ECG, Medical, ECG Changes in STEMI

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ECG is the mainstay of diagnosing STEMI which is a true medical emergency
Making the correct diagnosis promptly is life-saving. That is why when a clinical picture correlates with MI, ECG becomes the first line of Investigation. 

What is Acute Coronary Syndrome

 Coronary heart disease is a major cause of death and disability in developed countries and the world
•Unstable coronary disease (ACS) is characterized by plaque rupture or erosion with associated thrombosis
–STEMI
–NSTEMI
–Unstable angina
•STEMI is a true medical emergency

ECG in STEMI
•ECG is a mainstay in the initial diagnosis of patients with suspected ACS which will dictate management
•In patients with acute STEMI the ECG evolves through a typical sequence

•Definition of STEMI
–New ST elevation at the J point in two contiguous leads of >0.1 mV in all leads other than leads V2-V3
–For leads V2-V3 the following cut points apply: ≥0.2 mV in men ≥40 years, ≥0.25 mV in men <40 years, or ≥0.15 mV in women
•Other conditions which are treated as a STEMI
–New or presumed new LBBB
–Isolated posterior MI
•The presence of reciprocal ST depression helps confirm the diagnosis

 

Examples of ECG Changes in STEMI:

 

 

What are contiguous leads?

Contiguous leads are “next” to one another anatomically speaking. They view the same general area of the heart (specifically the left ventricle).The “inferior” leads (II, III and aVF) view the inferior wall of the left ventricle. Remember that the inerior leads make up the lower-left corner of the 12 lead ECG.The “septal” leads (V1 and V2) view the septal wall of the left ventricle. They are sometimes grouped together with the anterior leads.The “anterior” leads (V3 and V4) view the anterior wall of the left ventricle.The “lateral” leads (I, aVL, V5 and V6) view the lateral wall of the left ventricle. Leads I and aVL are sometimes referred to as the “high lateral” leads, because their positive electrode is on the left shoulder. Leads V5 and V6 are sometimes referred to as the “low lateral” leads because their positive electrodes are on the lateral left chest.