the property possessed by some substances of rotating the plane of polarization of polarized light. A compound that rotates the plane to the left is described as laevorotatory (or l-); one that rotates the plane to the right is described as dextrorotatory (or d-).
(OCT) a class of optical tomographic techniques that allows extremely high-quality micrometre-resolution three-dimensional images to be obtained from within optical scattering media (e.g. biological tissue). OCT is proving valuable in ophthalmology, for noninvasive imaging of the ocular structures, and in cardiology for visualizing the interior of coronary arteries using a specialized *catheter. See also spectral domain optical coherence tomography.... optical coherence tomography
(electromechanical dissociation) the appearance of normal-looking complexes on the electrocardiogram that are, however, associated with a state of *cardiac arrest. It is usually caused by large pulmonary emboli (see pulmonary embolism), *cardiac tamponade, tension *pneumothorax, severe disturbance of body salt levels, severe haemorrhage, or hypothermia causing severe lack of oxygen to the heart muscle.... pulseless electrical activity
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