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Cardiovascular Emergencies    SAMPLE COURSE
Acute Myocardial Infarction

Acute myocardial infarction (AMI) occurs when oxygenated blood cannot reach the myocardium and muscle tissue dies. It is caused when a coronary artery is completely blocked or occluded.

AMI is caused by the same mechanism as angina except that AMI results in tissue death and is not reversible. Patients with AMI can experience:

  • chest discomfort
  • discomfort in other areas of the upper body
  • shortness of breath
  • diaphoresis, nausea or weakness

+ Elaboration — Physiology of AMI

AMI is a severe form of myocardial ischemia. The blood flow through a coronary artery with atherosclerosis is stopped by a blood clot or spasm. Next, the process of anaerobic metabolism begins that produces lactic acid and carbon dioxide. The accumulation of lactic acid and carbon dioxide causes pain. A sustained reduction in blood flow then causes tissue death.

Other conditions can reduce blood flow and cause myocardial ischemia leading to AMI. These include shock, dysrhythmias and pulmonary embolism. All prevent oxygen from reaching the heart muscle.

+ Elaboration Symptoms of AMI

Chest discomfort is one possible symptom of AMI. The discomfort can occur in the center of the chest that lasts more than a few minutes. It can go away and come back. The discomfort can feel like fullness, pressure, squeezing or pain.

Another symptom can be discomfort in other areas of the upper body including pain or discomfort in one or both arms, the back, neck, jaw or stomach.

Shortness of breath is another possible symptom of AMI. Shortness of breath can occur with or without chest discomfort.

Other associated symptoms can include dyspnea, nausea, vomiting, diaphoresis, dizziness and a feeling of impending death.

Symptoms of AMI
 
 
Onset varies, can be sudden
Provocation varies, can start at rest
Quality pressure or squeezing pain
Radiation pain can radiate to jaw or arm
Relief none, not relieved with rest and/or nitro
Severity very severe, intense, terrifying (10/10)
Time can last hours

 


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