ECGs: Ischemia and Infarction AFAMS Resident Orientation 26 March 2012

Outline

Terminology Injury – Acute MI – ST elevation in 2 contiguous leads – Reciprocal ST depression Ischemia – ST depression, T wave inversion Infarct – Q waves

EKG Stages of MI Hyperacute T waves (A) ST elevation (B) Q waves – usually within 6-12h (C) T wave inversions (D) ST-T wave resolution – Q waves persist European Heart Journal 2007; 28,

EKG Stages of MI Hyperacute T waves

Sinus tachycardia, Inferior MI – recent, Nonspecific ST-T wave changes

NSR, Biatrial Enlargement, Old inferior MI

Localization of MI Anteroseptal – ST elevation in V1-V3 Anterior – ST elevation in V2-V4 Lateral – ST elevation in I, AVL, V5-6 Inferior – ST elevation in II,III,AVF

47 year old male with chest pain NSR with anteroseptal myocardial infarction

65 year old male with chest tightness NSR with acute anterior myocardial infarction

62 year old female with shortness of breath and chest discomfort Sinus Tachycardia with Lateral Myocardial Infarction

45yo wm with 2 hours of SSCP that started during exertion NSR with PVC, LAD, Acute anterolateral MI

Middle age white male awoke from sleep with chest pain Sinus tachycardia, Acute Inferior MI

Right Sided ECG Who? – Any patient with inferior ST elevation MI Why? – Investigate infarct involvement of RV How? – Reverse Precordial Leads Where to Look? – ST elevation in V 4 R

Right Sided EKG

Not all ST changes are ischemia While ischemia and infarction are the most concerning causes of ST changes, other causes exist Use the clinical history to help you Recognize patterns

20 year old asymptomatic male Sinus bradycardia, Early repolarization -> Normal variant

NSR, PACs, LVH – voltage criteria, repolarization abnormality  HCM

59yo female presents to the ER with CP NSR, Acute pericarditis (Diffuse ST elevation and PR depression), and Pericardial effusion (electrical alternans)

26 year old male with syncope NSR, RBBB, Long QT-> Brugada Syndrome

Differential Diagnosis of ST elevation STEMI LV aneurysm Left Ventricular Hypertrophy Pericarditis / Myocarditis Early Repolarization – Normal variant Hyperkalemia Brugada Syndrome ARVD

Examples of ST Elevations NEJM 2003: 349:

Conclusions ST changes often represent ischemia, injury or infarction Many other possible diagnoses Use clinical information to narrow down the list When you are unsure, call a cardiologist