ECG_document.docx

10/21/23, 11:43 AM Electrocardiography Notes: Diagrams & Illustrations | Osmosis https://www.osmosis.org/notes/Electrocardiography#page-1 1/8 NOTES NOTES I ELECTROCARDIOGRAPHY(ECG) ECG BASICS osms.iV^CG-basics ECG traces provide inormation on heart’s electrical actiity, rate, rhythm ° Depolariza...

10/21/23, 11:43 AM Electrocardiography Notes: Diagrams & Illustrations | Osmosis https://www.osmosis.org/notes/Electrocardiography#page-1 1/8 NOTES NOTES I ELECTROCARDIOGRAPHY(ECG) ECG BASICS osms.iV^CG-basics ECG traces provide inormation on heart’s electrical actiity, rate, rhythm ° Depolarization waes moving towards electrode —> positive delection = Depolarization waes moving away rom electrode —> negative delection 12 lead ECG (EKG) records heart electrical actiity during hearteat - Six lim leads I, II, III, AVR, AVL, AVF) ° Six chest leads (V1-V6) P wae: atrial depolarization - PR interval: eginning o atrial contraction to eginning o ventricular contraction time or impulse to reach ventricles orm sinus node ° PR segment: end o P wae to eginning o QRS complex; signiies AV nodal delay QRS complex: ventricular depolarization T wae: ventricular repolarization QT interval: time rom start o Q wae to end oT wae represents time taen or ventricular depolarization, repolarization U wae: sometimes seen ater T wae not shown, represents purine ier repolarization RECORDING ECGs ecorded on 1mm graph paper 10mm = lm CORONAL PLAME Figure 18.1 ead placement in the coronal and transverse plane. 128 OSMOSIS.ORG 10/21/23, 11:43 AM Electrocardiography Notes: Diagrams & Illustrations | Osmosis https://www.osmosis.org/notes/Electrocardiography#page-1 2/8 Chapter 18 Cardiovascular hysiology: Electrocardiography - x-axis = time 1mm = 0.04s ° y- axis = voltage 10mm = Im im leads: I, II, III, AVR, AVL, AVF ° ipolar leads: I, II, III - nipolar leads: AVR, AVL, AVF augmented voltage or right arm, let arm, letoot ° ateral leads: I, a, V5, V6 - Inerior leads: II, III, AVF - Six lim leads provide six iewpoints o cardiac actiity, in rontal plane ° Electrodes placed on shoulders, adomen to record lim leads hest leads precordial: VI -V6 °eptal leads: VI,V2 ° ateral leads: V5,V6 ° Anterior leads: V3,V4 - Six chest leads provide six iewpoints o cardiac actiity, in horizontal plane ECG NORMAL SINUS RHYTHM osmns.it/ECG-norynal-sinus-rhyihYn P waes precede QRS complexes in 1:1 relationship SA node sinus node, dominant centre o automaticity - Normal sinus rhythm 50-0pm onstant RR interval redictale recurring wae pattern -waes, QRS, T waes P waes - pright in leads I, II, AVF ° Amplitude < 2.5mm in lim leads - inus arrhythmia: can e normal i sinus rate varies with respiratory cycle, relatiely mild/anormal i sinus rate varies unpredictaly.ery dramatic ECG RATE & RHYTHM osYns.it/ECG-rate-rhythYn RATE DETERMINATION Box method: measure R-R interval y large boxes ° ECG grid: thic lines 5mm apart 0.20s thin lines 1mm 0.04s - ocate R wae pea on thic line as “start'' - ael locs thic lines: 300; 150; 100; 75; 60; 50 ° ocate next R wae peato estimate heart rate ast heart rates: use ine division within boxes or more accurate estimates low heart rates: use 2.5s mars at top o trace paper ° ocate R wae pea on large loc line as “start" ° ount suseuent numer ocomplete R waes in 10s strip total strip o calculate heart rate ° ount numer oQRS complexes across entire recording, multiply y six or heart rate used to estimate heart rate during irregular rhythms (OSMuSIS.org 2023 Edition OSMOSIS.ORG 129 10/21/23, 11:43 AM Electrocardiography Notes: Diagrams & Illustrations | Osmosis https://www.osmosis.org/notes/Electrocardiography#page-1 3/8 rate. ECG INTERVALS osvns.it/ECG-intervals PR INTERVAL & SEGMENT Normal interval 0.12-0.20s - Measure durations rom start o P to start o Q Normal segment: usually isoelectric, may e displaced QRS INTERVAL Normal QRS: <0.10-0.12s slight variation etween reerences ° Measured rom start o Q to end o S QRS amplitude (voltage): wide range o normal limits ° ow voltage: < 5mm lim leads, < 10mm chest leads ° Increased voltage can indicate let ventricular hypertrophy, right ventricular hypertrophy, may e normal ° Narrow (< 0.12s I wide (> 0.12s QT INTERVAL Normal QT < 50 RR interval, only or normal heart rates Measure QT rom start o Q to end oT Measure RR interval as time etween R-R ° c interval corrected or heart rate 0.35-0.44s or normal heart rate 60-100pm ° ong c (> 500ms — prone to rapid, potentially atal ventricular rhythm @G0bpm Figure 18.3 An ECG interval includes a segment and one or more waes and should e completed within a speciic amount o time to e considered healthy. (OSM0SIS.org 2023 Edition 130 OSMOSIS.ORG 10/21/23, 11:43 AM Electrocardiography Notes: Diagrams & Illustrations | Osmosis https://www.osmosis.org/notes/Electrocardiography#page-1 4/8 Chapter 18 Cardiovascular hysiology: Electrocardiography ECG AXIS osYns.it/CCG-axis Mean direction (vector) o ventricular depolarization waeront ° Mean QRS vector normally downward rom AV node through stronger let ventricle Normal axis range -30° to +90° orontal plane im leads indicate vector deviation in rontal plane ° Divided into our uadrants Figure 18.4 he green shows a normal range.he red ottom let uadrant would indicate right ventricular hypertrophy while the top right would indicate let ventricular hypertrophy. ECG TRANSITION osYns.it/ECG-lransvtion hest leads provide inormation on vector rotation in horizontal plane ° Normal gradual transition o QRS through leads V1-V6 - QRS complex switches rom predominantly negative to positive either etween V2, V3 or etween V3, V4 R WAVE PROGRESSION Early tall R wae in VI, V2 Delayed R; transition point etween V4, 5/etween V5, V6 - R amplitude > S; no progression through V5, V6 Reverse: decreasing amplitude ASSESSMENT FOR NORMAL REGULAR RHYTHM Is there a P eore eery QRS complex? Is there a QRS ater eery P? Are the P waes normal ABNORMAL RATES & RHYTHMS onentionally deined, sinus radycardia 60pm °rue normal adult resting heart rate is 50-0pm inus tachycardia > lOOpm If SA node ails, other latent ectopic pacemaers capale o automaticity ° Atria, AVunction, is undle, undle ranches can set heart rate ° Each oci has uniue rate atrial oci 60-80pmunctional oci 40-60pm ventricular oci 20-40pm ° Overdrive suppression mechanism y which only oci/node with highest iring reuency rate conducts impulses, suppresses other pacemaer sites Heart blocks inus loc ° SA node temporarily ceases to conduct impulse usually resumes, may cause escape rhythm OSMOSIS.ORG 131 10/21/23, 11:43 AM Electrocardiography Notes: Diagrams & Illustrations | Osmosis https://www.osmosis.org/notes/Electrocardiography#page-1 5/8 AV loc = irst degree: prolonged PR interval > 0.2s ° econd degree: some P waes conducted to ventricles,ollowed y QRS complex while some not ° hird degree: atria, ventricles eat asynchronously with no conduction through AV node complete dissociation etween P, QRS complexes) Bundle branch blocks et undle ranch loc (LBBB) ° Activation o let ventricle delayed causing let ventricle to contract later than right ventricle ° road QRS < 120ms ° econdary R wae (R’) in leadsl-3 ° lurred S wae in lateral leads I, avL, V5-6) - econdary repolarization anormalities in right precordial leads (ST depression, T wae inversions) ight undle ranch loc (RBBB) ° Activation o right ventricle delayed causing right ventricle to contract later than let ventricle - road QRS < 120ms ° Dominant S wae in VI ° Asence o Q waes, road monophasic R wae in lateral leads et anterior ascicular loc ° Impulses conducted to let ventricle via let posterior ascicle - et axis deviation ° Increased R wae peatime in a ° mall Q waes, tall R waes in leads 1, a ° mall R waes, deep S waes in leads II, III, a ° Increased QRS voltage in lim leads ° rolonged R wae peatime in a > 45ms et posterior ascicular loc - Impulses conducted to let ventricle via let anterior ascicle ° ight axis deviation ° Increased R wae peatime in a ° mall R waes with deep S waes in leads I, a ° mall Q waes with tall R waes in leads II, III, a ° Increased QRS voltage in lim leads QRS TRANSITION ZONE Figure 18.5 he QRS transition zone usually occurs in the V3 and V4 lead. VI and V2 are mostly positive while V5 and V6 are mostly negative. 132 OSMOSIS.ORG 10/21/23, 11:43 AM Electrocardiography Notes: Diagrams & Illustrations | Osmosis https://www.osmosis.org/notes/Electrocardiography#page-1 6/8 Chapter 18 Cardiovascular hysiology: Electrocardiography ECG CARDIAC HYPERTROPHY & ENLARGEMENT osms.iVCCG-cardiac-hypertropliy-enlargeYneYyt ATRIAL DILATION/ENLARGEMENT iphasic P waes > one small box in lead VI Initial component o wae larger ° ight atrial enlargement erminal component o wae larger ° et atrial enlargement Amplitude o P wae in any lim lead > 2.5mm - roale right atrial enlargement RIGHT VENTRICULAR HYPERTROPHY V1-V6 all consisting o small r waes, deep S waes no R wae transition all R wae in VI that progressiely shortens across to V6 (reverse R wae transition ossile right axis deviation LEFT VENTRICULAR HYPERTROPHY Deep S wae in lead VI all R wae in V5 and/or V6 um o S wae depth in VI + R wae height in either V5/V6 > 35mm ossile let axis deviation et ventricular ‘strain pattern’ ° Downsloping ST segments, T wae inversions in lateral leads Figure 18.6 ypertrophy is an enlargement o the muscle wall while an increase in volume is nown as dilation. r 1 CHARACTERISTICS of CARDIAC HYPERTROPHY LEFT RIGHT ATR1AL ENLARGEMENT VI: Biphasic P, II: Double-Humped II & VI: Big P VENTRICULAR ENLARGEMENT k VI: Big R; V5: Big S VI: Huge S; V5 &V6: Huge R OSMOSIS.ORG 133 10/21/23, 11:43 AM Electrocardiography Notes: Diagrams & Illustrations | Osmosis https://www.osmosis.org/notes/Electrocardiography#page-1 7/8 ECG MYOCARDIAL INFARCTION & ISCHEMIA osmns.it/ECG-cardiac-inlarction-isclieinia MYOCARDIAL INFARCTION omplete/partial locage in coronary artery causing myocardial damage ST elevation Mis EMIs complete artery locage ° ST elevation present on ECG; emergency Non-elevation Mis NEMIs: partial artery locage ° ST elevations not present on ECG ° ess emergent than STEMI ISCHEMIA Inverted T waes slight to deep most pronounced in chest leads Angina transient T wae inversion; may occur without inarction Inverted T wae in any leads V2-V6 are anormal °uggest ischemia,ariety o other pathologies Acute or recent inarction: elevated ST segment slight to extensive) - One o the earliest ECG signs o inarction ° eturns to aseline overtime estricted coronary loodlow:lat depressed ST segment °uggests suendocardial inarction any ST depression NECROSIS athologic Q wae > 0.04s, amplitude < % - Amm the R wae height ° Non-pathological q waes < 0.04s considered normal Ignore AVR lead record leads with Q pathological, q physiological waes ST depression/elevation; inverted T waes Anterior let ventricular inarction (q in V5, V6) ° hest leads anterior location Q waes in leads VI, V2, V3 /V4 osterior inarction ° arge R in leads VI, V2; possile Q in V6 ° Mirror test: invert, examine relection or vQ, ST elevation in leads VI, V2 ateral inarction: Q in leads I, AVL • Inerior inarction: Q in leads II, III, AVF (OSM0SIS.org 2023 Edition 134 OSMOSIS.ORG 10/21/23, 11:43 AM Electrocardiography Notes: Diagrams & Illustrations | Osmosis https://www.osmosis.org/notes/Electrocardiography#page-1 8/8 Chapter 18 Cardiovascular hysiology: Electrocardiography ECG CHARACTERISTICS of COMMON ARRHYTHMIAS ISCHEMIA INFARCTION SUBENDOCARDIAL tale angina ST Depressions nstale angina NSTEMI; ST Depresssions T wae Inversion TRANSMURAL nstale angina NSTEMI; ST Depresssions T wae Inversion STEMI; T wae inversions; yperacute T waes ST elevation; athologic Q waes OSM0SIS.org OSMOSIS.ORG 135