Syncope During Pregnancy

Physiologic changes

“…The resultant vigorous cardiac contraction in volume-depleted chambers stimulates cardiac mechanoreceptors or C-fibers which, in susceptible individuals, can result in paradoxical stimulation of the dorsal vagal nucleus. This stimulation is paradoxical because, in the face of low SVR and cardiac output, there is a further decrease in sympathetic tone and an increase in vagal tone causing vasodilation and bradycardia and the clinical presentation of presyncope or syncope (7). The reflex may be initiated by emotional stimuli in some individuals or may be initiated by compression of the inferior vena cava by the gravid uterus causing a decrease in venous return and intracardiac pressure.…”

“…Syncope is defined as a transient loss of consciousness and posture, caused by decreased cerebral perfusion that may result from hypotension, changes in heart rate, or changes in blood volume or redistribution. The decreased SVR of pregnancy makes pregnant women particularly susceptible to this condition, with 28.2% of gravidas experiencing at least one episode of presyncope, 10% experiencing recurrent presyncopal episodes, and 4.6% experiencing outright syncope (7). The overwhelming majority of syncopal episodes are benign neurocardiogenic syncope but there are also several potentially dangerous conditions in the differential diagnosis of syncope.…”

“…The reflex may be initiated by emotional stimuli in some individuals or may be initiated by compression of the inferior vena cava by the gravid uterus causing a decrease in venous return and intracardiac pressure. Less common conditions that may present with symptoms of syncope include cerebrovascular accidents, seizures, cardiac arrhythmias or valvular disease, cardiomyopathy, pericardial tamponade, myocardial infarction, congenital heart defects, thromboembolic phenomenon, anemia, hypoglycemia, or electrolyte disorders (7). Further evaluation for such conditions should be prompted when an apparent syncopal episode is accompanied by focal neurologic findings, prolonged loss of consciousness or postictal confusion, carotid or subclavian bruits, a pathologic cardiac murmur, or electrocardiogram (EKG) or laboratory abnormalities (7).…”

Ergonomics in the Unit: Modeling the Environment Around the Endoscopist

“…Syncope and presyncopal episodes can occur in pregnancy as a result of vasodilation and venous pooling [43]. It is particularly common in the first trimester due to hormonal changes and may be associated with adverse pregnancy outcomes [44].…”

Abordaje del diagnóstico y tratamiento oportuno del síncope durante el embarazo.

“…Existe un ajuste en los niveles sanguíneos de hormonas sexuales durante el embarazo lo que puede ejercer un efecto proarritmogénico en el tejido miocárdico (10,11,12). Adicionalmente, se presenta un incremento en la descarga simpática neural con propiedades vasoconstrictoras lo que contribuye a este medio proarrítmico (9,13), confirmando su frecuencia durante el embarazo (3). Las causas más comunes comprenden la disminución temporal del flujo sanguíneo cerebral asociándose con hipotensión repentina, cambios en la frecuencia cardiaca y del volumen sanguíneo o de distribución (3).…”