3 Fascicles BlockedShowing 2 of 3 Fascicles Blocked


Bifascicular BlockBifascicular Block 2 of 3 pathways for ventricular conduction 2 of 3 pathways for ventricular conduction

blockedblocked Right bundle branch block with anterior or posterior Right bundle branch block with anterior or posterior

hemiblockhemiblock Left bundle branch blockLeft bundle branch block

Compromises myocardial contractility and Compromises myocardial contractility and cardiac outputcardiac output

May develop complete heart block suddenly May develop complete heart block suddenly


Multilead Determination of Axis and Multilead Determination of Axis and HemiblocksHemiblocks

Identifying axis can be useful in Identifying axis can be useful in determining the presence of hemiblocksdetermining the presence of hemiblocks

Best evaluated by looking at the QRS Best evaluated by looking at the QRS complexes in leads I, II, and IIIcomplexes in leads I, II, and III



Axis is:Axis is: Normal if QRS deflection is positive in bipolar leadsNormal if QRS deflection is positive in bipolar leads Physiological left (normal in some patients) when QRS Physiological left (normal in some patients) when QRS

deflection is:deflection is:• Positive in leads I and IIPositive in leads I and II

• Negative (inverted) in lead IIINegative (inverted) in lead III

Pathological left when QRS deflection is:Pathological left when QRS deflection is:• Positive in lead IPositive in lead I

• Negative in leads II and III (indicating an anterior hemiblock)Negative in leads II and III (indicating an anterior hemiblock)



Right axis when QRS deflection is:Right axis when QRS deflection is: Negative in lead I, negative or positive in lead IINegative in lead I, negative or positive in lead II Positive in lead III (pathological in any adult)Positive in lead III (pathological in any adult) Indicative of posterior hemiblockIndicative of posterior hemiblock

Extreme right (“No man’s land”) when QRS Extreme right (“No man’s land”) when QRS deflection is negative in all three leadsdeflection is negative in all three leads Rhythm is ventricular in originRhythm is ventricular in origin


Acute Coronary SyndromesAcute Coronary Syndromes

Acute myocardial infarction (AMI)Acute myocardial infarction (AMI) Unstable angina (UA)Unstable angina (UA) Treatment goalsTreatment goals

Reduce myocardial necrosisReduce myocardial necrosis Prevent major adverse cardiac eventsPrevent major adverse cardiac events Treat acute complications of ACSTreat acute complications of ACS


AtherosclerosisAtherosclerosis

Progressive narrowing of lumen of medium and Progressive narrowing of lumen of medium and large arteries large arteries Aorta and its branches, cerebral arteries, coronary Aorta and its branches, cerebral arteries, coronary

arteriesarteries Development of thick, hard, atherosclerotic Development of thick, hard, atherosclerotic

plaques called plaques called atheromasatheromas or or atheromatousatheromatous lesionslesions Commonly found in areas of turbulent blood flowCommonly found in areas of turbulent blood flow


AtherosclerosisAtherosclerosis——Risk FactorsRisk Factors

AgeAge Earlier in men than womenEarlier in men than women Family historyFamily history DiabetesDiabetes SmokingSmoking HypertensionHypertension HypercholesterolemiaHypercholesterolemia


AtherosclerosisAtherosclerosis——EffectsEffects

Disrupts intimal surface, causing loss of Disrupts intimal surface, causing loss of vessel elasticity and increase in vessel elasticity and increase in thrombogenesisthrombogenesis Atheroma reduces diameter of vessel lumenAtheroma reduces diameter of vessel lumen Decreases blood supply to tissuesDecreases blood supply to tissues


Angina PectorisAngina Pectoris

Symptom of myocardial ischemiaSymptom of myocardial ischemia ““Choking” pain in the chestChoking” pain in the chest Imbalance between myocardial oxygen supply Imbalance between myocardial oxygen supply

and demandand demand Accumulation of lactic acid and carbon dioxide Accumulation of lactic acid and carbon dioxide

in ischemic tissues of myocardiumin ischemic tissues of myocardium Metabolites irritate nerve endings and produce painMetabolites irritate nerve endings and produce pain



CausesCauses Atherosclerotic disease of the coronary arteriesAtherosclerotic disease of the coronary arteries Temporary occlusion due to coronary artery Temporary occlusion due to coronary artery

spasm with or without atherosclerosis spasm with or without atherosclerosis • Prinzmetal's angina Prinzmetal's angina



Pain described as pressure, squeezing, Pain described as pressure, squeezing, heaviness, or tightness in chestheaviness, or tightness in chest 30% feel pain only in chest30% feel pain only in chest Others describe as radiating to shoulders, arms, Others describe as radiating to shoulders, arms,

neck, and jaw and through to backneck, and jaw and through to back Associated signs and symptomsAssociated signs and symptoms

AnxietyAnxiety Shortness of breathShortness of breath Nausea or vomitingNausea or vomiting DiaphoresisDiaphoresis


Stable AnginaStable Angina Usually caused by physical exertion or Usually caused by physical exertion or

emotional stressemotional stress Pain lasts 1-5 minPain lasts 1-5 min

May last as long as 15 minMay last as long as 15 min Relieved by rest, nitroglycerin, or oxygenRelieved by rest, nitroglycerin, or oxygen ““Attacks” are usually similar in natureAttacks” are usually similar in nature Always relieved by same therapyAlways relieved by same therapy


Unstable AnginaUnstable Angina Preinfarction anginaPreinfarction angina Anginal pattern that has changed in its ease Anginal pattern that has changed in its ease

of onset, frequency, intensity, duration, or of onset, frequency, intensity, duration, or qualityquality

Includes “new onset” anginal chest painIncludes “new onset” anginal chest pain May occur during exercise or at restMay occur during exercise or at rest Pain lasts Pain lasts >>10 min10 min Less promptly relieved than stable anginaLess promptly relieved than stable angina


Unstable AnginaUnstable Angina——Management Management

Place patient at restPlace patient at rest Administer oxygenAdminister oxygen Administer aspirin (per protocol)Administer aspirin (per protocol) IV therapy IV therapy Pharmacological therapyPharmacological therapy

NitroglycerinNitroglycerin MorphineMorphine

Monitor ECGMonitor ECG Transport as soon as possibleTransport as soon as possible


Myocardial InfarctionMyocardial Infarction

Sudden and total occlusion or near-occlusion Sudden and total occlusion or near-occlusion of blood flowing through affected coronary of blood flowing through affected coronary arteryartery

Ischemia, injury, and necrosis of myocardium Ischemia, injury, and necrosis of myocardium distal to occlusiondistal to occlusion

Often associated with atherosclerotic heart Often associated with atherosclerotic heart disease (ASHD)disease (ASHD)

Precipitating eventsPrecipitating events


Types and Locations of InfarctsTypes and Locations of Infarcts

Infarction distal to occluded arteryInfarction distal to occluded artery Size of infarct determined by:Size of infarct determined by:

Metabolic needs of tissue supplied by occluded Metabolic needs of tissue supplied by occluded vesselvessel

Collateral circulationCollateral circulation Time until flow is reestablishedTime until flow is reestablished



Emergency careEmergency care Increasing oxygen supply Increasing oxygen supply Decreasing metabolic needs Decreasing metabolic needs Providing collateral circulationProviding collateral circulation Reestablishing perfusion to ischemic myocardium Reestablishing perfusion to ischemic myocardium

quicklyquickly



Most AMIs involve ventricle or Most AMIs involve ventricle or interventricular septum, which is supplied interventricular septum, which is supplied by either of two major coronary arteriesby either of two major coronary arteries Some patients sustain damage to right ventricleSome patients sustain damage to right ventricle



Anterior, lateral, or septal wall infarctionAnterior, lateral, or septal wall infarction Usually left coronary artery occlusionUsually left coronary artery occlusion

Inferior wall infarction Inferior wall infarction Usually right coronary artery occlusionUsually right coronary artery occlusion


Myocardial InfarctionMyocardial Infarction

Three ischemic syndromes Three ischemic syndromes Based on rupture of an unstable plaque in an Based on rupture of an unstable plaque in an

epicardial arteryepicardial artery Unstable anginaUnstable angina Non-ST-elevation myocardial infarctionNon-ST-elevation myocardial infarction ST-elevation myocardial infarctionST-elevation myocardial infarction


InfarctionInfarction Unstable anginaUnstable angina

Thrombus has not completely obstructed coronary Thrombus has not completely obstructed coronary flowflow

Intermittent ischemic episodeIntermittent ischemic episode May lead to complete occlusion and AMIMay lead to complete occlusion and AMI

Non-ST-elevation MINon-ST-elevation MI ST-segment depressionST-segment depression T-wave abnormalitiesT-wave abnormalities


InfarctionInfarction

ST-elevation MIST-elevation MI Q-wave MIQ-wave MI

• Pathological Q wavesPathological Q waves > 5 mm in depth> 5 mm in depth > 0.04 sec in duration in > 0.04 sec in duration in

>>2 contiguous leads2 contiguous leads


Death of MyocardiumDeath of Myocardium After blood flow to myocardium stops, cells After blood flow to myocardium stops, cells

switch to anaerobic metabolismswitch to anaerobic metabolism Produces ischemic pain (angina)Produces ischemic pain (angina)

Cells begin to swell and depolarizeCells begin to swell and depolarize If collateral flow and reperfusion are If collateral flow and reperfusion are

inadequate, much of muscle dies distal to inadequate, much of muscle dies distal to occlusion occlusion


Area of InfarctionArea of Infarction


Myocardial InfarctionMyocardial Infarction——DeathsDeaths

Lethal dysrhythmiasLethal dysrhythmias• VTVT

• VFVF

• Cardiac standstillCardiac standstill Pump failurePump failure

• Cardiogenic shockCardiogenic shock

• CHFCHF Myocardial tissue ruptureMyocardial tissue rupture

• Ventricle, septum, or papillary muscleVentricle, septum, or papillary muscle


MIMI——Signs and SymptomsSigns and Symptoms

Pain is similar to anginaPain is similar to angina May radiate to arms, neck, jaw, or backMay radiate to arms, neck, jaw, or back DyspneaDyspnea AnxietyAnxiety AgitationAgitation Sense of impending doomSense of impending doom Nausea and vomitingNausea and vomiting DiaphoresisDiaphoresis CyanosisCyanosis PalpitationsPalpitations


MIMI——Signs and SymptomsSigns and Symptoms

Chest pain often constantChest pain often constant Not altered by nitroglycerin or medications, Not altered by nitroglycerin or medications,

rest, changes in body position, or breathing rest, changes in body position, or breathing patternspatterns Onset of pain at rest in >50% of MI patientsOnset of pain at rest in >50% of MI patients Most have experienced warning anginal pain Most have experienced warning anginal pain

(preinfarction angina) hours or days before(preinfarction angina) hours or days before


Myocardial InfarctionMyocardial Infarction——ECG FindingsECG Findings

Heart muscle unable to contract effectivelyHeart muscle unable to contract effectively Remains in depolarized stateRemains in depolarized state

Current flow between pathologically depolarized Current flow between pathologically depolarized and normally repolarized areas can produce:and normally repolarized areas can produce:• Abnormal ST segment elevationAbnormal ST segment elevation

• Ischemic ST segment depressionIschemic ST segment depression

• Normal or non-diagnostic ECG changesNormal or non-diagnostic ECG changes


Myocardial InfarctionMyocardial Infarction——ECG FindingsECG Findings

ST-Segment Elevation MI (STEMI)ST-Segment Elevation MI (STEMI) ST segment elevation >1 mm in 2 adjacent leadsST segment elevation >1 mm in 2 adjacent leads new LBBBnew LBBB

High-Risk UA/non-ST-Elevation MI (NSTEMI)High-Risk UA/non-ST-Elevation MI (NSTEMI) ST segment depression >0.5 mm lasting 20 min.ST segment depression >0.5 mm lasting 20 min. T-wave inversion with painT-wave inversion with pain

Normal or nondiagnostic ECG changesNormal or nondiagnostic ECG changes Inconclusive changes Inconclusive changes


Myocardial Infarction ECG ImpostersMyocardial Infarction ECG Imposters

Left bundle branch blockLeft bundle branch block Some ventricular rhythmsSome ventricular rhythms Left ventricular hypertrophyLeft ventricular hypertrophy PericarditisPericarditis Ventricular aneurysmVentricular aneurysm Early repolarizationEarly repolarization


Myocardial InfarctionMyocardial Infarction——ManagementManagement

Oxygen Oxygen AspirinAspirin NitroglycerinNitroglycerin MorphineMorphine 12-lead ECG12-lead ECG Fibrinolytic screeningFibrinolytic screening Transport to appropriate facilityTransport to appropriate facility


ST Segment Elevation Likely with ST Segment Elevation Likely with Acute Injury Acute Injury


RightRight ventricleV4R, V5R, V6R

LeftLateral wallI, aVL, V5, V6

LeftAnterior wall(most lethal)

V3, V4

LeftSeptal wallV1, V2

RightInferior wall(most common)

II, III, aVF

Coronary Artery Involved

Location of InfarctionLead

ST-Elevation and Infarct LocationST-Elevation and Infarct Location


Multilead Assessment of the Multilead Assessment of the HeartHeart


Left Ventricular Failure (LVF) and Left Ventricular Failure (LVF) and Pulmonary EdemaPulmonary Edema

Left ventricle fails to function as an effective Left ventricle fails to function as an effective forward pumpforward pump

Causes back-pressure of blood into pulmonary Causes back-pressure of blood into pulmonary circulationcirculation


LVF and Pulmonary EdemaLVF and Pulmonary Edema

Caused by heart disease, including:Caused by heart disease, including: IschemicIschemic ValvularValvular Hypertensive heart diseaseHypertensive heart disease

Untreated LVF leads to pulmonary edemaUntreated LVF leads to pulmonary edema


LVFLVF——Signs and SymptomsSigns and Symptoms

Respiratory distressRespiratory distress Apprehension, agitation, confusionApprehension, agitation, confusion Cyanosis (if severe)Cyanosis (if severe) DiaphoresisDiaphoresis Adventitious lung soundsAdventitious lung sounds JVDJVD Abnormal vital signsAbnormal vital signs


Pulmonary EdemaPulmonary Edema——ManagementManagement

Oxygen, IV, monitorOxygen, IV, monitor 12-lead ECG12-lead ECG Nitroglycerin (SBP >100)Nitroglycerin (SBP >100) FurosemideFurosemide MorphineMorphine CPAPCPAP Reversible causesReversible causes Dobutamine or dopamine for shockDobutamine or dopamine for shock


Right Ventricular Failure (RVF)Right Ventricular Failure (RVF)

Right ventricle fails as effective forward pumpRight ventricle fails as effective forward pump Back-pressure of blood into systemic venous Back-pressure of blood into systemic venous

circulationcirculation


RVFRVF

Causes Causes Chronic hypertension (LVF precedes RVF)Chronic hypertension (LVF precedes RVF) COPDCOPD Pulmonary embolismPulmonary embolism Valvular heart diseaseValvular heart disease Right ventricular infarctionRight ventricular infarction

RVF usually results from LVFRVF usually results from LVF


RVFRVF

Signs and symptomsSigns and symptoms TachycardiaTachycardia Venous congestionVenous congestion

• Engorged liver, spleen, or bothEngorged liver, spleen, or both

• Venous distentionVenous distention

• Peripheral edemaPeripheral edema

Fluid accumulation in serous cavitiesFluid accumulation in serous cavities ManagementManagement


Cardiogenic ShockCardiogenic Shock

Most extreme form of pump failureMost extreme form of pump failure Left ventricular function is so compromised Left ventricular function is so compromised

heart cannot meet metabolic needs of bodyheart cannot meet metabolic needs of body Extensive myocardial infarctionExtensive myocardial infarction

40% of left ventricle40% of left ventricle Diffuse ischemiaDiffuse ischemia


Cardiac TamponadeCardiac Tamponade Impaired diastolic filling of heart Impaired diastolic filling of heart Increased fluid in pericardial spaceIncreased fluid in pericardial space Volume of pericardial fluid encroaches on Volume of pericardial fluid encroaches on

capacity of atria and ventricles to fill capacity of atria and ventricles to fill adequatelyadequately

Ventricular filling is mechanically limited, and Ventricular filling is mechanically limited, and stroke volume is decreasedstroke volume is decreased


Cardiac TamponadeCardiac Tamponade

Acute onsetAcute onset TraumaTrauma

Gradual onsetGradual onset NeoplasmNeoplasm InfectionInfection Renal diseaseRenal disease HypothyroidismHypothyroidism

ManagementManagement FluidFluid PericardiocentesisPericardiocentesis

PresentationPresentation Chest painChest pain TachycardiaTachycardia EctopyEctopy JVDJVD Decreased SBPDecreased SBP Pulsus paradoxusPulsus paradoxus Muffled heart soundsMuffled heart sounds ECG changesECG changes


Thoracic and Abdominal Thoracic and Abdominal Aortic AneurysmsAortic Aneurysms

AneurysmAneurysm Dilation of a vesselDilation of a vessel

CausesCauses Atherosclerotic disease (most common)Atherosclerotic disease (most common) Infectious disease (primarily syphilis)Infectious disease (primarily syphilis) Traumatic injuryTraumatic injury Certain genetic disorders (e.g., Marfan's Certain genetic disorders (e.g., Marfan's

syndrome)syndrome)


Aortic AneurysmsAortic Aneurysms——Signs and Signs and SymptomsSymptoms

HypotensionHypotension SyncopeSyncope Abdominal or back Abdominal or back

painpain Tearing or rippingTearing or ripping

Low back or flank Low back or flank pain pain Radiates to thigh, Radiates to thigh,

groin, testiclegroin, testicle

Peritoneal irritationPeritoneal irritation Urge to defecateUrge to defecate Pulsatile, tender massPulsatile, tender mass Distal pulses present Distal pulses present

or absentor absent GI bleedingGI bleeding


Branches of Aorta Branches of Aorta


Pathogenesis of Dissecting Pathogenesis of Dissecting AneurysmsAneurysms

Medial and intimal degeneration Medial and intimal degeneration in aortic wallin aortic wall

Hemodynamic forces produce Hemodynamic forces produce tear tear

Dissecting hematoma Dissecting hematoma propagated by pulse wavepropagated by pulse wave


Dissecting AneurysmsDissecting Aneurysms—Management—Management

Gentle handlingGentle handling OxygenOxygen MonitorMonitor IV fluidsIV fluids

Bolus if profound shockBolus if profound shock


Acute Arterial OcclusionAcute Arterial Occlusion

Blockage of arterial flow caused by:Blockage of arterial flow caused by: TraumaTrauma EmbolusEmbolus ThrombosisThrombosis

Severity of episode depends on:Severity of episode depends on: Site of occlusionSite of occlusion Collateral circulationCollateral circulation


Acute Arterial OcclusionAcute Arterial Occlusion Signs and symptomsSigns and symptoms

Pain in extremity Pain in extremity • May be severe and sudden in onset or absent because May be severe and sudden in onset or absent because

of paresthesiaof paresthesia PallorPallor Cool skin distal to occlusionCool skin distal to occlusion Change in sensory and motor functionChange in sensory and motor function Diminished or absent pulse distal to injuryDiminished or absent pulse distal to injury Bruit over affected vesselBruit over affected vessel Slow capillary fillingSlow capillary filling Sometimes shockSometimes shock


Arterial OcclusionArterial Occlusion—Management—Management

Extremity occlusion is painful and limb Extremity occlusion is painful and limb threatening if blood flow is not reestablished threatening if blood flow is not reestablished within 4-8 hrswithin 4-8 hrs

Immobilize limb and transportImmobilize limb and transport Patients with mesenteric occlusionPatients with mesenteric occlusion

Manage for shock:Manage for shock:• OxygenOxygen

• IV fluidsIV fluids

Analgesics for pain controlAnalgesics for pain control


Common Sites ofCommon Sites ofEmbolic Arterial OcclusionEmbolic Arterial Occlusion


Venous ThrombosisVenous Thrombosis

Predisposing factorsPredisposing factors History of traumaHistory of trauma SepsisSepsis Stasis or inactivityStasis or inactivity Recent immobilizationRecent immobilization PregnancyPregnancy Birth control pillsBirth control pills MalignancyMalignancy CoagulopathiesCoagulopathies SmokingSmoking Varicose veinsVaricose veins


Acute Deep Vein Thrombosis (DVT)Acute Deep Vein Thrombosis (DVT)

Occlusion of deep veins is serious, common Occlusion of deep veins is serious, common problemproblem

May involve any portion of deep venous May involve any portion of deep venous systemsystem More common in lower extremitiesMore common in lower extremities


Acute DVTAcute DVT——Risk FactorsRisk Factors

Lower extremity Lower extremity traumatrauma

Recent surgeryRecent surgery Advanced ageAdvanced age Recent MIRecent MI InactivityInactivity

Previous thrombosisPrevious thrombosis Oral contraceptivesOral contraceptives CancerCancer ObesityObesity CHFCHF


Acute DVTAcute DVT——ManagementManagement

Risk of pulmonary embolusRisk of pulmonary embolus HospitalizationHospitalization Bed restBed rest AnticoagulantsAnticoagulants


Common Sites ofCommon Sites ofAtherosclerotic Occlusive DiseaseAtherosclerotic Occlusive Disease


HypertensionHypertension

Resting BP: Consistently >140/90 mm HgResting BP: Consistently >140/90 mm Hg Several categories of hypertension based on Several categories of hypertension based on

level of blood pressure, symptoms, and level of blood pressure, symptoms, and urgency of need for interventionurgency of need for intervention


Chronic HypertensionChronic Hypertension

Conditions associated with chronic, Conditions associated with chronic, uncontrolled hypertensionuncontrolled hypertension Cerebral hemorrhage and strokeCerebral hemorrhage and stroke Myocardial infarctionMyocardial infarction Renal failure (secondary to vascular changes in Renal failure (secondary to vascular changes in

the kidney)the kidney) Thoracic and/or abdominal aortic aneurysmThoracic and/or abdominal aortic aneurysm


Hypertensive EmergenciesHypertensive Emergencies

Blood pressure increase leads to significant, Blood pressure increase leads to significant, irreversible end-organ damage within hours if irreversible end-organ damage within hours if not treatednot treated

Organs most at risk are brain, heart, and Organs most at risk are brain, heart, and kidneyskidneys



Myocardial ischemia with hypertensionMyocardial ischemia with hypertension Aortic dissection with hypertensionAortic dissection with hypertension Pulmonary edema with hypertensionPulmonary edema with hypertension Hypertensive intracranial hemorrhageHypertensive intracranial hemorrhage ToxemiaToxemia Hypertensive encephalopathyHypertensive encephalopathy


Hypertensive EmergenciesHypertensive Emergencies——Signs and Signs and SymptomsSymptoms

Paroxysmal Paroxysmal nocturnal dyspneanocturnal dyspnea

Shortness of breathShortness of breath Altered mental Altered mental

statusstatus VertigoVertigo HeadacheHeadache EpistaxisEpistaxis

TinnitusTinnitus Changes in visual Changes in visual

acuityacuity Nausea and vomitingNausea and vomiting SeizuresSeizures ECG changesECG changes


Hypertensive EncephalopathyHypertensive Encephalopathy

Severe hypertension produces hypertensive Severe hypertension produces hypertensive encephalopathy and cerebral hypoperfusionencephalopathy and cerebral hypoperfusion

Loss of integrity of blood-brain barrierLoss of integrity of blood-brain barrier Fluid exudation into brain tissueFluid exudation into brain tissue


Hypertensive EncephalopathyHypertensive Encephalopathy

Progresses from:Progresses from: Severe headache, nausea, vomiting, aphasia, Severe headache, nausea, vomiting, aphasia,

hemiparesis, and transient blindnesshemiparesis, and transient blindness LaterLater

Seizures, stupor, coma, and deathSeizures, stupor, coma, and death



Supportive careSupportive care OxygenOxygen IVIV ECG monitoringECG monitoring Rapid transportRapid transport Drugs under medical supervisionDrugs under medical supervision


Techniques for ManagingTechniques for ManagingCardiac EmergenciesCardiac Emergencies

Basic life supportBasic life support Mechanical CPR devicesMechanical CPR devices Monitor-defibrillatorsMonitor-defibrillators Implantable cardioverter-defibrillators (ICDs)Implantable cardioverter-defibrillators (ICDs) Transcutaneous cardiac pacing (TCP)Transcutaneous cardiac pacing (TCP) Advanced cardiac life support (ACLS) systemAdvanced cardiac life support (ACLS) system

Date post:	17-Jan-2016
Category:	Documents
Upload:	veronica-stewart
View:	213 times
Download:	0 times

Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc. 1 Coronary...

Documents