Syncope and the risk of sudden cardiac death: Evaluation, management, and prevention

Abstract

Syncope is a clinical syndrome defined as a relatively brief self-limited transient loss of consciousness (TLOC) caused by a period of inadequate cerebral nutrient flow. Most often the trigger is an abrupt drop of systemic blood pressure. True syncope must be distinguished from other common non-syncope conditions in which real or apparent TLOC may occur such as seizures, concussions, or accidental falls. The causes of syncope are diverse, but in most instances, are relatively benign (e.g., reflex and orthostatic faints) with the main risks being accidents and/or injury. However, in some instances, syncope may be due to more worrisome conditions (particularly those associated with cardiac structural disease or channelopathies); in such circumstances, syncope may be an indicator of increased morbidity and mortality risk, including sudden cardiac death (SCD). Establishing an accurate basis for the etiology of syncope is crucial in order to initiate effective therapy. In this review, we focus primarily on the causes of syncope that are associated with increased SCD risk (i.e., sudden arrhythmic cardiac death), and the management of these patients. In addition, we discuss the limitations of our understanding of SCD in relation to syncope, and propose future studies that may ultimately address how to improve outcomes of syncope patients and reduce SCD risk.

Screening Pediatric Patients in New-Onset Syncope (SPINS) Study

“…There was a considerable prognostic difference between syncope during "full flight," which has a very worrisome mortality risk (ie, true exertional syncope), compared with the lesser mortality concern associated with events occurring either after completion of exertion (ie, post-exertional) or at rest (ie, non-exertional). [41][42][43] For this reason, we still advocate to obtain an EKG, in patient with syncope without a prodrome or with exercise, even with these results not being statistically significant.…”

Early Proteome Shift and Serum Bioactivity Precede Diesel Exhaust-induced Impairment of Cardiovascular Recovery in Spontaneously Hypertensive Rats

“…e . postexertional hypotension), often manifesting as syncope, is linked to increased risk for cardiac events 26 . Additionally, the absence of a reflex increase in heart rate in response to postexertional hypotension suggests impairment of arterial baroreflex control of heart rate 27 .…”

Risk stratification of sudden cardiac death in heart failure patients: is left ventricular ejection fraction alone sufficient?

“…В связи с этим многие эксперты призывают искать дополнительные факторы риска для определения показаний к имплантации КД в огромной когорте пациентов с ФВ ЛЖ <35%, особенно, в случае неишемического генеза СН [7]. Обсуждаются значимость верификации генетической природы болезни [8], наличие семейного анамнеза ВСС [9], обмороков неясного генеза [10], неустойчивой желудочковой тахикардии (ЖТ) [11], отсроченного накопления контрастного препарата в миокарде по данным магнитно-резонансной томографии (МРТ) [12] и др. Имеющиеся данные неоспоримо указывают на то, что для реализации аритмогенного сценария ВСС требуются определенные предпосылки -некий субстрат, на выявление которого должна быть ориентирована любая методика, ставящая целью стратификацию риска ВСС [3].…”