Transient Cerebral Ischemia and Mitral-Valve Prolapse

Episodes of transient cerebral ischemia, however they may be manifested, usually denote disease of the arteries that supply the brain. A frequent mechanism entails the presence of an atherosclerotic plaque in a carotid artery. From time to time, a bit of atheromatous material or overlying thrombus breaks loose and lodges in a distal branch, thereby causing the patient to have dizziness, to appear befuddled, or to have evidence of some kind of neurologic deficit. When collateral circulation is adequate to the site of cerebral insult, as it must be for an attack to be transient, the symptoms or signs soon disappear, only to recur in like or different form when another embolus dislodges. A similar pattern results in the absence of embolism when a carotid or a vertebral artery¹ is partly occluded for any reason and another hemodynamic factor (eg, cardiac arrhythmia) aggravates already diminished cerebral arterial flow. In