In this lesson, we are going to perform the third and fourth steps of the six step method.
In this lesson, we will learn a few more pathologies which can be identified on a 12-lead ECG. All of these conditions listed can be identified by examining the intervals and morphologies. Lets learn how.
When looking for ST-elevation that indicates an MI, we look for changes in contiguous or associated leads. Contiguous leads look at the same area of the heart muscle.
14 ischemia injury & infarct1
12-LeadElectrocardiography a comprehensive course ia, Is chem I nju ry, & Inf arct (Pa r t 1) Adam Thompson, EMT-P, A.S.
STEMI• STEMI – ST-Segment Elevated Myocardial Infarction – ST-Segment Elevation of > 1mm in two contiguous leads. – In V2 & V3, ST-Segment elevation must be at least 2mm. *The smaller the QRS complex, the more significant minimal ST- Elevation is.
Objectives• Learn how to identify a STEMI• Learn how to localize the infarcted area• Apply everything learned thus far
What are Contiguous Leads?Lead I aVR V1 V4 • lateral Contiguous leads are leads that look at septal anterior the same area of the heart.Lead II aVL V2 V5 •inferior show up on the 12-lead proximal They high lateral septal low lateral to each other.Lead III aVF V3 V6 inferior inferior anterior low lateral
Coronary CirculationRight Coronary Artery Left Main (RCA) Circumflex (LCx)Left Anterior Descending (LAD)
Coronary Circulation Right Coronary Artery Left Circumflex Artery Left Anterior Descending (RCA) (LCx) (LAD)•Right Atrium •Inferior Wall •Anterior•Inferior Wall •Isolated Right Ventricle •Anteroseptal•Inferior-Right Ventricle •Posterior Wall •Anteroseptal-lateral•Posterior Wall - 15% of population - 85% of population •Anterolateral •Inferolateral •Posterolateral *Nicknamed “Widow-maker”
ST-Elevation• The most common cause of ST- elevation is not myocardial infarction.• Less than 50% of STEMI alerts called by paramedics are actually Acute Coronary Syndrome (ACS) patients
ST-Elevation TP-Segment• ST-Elevation is elevation of the J-Point which causes elevation of the following ST- Segment.• Elevation is defined as anything above the T P isoelectric line.• Find the isoelectric line by locating the TP- Segment.
ST-Elevation• The J-Point is where the QRS complex J-Point and the ST-Segment meet.