Señor

Syncope
David G. Benditt, MD, J. Gert Van Dijk, MD, PhD, Richard Sutton, DscMed, Wouter Wieling, MD, PhD, Joseph C. Lin, MD, Scott Sakaguchi, MD, and Fei Lu, MD, PhD
Abstract: Syncope is a syndrome consisting of a relatively short period of temporary and self-limited loss of consciousness caused by transient diminution of blood flow to the brain (most often the result of systemic hypotension).Syncope comprises part of a subset of clinical conditions in which loss of consciousness is transient. Other conditions in this group, which are not syncope and should be clearly distinguished from syncope, include, for example, seizure disorders, posttraumatic loss of consciousness, and cataplexy. Recent surveys indicate that syncope accounts for approximately 1% of emergency department visits inEurope, although older reports from the United States placed this number closer to 3%. The reported prevalence of syncope in the population varies: 15% of children before the age of 18 years; 25% of a military population aged 17 to 26 years; 16% and 19%, respectively, in men and women aged 40 to 59 years; and up to 23% in a nursing home population older than 70 years. The highest frequency ofsyncope occurs in patients with cardiovascular comorbidity and older patients in institutional care settings. The causes of syncope are numerous and, not infrequently, multiple factors may contribute. The diagnostic evaluation is benefited by availability of a detailed medical history and reports of eyewitnesses. In this context, the physician must consider the classification of the causes of syncope,and
Dr Benditt is a shareholder and consultant for Medtronic Inc and St. Jude Medical, and is a shareholder in Cardionet Inc. Dr Sutton is a consultant to Medtronic Inc. Drs van Dijk, Wieling, Lin, Sakaguchi, and Lu have no conflicts of interest to disclose. 0146-2806/$ – see front matter doi:10.1016/j.cpcardiol.2003.12.002

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Curr Probl Cardiol, April 2004

address the most likely causesfirst. The principal groups of causes may be summarized as: (1) neurally mediated reflex syncope (eg, vasovagal faint, carotid sinus syndrome); (2) orthostatic (postural) syncope; (3) cardiac arrhythmias; (4) structural cardiac and pulmonary causes; and (5) cerebrovascular disorders (rare). In addition, conditions that may mimic syncope but are not true syncope (eg, psychogenic pseudosyncope) mustbe considered. Only after a definitive cause is established can appropriate treatment be initiated. In this regard, the syncope evaluation is facilitated by maintaining an organized diagnostic approach. The practitioner should avoid wasteful use of short-term ambulatory electrocardigraphic recordings (eg, Holter monitors) and rarely positive neurologic tests (eg, electroencephelography, headmagnetic resonance imaging/computed tomography) in the absence of head trauma or evident neurologic signs. In many medical centers the evaluation of patients with syncope is haphazard, and may be substantially enhanced by establishment of a multidisciplinary syncope evaluation unit or team. (Curr Probl Cardiol 2004;29: 145-229.) yncope is a syndrome consisting of a relatively short period of temporaryand self-limited loss of consciousness caused by transient diminution of blood flow to the brain (most often the result of systemic hypotension).1,2 Synonyms for syncope include “fainting,” “blacking out,” and “passing out.” In some cases individuals will report symptoms that suggest a near faint, but complete loss of consciousness does not occur. Often these events are termed “gray outs,” “nearsyncope,” or “presyncope.” On the other hand, many patients have less specific symptoms such as dizziness or lightheadedness. More often than not, these latter symptoms are not related to syncope either clinically or pathophysiologically. Table 1 provides a diagnostic classification of the most important causes of syncope. Syncope falls within a larger category of clinical conditions that cause loss...