Responsiveness to the emotion and autonomic measures in syncopal profile: a preliminary study

“E caddi come corpo morto cade” (And fell, even as a dead body falls). So in the fifth canto of Dante Alighieri’s Divine Comedy , in what is probably the first literary description of an emotional syncope in the world literature. The neurally mediated syncope(NMS) known as neurocardiogenic syncope, or vasovagal syncope (VVS), or simply “fainting” is by far the most common cause, with 60% of the total prevalence of cases of syncope found. It is a common clinical problem in all age groups and affects 40% of people during their lifetime. Major lines of evidence suggest that NMS is not a disease, but a “characteristic” of the individual. Given that this reflex is sporadically displayed, the most likely hypothesis is a “heart protection mechanism” during particularly stressful and dangerous conditions. In fact, the slowing of heart rate induced by the vasovagal reflex may constitute a beneficial pause of cardiac pump. The purpose of this study is to explore the hypothesis of a psychogenic etiopathogenesis at the base of the NMS. Therefore, according to several studies’ suggestions, we investigated the autonomic response to emotional stimuli with negative valence and high arousal that could be related to the mechanisms of anxiety, phobia and depression. For this reason, we examined a preliminary sample of healthy subjects to verify there is a significant increase in autonomic activity when people watch to these stimuli. Seven subjects took part to the experiment. The partecipants were requested to look to some images (IAPS pictures). The task was composed by four blocks of images interspersed by a brief pause; images were displayed on a computer screen. Images were divided into five categories, obtained by crossing of two emotion’s dimensions: valence and arousal. The five categories, thus, were: positive valence and low arousal; positive valence and high arousal; negative valence and low arousal; negative valence and high arousal; neutral images. For the duration of the task, physiological measures were recorded through a biofeedback. At the end of the task subjects were asked to answer to some psychometric tests: Big Five Questionnaire (BFQ-2) for personality, STAI-Y for anxiety traits, Beck’s Depression Inventory (BDI-2) for depression traits and BIS BAS (Behavioral Approach System - Behavioral Avoidance/Inhibition System) for the role of behavioral inhibition and activation systems in relations to stimulus-situations. The results showed an increase in skin conductance (SCR) and pulse (PULS) values for the negative valence and high arousal stimulus category, also supported by psychometric indexes. The fact that this trend is impaired in subjects with a history of recurrent NMS has to be tested in a second phase. Indeed we supposed that this increasing of the autonomic measures is higher in NMS and it is followed by a sharp decline of these parameters, in agreement with the dominant theory on the NMS.