Syncope

Syncope is a syndrome in which a relatively brief and self-limited period of loss of consciousness is triggered by transient insufficiency of oxygen delivery to the brain; most often, spontaneously reversible systemic hypotension leading to insufficient cerebral blood flow is at fault. Syncope falls within a larger set of conditions in which there is real or apparent transient loss of consciousness (TLOC). However, not all TLOC is syncope. Thus, a TLOC episode should not be considered syncope if a medical intervention is required to reverse the loss of consciousness. Similarly, if cerebral dysfunction is not due to insufficient cerebral nutrient flow, the loss of consciousness or apparent loss of consciousness should not be termed syncope. Finally, many patients complain of less-specific symptoms such as dizziness or lightheadedness. Most often, these latter symptoms are not related to syncope either clinically or pathophysiologically but nevertheless often find their way into the syncope clinic and require evaluation. A wide range of conditions may be responsible for initiating syncope. In any case, whether the underlying problem is innocent or potentially life-threatening, syncope may lead to physical injury, accidents that put the affected individual and others at risk, and economic loss. The physician's key tasks are to establish a confident causal diagnosis and provide appropriate advice regarding treatment and prognosis. To be successful, it is important to develop an organized approach to the assessment of the syncope patient. The initial patient evaluation, particularly a detailed medical history, is crucial. Subsequently, carefully selected diagnostic tests can be chosen to confirm the clinical suspicion. This chapter focuses on clinical management (diagnosis and treatment) of syncope. Whenever possible, the recommendations provided here are adapted from the European Society of Cardiology Syncope Task Force guidelines.