If you prefer to follow along and take notes in a linear fashion, attached here is the outline for you to do so. Scenario: 50 year old male with a history of angina. Admitted 2 hours ago with new onset of chest pain. No relief after 3 Nitro SL. Attached here is an animation from your Lewis Textbook with an overview of Acute Myocardial Infarction. Sources: Lewis, S. (2007). Medical-surgical nursing: Assessment and management of clinical problems (7th ed.). Philadelphia, PA: Mosby Elsevier. Videos: Cardiac Signs & Symptoms (Blanchard & Loeb, 2005,) and Basic Code Management (Mosby, 2007).
A myocardial infarction (MI) occurs as a result of sustained ischemia, causing irreversible mycardial cell death (necrosis). Thrombus formation is responsible for 80% to 90% of all acute MIs. When a thrombus develops, perfusion to the myocardium distal to the occlusion is blocked, resulting in an infarction. See the attached figure that demonstrates the common areas of infarction and the coronary arteries that perfuse these areas. Infarctions are described by the area of occurence, the common ones being anterior, inferior, lateral, or posterior wall infarctions.
Severe, immobilizing, and persistent chest pain not relieved by rest or nitrate administration is the hallmark of an MI. See attached figure demonstrating the location and variety of presentations of chest pain during a myocardial infarction.
A 12-lead EKG is the primary diagnostic tool used to evaluate patients presenting with acute coronary syndrome. Changes in the leads that face the area of involvement are shown in Figure 36-28. Figure 36-29 shows the wave changes associated with myocardial ischemia (A), injury (B), and infarction (C).
Certain proteins, called serum cardiac markers, are released into the blood in large quantities from necrotic heart muscle after an MI. The MB band of creatine kinase (CK-MB) and troponin are two important specific markers that con indicate the presence and extent of cardiac damage.
creatine kinase (CK-MB)
reperfusion therapy, fibrinolytic therapy, tissue plasminogen activator (tPA), streptokinase, reteplase (Retavase), emergent percutaneous coronary intervention (PCI)
systemic anticoagulation, SQ or IV low-molecular-weight heparin
calcium channel blockers
Coronary artery bypass graft surgery (CABG) consists of the construction of new vessels between the aorta or other major arteries and the myocardium distal to the obstructed coronary artery. See attached figure showing a double bypass.
The goal of nursing care is to minimize damage and prevent complications. Standard treatment is easily remembered by the acronym MONA as seen on the attached figure.
premature ventricular contractions
Thromboltyics, TPA, Strepto
When you are done viewing this concept map, take time to read the attached article called “An Eye for MI”. It is a great summary of many of the concepts covered here. Right click on the red speaker icons to hear my audio comments. Also attached is a website called SkillsStat that will help you learn your EKG rhythm strips.