Vasovagal fainting: deconditioning an autonomic syndrome

Risk factors for vasovagal reaction associated with cerebral angiography via femoral catheterisation

Objective To analyse the related risk factors for vasovagal reaction associated with cerebral angiography via femoral catheterisation and discuss treatment measures and prevention and control methods. Methods The data of 3107 patients on whom cerebral angiography was performed in two high-volume interventional neuroradiology centres within 8 years were retrospectively analysed. Patients were divided into the vasovagal reaction and non-vasovagal reaction groups according to whether vasovagal reaction developed. The two groups' clinical data were analysed using univariate and multivariate logistic regression analysis to examine vasovagal reaction-related factors. Results Of the 3107 patients included, 127 developed vasovagal reaction (4.09%). Of the 127 patients who developed vasovagal reaction, 123, three and one had vasovagal reaction after sheath removal, during cerebral angiography and upon femoral artery compression device removal, respectively. Differences in age, body mass index, sex ratios, proportions of patients with hypertension, diabetes and hyperlipemia, and adoption rate of femoral artery compression device were not statistically significant between the two groups ( P > 0.05). Compared with the control group, the vasovagal reaction group had a significantly longer preoperative fasting time ( P < 0.05). Multivariate logistic regression analysis revealed preoperative fasting time as the only risk factor for vasovagal reaction that was associated with cerebral angiography ( P < 0.001). Conclusion Excessive fasting time before cerebral angiography is the most important risk factor for vasovagal reaction associated with cerebral angiography.

Predisposition to vasovagal syncope in subjects with blood/injury phobia

BACKGROUND

Most subjects with blood/injury phobia experience syncope or presyncope as part of the phobic response. We tested the hypothesis that these subjects have a constitutional autonomic dysregulation that predisposes them to vasovagal syncope during head-up tilt.

METHODS AND RESULTS

We studied 11 subjects (9 females, 2 males) who had a history of syncope or presyncope only in response to a blood or injury stimulus and 11 healthy matched controls (10 females, 1 male) without a history of syncope. Blood pressure (BP) and heart rate (HR) were measured during a 15-minute baseline period with subjects in the supine position and then during 45 minutes of head-up tilt to 70 degrees. Measurements at rest did not differ between the blood phobic and control subjects. During tilt, 9 (82%) of the 11 blood phobic subjects experienced presyncope or syncope, leading to termination of the study after 22+/-17 minutes of tilt. Only 1 (9%) of the 11 control subjects experienced presyncope (chi(2)=11.7, P=0.001). Hemodynamic responses to tilt were consistent with a vasovagal mechanism in the blood phobic subjects, with simultaneous decreases in BP and HR during tilt. During tilt, systolic BP fell by 21+/-15 mm Hg (P=0.001), and HR fell by 22+/-25 bpm (P=0.01). By contrast, BP and HR were very stable in the control group.

CONCLUSIONS

Subjects with syncope related to blood/injury phobia have an underlying autonomic dysregulation predisposing them to neurally mediated syncope, even in the absence of any blood or injury stimulus. Fainting related to these stimuli may in large part be due to dysfunction in neural circulatory control, which may secondarily lead to the phobia because of repeated syncopal events.

A novel psychophysiological treatment for vasovagal syncope

The objective of this study was to evaluate the efficacy of transactional psychophysiological therapy (TPT) in a patient with recurrent vasovagal syncope (VVS) and to quantify the capacity of human dialogue to effect significant and consistent measurable therapeutic cardiovascular (CV) changes. A 31-year-old nurse with recurrent VVS and a reproducibly abnormal tilt-table test was refractory to pharmacological and conventional psychiatric treatments. She was treated with TPT. Her CV responses during psychotherapy were incorporated into the dialogue as an important source of communicative information, and she was taught psychophysiological techniques to correct exaggerated CV responses. These responses, during 16 weekly and 12 subsequent monthly sessions, were analysed using a one-way multiple analysis of variance. As TPT progressed, the magnitude and lability of CV responses as well as frequency of VVS were reduced. She has been relatively asymptomatic for 14 years posttherapy. In conclusion, (1) TPT may be an effective primary/adjunctive treatment for patients with VVS; (2) TPT may reduce syncopal episodes, perhaps by normalizing limbic input to the brainstem baroreflex system.

Blood-injury-illness phobia: a review

The empirical literature that pertains to phobias of blood, injury, or illness (BII) is surveyed. BII phobia is selectively associated with a vasovagal fainting response upon exposure to phobic stimuli, and the clinical entity may represent an exaggeration of a response that is relatively prevalent in the general population. Clinical, demographic and etiological information obtained from a series of 15 BII phobics is presented, and the suggestion is made that this disorder warrants a diagnostic category separate from simple phobia.

On the diphasic nature of vasovagal fainting associated with blood-injury-illness phobia

A detailed psychophysiologic analysis of a vasovagal faint occurring in a "blood-injury-illness" phobic demonstrated that the syncopal episode consisted of a diphasic response. This lends support to the hypothesis that vasovagal fainting in these patients is caused by an overcompensating rebound parasympathetic activation following sympathetic arousal. Treatment and research implications of this finding are discussed.