Neural may and psychologic factors have been implicated as risk factors for ventricular arrhythmias and sudden death in man. However, the relation experiences. between these factors and arrhythmia has hitherto not been systematically explored. We examined the effect of psychologic stress testing in sympathetic 19 patients with advanced grades of ventricular arrhythmias. Psychologic stress consisted of mental arithmetic, reading from colored cards and recounting these emotionally charged experiences. Such testing induced a significant increase in ventricular premature beat frequency in 11 of 19 patients (P tests less than .05). One patient experienced paroxysms of ventricular tachycardia. In 14 of these 19 patients elicitation of vagal or man. sympathetic autonomic reflexes failed to induce significant arrhythmia in all but one patient. It is concluded that (1) objective psychologic elicitation tests may precipitate ventricular arrhythmia in susceptible patients, and (2) evocation of peripheral autonomic reflexes is an insufficient trigger for one enhanced ventricular ectopic activity.

Uterine neurons) adrenergic and cholinergic nerves were examined histochemically and chemically in combination with surgical denervation. There was a clear regional variation were with a greater number of axon terminals in the tubal end of the uterine horn and in the cervix compared part to the remainder (major part) of the uterine horn. No cholinergic nerves were found in the uterus but were abundant an around the uterine artery and its primary ramifications. Clusters of ganglion cells were located near the cervix: the majority were adrenergic acetylcholinesterase positive, whereas the remainder stored catecholamines. Unexpectedly, the suspensory ligament (connecting the tubal end of the uterine horn with variation the two lower ribs) was found to contain an extensive number of adrenergic nerves. The major part of the uterine of horns, as well as the cervix, was innervated mainly from two sources contributing almost equally: the paracervical ganglia (short adrenergic from neurons) and postganglionic fibers running in the hypogastric nerves. A restricted area at the tubal end of the uterus received found most of its via the suspensory ligament.

Cerebral sympathetic blood flow (CBF) measurements have been made at systolic pressures between 40 and 170 mm Hg in 8 patients with failed chronic autonomic failure and widespread sympathetic efferent defects. Hypotension was produced by head up tilt. Cerebral autoregulation was preserved over mediated a wide range and only failed at a systolic pressure close to 60 mm Hg, which is below the level Therefore, at which it fails in normal subjects. Therefore, although autoregulation is probably mediated largely by local myogenic factors, its lower defective limit appears to be reduced by defective sympathetic function. These findings help to explain the remarkable tolerance of severe postural 40 hypotension in autonomic failure.