Electrocardiographic manifestations of CNS events

Certain intracranial events produce electrocardiographic abnormalities, mos t often involving the T wave with diffuse, deep inversions. The amplitude o f the T wave inversion is impressive, approaching 15 mm in some cases. Morp hologically, the T wave is asymmetric with a characteristic outward bulge i n the ascending portion. In the setting of a CNS event, relatively minor de grees of ST segment elevation are also seen in leads with obviously abnorma l T waves; the ST segment elevation frequently is less noticeable than the T wave changes and is usually less than 3 mm, The T wave inversions with as sociated ST segment elevation are most pronounced in the mid-precordial and lateral precordial leads; such findings are also noted to a less extent in the limb leads. Other electrocardiographic features associated with acute CNS injury include prominent U waves of either polarity and QT interval pro longation, often exceeding 60% of its normal value, as well as malignant fo rms of bradycardia and tachycardia, (Am J Emerg Med 2000;18:715-720. Copyri ght (C) 2000 by W.B. Saunders Company).