Ischemia

AbstractThe word “ischemia” refers to a situation in which the blood flow is insufficient to meet the metabolic demands of a tissue or an organ. Ischemia is caused by the total or partial occlusion of an artery. It can create a life‐threatening situation, and the vascular diseases related to ischemia are among the first causes of mortality and morbidity in the world. In its acute form, ischemia is usually originated by the rupture of a vulnerable atherosclerotic plaque, by the lodge of an embolus in an artery, or less frequently, by an artery spasm. On the contrary, chronic ischemia is related to stable atherosclerotic plaques that narrow the artery lumen.Ischemia can affect different organs or tissues, but its most harmful (and frequent) forms are myocardial and cerebral ischemia. Limb, mesenteric, and renal ischemia are also clinically significant. Different techniques are used to diagnose ischemia, including analysis of bioelectric signals (electrocardiogram), ultrasonic techniques (ultrasonography and doppler‐echography), angiography, magnetic resonance imaging (MRI ), or computerized axial tomography (CAT scan). In the treatment of ischemia, percutaneous interventions (angioplasty), together with stent placement, are used in addition to surgery and pharmacological therapies.Acute myocardial ischemia is a life‐threatening form of ischemia. It causes different metabolic alterations that lead to changes in ionic concentrations, action potentials, and overall electrical activity of the heart, setting the stage for malignant arrhythmias to occur (e.g., ventricular fibrillation) and posing a critical threat on the life of the patient.