What is myocardial ischemia?

Updated: Aug 07, 2019
  • Author: Thomas F Heston, MD, FAAFP, FASNC, FACNM; Chief Editor: Eugene C Lin, MD  more...
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Myocardial ischemia is a disorder that is usually caused by a critical coronary artery obstruction, which is also known as atherosclerotic coronary artery disease (CAD). CAD is the leading cause of death worldwide, and it is the second most common cause of emergency department visits in the United States. Diagnosing myocardial ischemia prior to a heart attack is important. For approximately one third of patients, CAD is not diagnosed until after a heart attack occurs. Fortunately, treating known CAD has tremendous benefits. Both coronary artery revascularization and medical therapies significantly reduce the morbidity and mortality rates of CAD. Since CAD is common and deadly, but treatable if detected early, early diagnosis of the condition is critical.

When ischemia is severe and prolonged, it causes myocyte death and results in loss of contractile function and tissue infarction. In cases of less severe ischemia, some myocytes remain viable but have depressed contractile function. The disease occurs in both the young and the old, in both women and men, and in both patients with and patients without comorbidities.

The diagnosis of CAD can be difficult to make. Frequently, the disease is diagnosed only after the patient has had a heart attack. The symptoms of CAD range from unstable angina to no symptoms at all. Although guidelines exist for the screening of hyperlipidemia and hypertension, no screening method has been uniformly accepted for CAD. 

Several studies have been designed to help the clinician determine a patient’s CAD risk level. [1, 2] With this information, the clinician can decide, with reasonable certainty, which type of workup is indicated. For the low-risk population, exercise treadmill testing alone is frequently sufficient; however, in patients with a moderate-to-high risk for CAD, an imaging study is essential along with the stress test. [3, 4, 5]

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