12Einthoven’s Triangle Lead I - + Lead III Lead II extends from the right to the left armLead IIIextends from the left arm to the left footLead IIextends from the right arm to the left foot
13Diagnosing MITo diagnose a myocardial infarction you need to go beyond looking at a rhythm strip and obtain a 12-Lead ECG.12-Lead ECGRhythm Strip
14The 12-Lead ECGThe 12-Lead ECG sees the heart from 12 different views.Therefore, the 12-Lead ECG helps you see what is happening in different portions of the heart.The rhythm strip is only 1 of these 12 views.
20ST Elevation (cont)Elevation of the ST segment (greater than 1 small box) in 2 leads is consistent with a myocardial infarction.
21Left Main Coronary Artery Branches quickly into the LAD & LCX. Involves almost 2/3 of the heart muscle primarily anteriorRight Coronary Artery (RCA) The RCA supplies blood to the bottom (inferior) portion and part of the back (posterior) portion of the left ventricle The posterior portion of the septum is also supplied with blood from the RCA.SA Node 55%AV Node 90%AV BlocksLeft Anterior Descending Branch (LAD) The LAD supplies blood to the front (anterior) portion of the left ventricle, apical including most of the anterior portion of the septum separating the ventricles.Bundle Branch Block, AMI, CHFLeft Circumflux Branch (LCX) The LCX supplies blood to the left side (lateral) portion and the back (posterior) portion of the left ventricle.SA Node 45%AV Node 10%Lateral & posterior MI
22MI Locations Lateral portion of the heart Anterior portion of the heartLateral portion of the heartInferior portion of the heartLook again at this picture of the heart.
23MI Locations Lateral portion of the heart Anterior portion of the heartLateral portion of the heartInferior portion of the heartLook again at this picture of the heart.
24Anterior View of the Heart The anterior portion of the heart is best viewed using leads V1- V4.
25Anterior MIRemember the anterior portion of the heart is best viewed using leads V1- V4.Limb LeadsAugmented LeadsPrecordial Leads
26View of Anterior Heart Wall Anterior Wall MIView of Anterior Heart WallLeads V3, V4Looks at anterior heart wallLooks from the left anterior chest
27Lateral MISo what leads do you think the lateral portion of the heart is best viewed?Leads I, aVL, and V5- V6Limb LeadsAugmented LeadsPrecordial Leads
28View of Lateral Heart Wall Lateral Wall MIView of Lateral Heart WallLeads I and aVLLooks at lateral heart wallLooks from the left arm toward heart*Sometimes known as High Lateral*
29Inferior MI Now how about the inferior portion of the heart? Leads II, III and aVFLimb LeadsAugmented LeadsPrecordial Leads
30View of Inferior Heart Wall Inferior Wall MIView of Inferior Heart WallLeads II, III, aVFLooks at inferior heart wallLooks from the left leg up
31Putting it all Together Now, where do you think this person is having a myocardial infarction?
32Inferior Wall MIThis is an inferior MI. Note the ST elevation in leads II, III and aVF.
33Inferior Wall MIThis is an inferior MI. Note the ST elevation in leads II, III and aVF.