Presentation on theme: "Leads, Leads and More Leads…."— Presentation transcript:
1 Leads, Leads and More Leads…. The question is..where does this all “lead” us?Silver Cross EMS Continuing Education1st Trimester January 2013By Laurie Carroll, RN, Adventist Bolingbrook HospitalSilver Cross EMS Education Staff.
2 Our Agenda Today System announcements Cardiac anatomy and physiology EKG review (ALS)12-lead review (ALS)Mini-CME: Autism
3 Silver Cross EMSS announcements New 1st Quarter Region 7 QA – 12 lead use.Consider 12-leads for:Chest/arm/jaw/back pain (non-trauma)Unexplained diaphoresisVomiting w/o fever or diarrheaSOB/dizzy/syncope/weakness/fatigueEpigastric pain (non-trauma)Unexplained fall in elderlyUnexplained brady/tachyAnd document your decision to use/not use
5 The Heart Four chambers Hollow Muscular Dual Circulation feeds the heart muscle itselfcirculates blood outside the heartlungs for oxygenation and CO2 offloadperipheral supply to tissues, organs and organ systems
6 Right Heart Receives unoxygenated blood from Blood passes from systemic circulationvena cavaecoronary circulationcoronary sinusBlood passes fromright atriumthrough tricuspid valveright ventriclepulmonic valvepulmonary arteryto lungs
7 Left Heart Receives oxygenated blood from pulmonary vein Blood passes fromleft atriummitral valveleft ventricleaortic valveaorta
8 Aorta Oxygenated blood in the aortic root enters the coronary arteries Most myocardial blood supply occurs during diastolethe aortic valve leaflets are closed and do not obstruct the coronary artery rootsthe subendocardial blood vessels are not compressed (as they are during systole) allowing blood to flow into the myocardium itselfin the normal cardiac cycle, diastole is longer than systole
10 Coronary Artery Disease Any narrowing of the coronary arteries causesdiminished blood supplyrestriction of delivery of electrolytes and nutrients
11 to help us understand which areas of the heart are affected Who Supplies What?It is often helpful to understand where the supply of blood is coming from,to help us understand whichareas of the heart are affectedby various strictures/occlusions.
12 LCA Left Left main divides into two branches Left Anterior Descending (LAD)Anterior wall of LVRBB and portions of LBBAssociated with Anterior Wall MICircumflex (Cx)Lateral and Posterior walls of LVLeft atriumSA node in ~ 30%Associated with Lateral Wall MI
13 RCA Right Right Atrium (RA) Right Ventricle (RV) Inferior and Posterior LVSA node in ~60%AV nodeAssociated withright ventricular MIordysrhythmias affectingSA and AV nodes
14 Area of InjuryInfarct =dead or necrosisBlockage =causes ischemia
15 Collateral Circulation If coronary artery disease and stenosis develop slowly, collateral circulation can developWhen the stenosis is acute, collateral circulation does not have time to develop
17 Cardiac Rhythm Disturbances CO (cardiac output) =HR (heart rate) x SV (stroke volume)Rhythm disturbances can hamper delivery of blood to the myocardium
18 Normal ECG Review P wave P-R Interval QRS S-T Segment T wave Smooth, rounded, uprightP-R IntervalsecondsQRSSymmetrical< .10 secondsS-T SegmentIsoelectricT waveUpright, rounded
19 Where do the stickies go, and why? Hook ‘em up:Where do the stickies go, and why?A lead is a record of electrical activity between two electrodes. Each lead records the average current flow at a specific time in a portion of the heart.Skin preparation:dry, hair-freePlacing the electrode. Be sure that the electrode has adequate gel and is not dry.
20 Trouble shooting EKG Clarity Equipment Grounded?Cables attached?Patient in reclining or semi fowler position?Patient sitting still?Skin clean and dry?Limb leads in place or reversed?
21 There are three kinds of leads: Standard Limb LeadsAugmented LeadsPrecordial Leads
22 (Remember: “lead” may refer to a direction, or placement.) Standard Limb Leads(Remember: “lead” may refer to a direction, or placement.)Lead I: The positive lead is above the left breast or on the left arm and the negative lead is on the right arm. Records the difference of potential between the Left arm and Right arm.Lead II: The postive lead is on the left abdomen or left thigh and the negative lead is also on the right arm. Records the difference of potential between the left leg and the right arm.Lead III: The postive lead is also on the left abdomen or left lower lateral leg but the negative lead is on the left arm. Records the difference of potential between the left leg and the right arm.
23 Augmented LeadsThe four limb leads go on the four extremities as follows:The upper extremities need placement of the electrodeson the area of the lateral humoral aspect of the arms.The lower extremities need placement of the electrodeson the lateral lower legs near the lateral mallelous.Lead aVR faces the heart from the right shoulder and is oriented to the cavity of the heart.Lead aVL faces the heart from the left shoulder and is oriented to the Left Ventricle.Lead aVF face the heart from the left hip and is oriented to the inferior surface of the Left Ventricle.
24 Precordial Lead Placement v1 - 4th ICS, R sternal borderv2 - 4th ICS, L sternal borderv3 - midway between v2 & v4v4 - 5th ICS, L MCLv5 - 5th ICS, between v4 & v6v6 - 5th ICS, L mid-axillary lineTipSome find it easier to putthe leads on in this order v1, v2, v4, v6Then v3 and v5
25 You Lookin’ at Me?It is important to look at contiguous leads to determine which area of the heart is affected. Each lead is like a camera lens that “looks” at an area of the heart.
26 And how do I know if I have the leads in the right place? If everything in Lead I (P, QRS & T wave) is inverted, RA and RL are reversed.Watch for the progression of the R wave in the precordial leads.“R” WAVE PROGRESSIONThe right ventricle depolarizes faster than the left ventricle because it is smaller.The left ventricle sits to the left and posterior to the right ventricle.As current spreads leftward through the left ventricle, the height of the R wave in the precordial leads progressively increases.Normally, in V1 the R wave is more negative and as it progress to V6 the R wave becomes more positively deflected.“R” wave progression indicates that current is flowing normally through the anterior plane of the heart. (Conover)
27 ECG PatternsAs contiguous leads look at different parts of the heart, you may see an ischemic pattern that covers a large area or border area between two regions.For example, if there is ST-segment elevation in leads II/III/aVF/V5/V6, the ischemia appears to be on both the inferior and lateral areas, referred to as inferolateral.Likewise, there are anterolateral and anteroseptal (like the illustration here) ischemic patterns.What is an ischemic pattern? The AHA cites “typical ST-segment elevation” as “> 1 mm in 2 or more contiguous leads”
28 Injury=Elevated ST segment Signifies an acute process; ST returns to baseline with timeLocation of injury can be determined in samemanner as infarct locationUsually associated with reciprocal ST depressionin other leadsIf ST elevation is diffuse and unassociatedwith Q waves or reciprocal ST depression,consider pericarditis
39 Lateral Infarction ST elevation with/without abnormal Q wave. May be a component of a multiple-site infarctionUsually associated with obstruction of the left circumflex artery.
40 Inferior Wall RCA The most common type of MI Nausea is common Frequent re-infarction or extends to lateral wallSA / AV nodeSB, sinus arrest, HB - 1st or 2nd degree AV blocks, PVC’sNitrates if BP stableMedical control may ask crew to hold nitro for inferior wall MI until right sided infarct is ruled out.
45 Inferior Infarction ST elevation with/without abnormal Q wave Usually associated with right coronary artery(RCA) occlusion
46 Right Ventricular MI Rare RCA LAD or Left circumflex could also cause Right sided heart failureFluids – JVD with hypotensionWatch for inferior wall MI too!
47 Right Ventricular Infarction Usually accompanies inferior MI due to proximalocclusion of the RCABest diagnosed ST elevation in lead V4RAn important cause of hypotension in inferior MI recognized by jugular venous distension with clear lung fieldsAggressive therapy is indicated including:reperfusion, adequate IV fluids for right heart filling, andpacing to maintain A-V synchrony
48 Posterior WallRCALeft CircumflexSeen with Inferior or lateral wall
49 Posterior Infarction Tall, broad (>0.04 sec) R wave and ST depression in V1 and V2 (reciprocal changes)Frequently associated with inferior MIUsually associated with obstruction ofRCA and or left circumflex coronary artery
51 Reciprocal Changes Region of ST Elevation Region of ST Depression Anterior (leads V1-V4)Inferior (true posterior)Inferior (leads II, III, aVF)Anterior (leads V1-V3 or lateral lead 1. aVL)Lateral ( leads I, aVF, V5, V6)Inferior ( leads II, III, aVF)True PosteriorAnterior (leads V1-V3)
52 Making the accurate Field Diagnosis: There are elevations (1 mm) in two contiguous or connecting leads:(Leads adjacent to each other)There is at least one lead with reciprocal changes..Reminder:ECG would have changes in the area where the heart is being affected.All other areas would look normal, without elevation or depression unless there is an "old MI."In that case, the prior damage would show up as a depressed segment.
53 Treat The Patient… Not The Monitor If the patient’s symptoms do not match the ECG, you need to do more detective workECG is “nondiagnostic” in ~ 50% of patients with chest discomfort
75 Mini-CME: AutismMany patients we encounter in EMS have some form of autism or fall somewhere on the autism spectrum of disorders.This month, please register for and complete the course Autism 101, found at:Submit the completion certificate to your EMS coordinator (or Silver Cross EMSS Operations if you are an independent provider).
76 Thank you!Any further questions? If you are viewing the live presentation, please feel free to type them in the message box now.Otherwise, feel free to call or the EMS office or visit our website, ww.silvercrossems.com.