Review article: heart rate and blood pressure control in vasovagal syncope.

Vasovagal syncope is characterized by transient failure of usually reliable physiologic mechanisms responsible for maintaining both systemic arterial pressure and cerebral blood flow. Two circulatory phenomena are almost universally present: systemic arterial vasodilation and bradycardia. A third phenomenon, cerebrovascular constriction, has also been described but its contribution to the faint is less well established. The neural reflex pathways responsible for triggering the circulatory changes in the vasovagal faint are incompletely understood, but have recently been the subject of renewed interest. In part, this interest probably stems from the frequency with which vasovagal symptoms are now recognized to be the cause of fainting spells. Additionally, however, there is an increasingly recognized need to develop treatment strategies for those affected patients in whom recurrent vasovagal symptoms are particularly troublesome. It is the goal of this discussion to focus on those aspects of circulatory control, and in particular on potential interactions among certain neural and humoral systems, which may contribute to the inappropriate physiologic responses associated with the vasovagal faint.

The psychoimmunological association of panic disorder and allergic reaction.

During treatment of out-patients suffering from DSM-III R panic disorder (PD) with and without agoraphobia, our attention was drawn to a high frequency of comorbid allergic reactions. In a controlled study, the prevalence of immediate type I reactions was determined in panic patients. Conversely, the prevalence of psychological disorders was recorded among allergic patients. Altogether, 79 out-patients with PD, 100 type I allergic out-patients and 66 controls underwent structured clinical interviews and tests for allergies. Of the patients suffering from PD, 70 per cent displayed type I immediate reactions (controls = 29 per cent). Vasodilatation (often approaching circulation collapse) is a frequently occurring allergic syndrome which is a very dramatic experience. Fifty per cent of the allergic patients showed mild to severe psychological disturbances (controls = 25 per cent); and 16 per cent had problems requiring treatment (controls = 9 per cent). Ten per cent of the allergic patients revealed PD (controls = 2 per cent). The association between PD and allergic (vasomotor) reactions was found to be highly significant. A functional relationship is hypothesized in terms of conditioning cognitive and vasomotor interactions during autonomic arousal.