acute myocardial infarction (redirected from Shoulder pain)

infarction /in·farc·tion/ (in-fahrk´shun)

1. the formation of an infarct.

2. infarct.

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acute myocardial infarction  (AMI) that occurring during the period when circulation to a region of the heart is obstructed and necrosis is occurring.

cardiac infarction  myocardial i.

cerebral infarction  an ischemic condition of the brain, causing a persistent focal neurologic deficit in the area affected.

mesenteric infarction  coagulation necrosis of the intestines due to a decrease in blood flow in the mesenteric vasculature.

migrainous infarction  a focal neurologic defect that constituted part of a migrainous aura but that has persisted for a long period and may be permanent.

myocardial infarction  (MI) gross necrosis of the myocardium, due to interruption of the blood supply to the area.

Myocardial infarction shown in cross-section of heart (ventricles only).

non–Q wave infarction  myocardial infarction not characterized by abnormal Q waves.

pulmonary infarction  localized necrosis of lung tissue, due to obstruction of the arterial blood supply.

Q wave infarction  myocardial infarction characterized by Q waves that are abnormal either in character or number or both.

silent myocardial infarction  myocardial infarction occurring without pain or other symptoms; often detected only by electrographic or postmortem examination.

watershed infarction  cerebral infarction in a watershed area during a time of prolonged systemic hypotension.

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acute myocardial infarction (AMI)

Etymology: L, acutus, + Gk, mys, muscle, kardia, heart; L, infarcire, to stuff

the early critical stage of necrosis of heart muscle tissue caused by blockage of a coronary artery. It is characterized by elevated S-T segments in the reflecting leads and elevated levels of cardiac enzymes. See also myocardial infarction.

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acute myocardial infarction (·kyōōtˑ mī·ō·karˑ·dē·l in·farkˑ·shn),

n early stage of heart muscle mortification caused by blockage in a coronary artery.

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acute myocardial infarction

Cardiology The abrupt death of heart muscle due to acute occlusion or spasm of the coronary arteries Epidemiology ±1.5 million MIs/yr–US, 75,000 AMI follow strenuous physical activity, of whom¹⁄₃ die; ±¹⁄₄ of all deaths in the US are due to AMIs; > 60% of the AMI-related deaths occur within 1 hr of the event; most are due to arrhythmias, in particular ventricular fibrillation Triggers Heavy exertion in ±5% of Pts, which is inversely related to Pt's habitual physical activity Etiology Occlusion of major coronary artery–CA, in a background of ASHD, due primarily to the plugging of the vessel with debris from an unstable plaque–see Uncomplicated plaque Clinical Main presenting symptom–retrosternal chest pain accompanied by tightness, discomfort, & SOB; cardiac pain often radiates to the arm & neck, and less commonly to the jaw; the pain of AMI generally is not relieved with nitroglycerin, in contrast to esophageal pain, which is often identical in presentation, and may respond, albeit slowly, to nitroglycerin; the characteristic clinical picture notwithstanding, there is a high rate of false negative diagnoses of AMIs Diagnosis Clinical presentation, physical examination, EKG–sensitivity in diagnosing AMI is 50–70%, and is lower in lateral MIs than in anterior and inferior MIs; CXR may demonstrate left ventricular failure, cardiomegaly Echocardiography M-mode, 2-D & Doppler Radioisotopic studies Radionuclide angiography, perfusion scintigraphy, infarct-avid scintigraphy, & PET can be used to detect an AMI, determine size & effects on ventricular function, and establish prognosis; a radiopharmaceutical, 99mTc-sestamibi, has become the perfusion imaging agent of choice, given its usefulness for measuring the area of the myocardium at risk for AMI, and for recognizing the myocardium salvaged after thrombolytic therapy Other imaging techniques–eg, CT, and MRI Lab CK-MB, troponin I DiffDx AMI is the most common cause of acute chest pain in older adults, other conditions must be excluded–Prevention ↓ Smoking, ↓ cholesterol, ↓ HTN; ↑ aerobic exercise; influence of other factors-eg maintaining normal body weight, euglycemic state in diabetes, estrogen-replacement therapy, mild-to-moderate alcohol consumption, effect of prophylactic low-dose aspirin-on incidence of AMI is less clear. See AIMS, ASSET, EMERAS, EMIP, GISSI, GISSI-2, GUSTO-1, INJECT, ISIS-2, ISIS-3, LATE, MITI-1, MITI-2, RAPID, TAMI-5, TAMI-7, TEAM-2, TIMI-2, TIMI-4, Trial

Differential diagnosis of acute myocardial infarction

Arm pain

Myocardial ischemia, cervical/thoracic vertebral pain, thoracic outlet syndrome

Epigastric pain

Myocardial ischemia, GI tract–esophagus, peptic ulcers, pancreas, liver disease–cholecystitis, hepatic distension, pericardial pain, pneumonia

Retrosternal pain

Myocardial ischemia, aortic dissection, esophageal pain, mediastinal lesions, pericardial pain, PTE

Shoulder pain

Myocardial ischemia, cervical vertebra, acute musculoskeletal lesions, pericardial pain, pleuritis, subdiaphragmatic abscess, thoracic outlet syndrome

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